Re: Topband: Carrier on 1814.0 kHz

[Lee STRAHAN]

Hello John and top banders.
   I have been hearing what appears to be the same on/off carrier
transmission. I also hear one up near 1830 at the same time. The same slow
CW tones.  I believe these transmissions to be a form of QRSS or Very slow
CW. We had an offending signal we thought was a stuck transmitter here in
the NW about a year ago. We tracked it very close in Seattle before somebody
surfaced that knew the guy was running QRSS. The signal went on for days
just like the ones at the present. It finally went away with no ID
discernable.  I find it a bit hard to believe they are identifying their
stations every 10 min as the rules call for. I will look at direction
tonight if the signals are still on. 

Lee  K7TJR  OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of John
Kaufmann
Sent: Sunday, January 10, 2016 8:40 AM
To: topband@contesting.com
Subject: Topband: Carrier on 1814.0 kHz

For weeks I have been hearing a fairly strong persistent signal on 1814.0
kHz.  It is either a continuous carrier or a series of slow CW dashes.  The
signals I hear periodically from buoy beacons come and go.  This one is
persistent.   I hear it only in darkness and not in daylight, so I presume
it is beyond groundwave range.  From my location near Boston, the signal
peaks at a heading of approximately 230-240 degrees.

 Anyone else hear this?  If so, from what direction?

 
73, John W1FV

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Re: Topband: 4SQ vs. 8 circle rcv

[Lee STRAHAN]

Hi Guys, I have just updated my antenna comparison chart with some
enlightening plots that show antenna comparison in 3D. 
Interestingly enough my experience is as you get to the higher RDF antennas
each dB seems to be very important.
  Frank is quite right , One can never have enough receiving antennas.
Plots at   http://www.hizantennas.com/receiving_antennacomparison_char.htm

Lee  K7TJR  OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
donov...@starpower.net
Sent: Wednesday, January 13, 2016 10:47 AM
To: topband 
Cc: Bill Hider ; Mike Waters 
Subject: Re: Topband: 4SQ vs. 8 circle rcv

Hi Mike, 


Beverages, four squares and 8-circle arrays are all excellent receiving
antennas. Based on much on the air experience, my W8JI passive 8-circle BSEF
arrays have much narrower beam width than my
580 foot Beverages and especially compared to the broad beam width my full
size transmitting 4-square. M y 8-circle arrays also have very low side lobe
levels. The 8-circle has a high RDF value because of its narrow beam width
and low side lobe levels. 


Every year we make many QSOs using the 8-circle array that could not have
been made with any of my other receiving antennas; however probably 99% of
my QSOs could have been easily made with either a Beverage or the 4-square.
It just depends on how important that one percent is to you. 


You can never have too many antennas... 


73
Frank
W3LPL 












- Original Message -

From: "Mike Waters" 
To: "Bill Hider" 
Cc: "topband" 
Sent: Wednesday, January 13, 2016 2:56:07 PM
Subject: Re: Topband: 4SQ vs. 8 circle rcv 

According to what I read there, there is little difference between the two. 
That seems odd. Was some information left out, or did I read the wrong .pptx
file? 

73, Mike
www.w0btu.com 

On Wed, Jan 13, 2016 at 1:23 AM, Bill Hider  wrote: 

> This presentation is titled: "Receiving Antennas" ... : 
> 
> http://www.contestuniversity.com/main/page_files.html
> 
> This presentation answers all of your stated questions and more. 
> 
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Topband: Summer in the Northern Hemisphere - LIghtning Maps

[Lee STRAHAN]

Wonder why the TOGA map shows all that below the equator activity and 2 that 
show the equator of the others do not.
Seems strange to me.

Lee  K7TJR
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Topband: XZ4ZW

[Lee STRAHAN]

I was super pleased to work Ken K4ZW on 160 this morning while he is in XZ as 
XZ4ZW.
  Ken had been trying to work North America for three days when the band 
finally opened a bit
and several West coast stations are in the log.  Best signals seem to be 1 hour 
before sunrise here.
Look for him around 1817.5  . I believe he is there for at least one more day.
  Thanks Ken for hanging in there and all your hard work.
  Lee  K7TJR   OR
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Topband: XW4ZW

[Lee STRAHAN]

   My friend Rich K7ZV just corrected me on Kens call. I been up at 3 a.m. for 
3 days.
His call is XW4ZW   not XZ4.  Sorry guys for the typo. Back to sleep.
Lee  K7TJR  OR


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Re: Topband: VP8STI from Oregon

[Lee STRAHAN]

Tree and all the folks,
   It was 0430Z when I knew for sure I was hearing the VP8 station. The
first thing recognizable earlier from the SE direction was the 5NN timed
about 1 QSO apart. At about 0445 Z the signal was about 70 % copyable
between the frequency cops QRM. I heard the callsign and the operator
repeating signal reports to some. It was possibly good enough for a Q but I
kept looking for another couple of dB or so which I felt would make it 100%.
By 0500Z they were fading and not to be heard again except for an occasional
burst of a character or two. So, I will be in the fray listening again.
   I constantly checked all directions and the signal only came from the SE
here.
   Good luck all and congrats to all who made it so far. What a hobby!
 Lee   K7TJR   Culver, OR

>Not much was heard at my QTH in Hillsboro.  K7TJR reported hearing them as
well as W7VS - both about 100 miles Southeast of me.  Not sure either one of
them heard them well enough to make a QSO.  W7EW reported hearing possibly a
short burst.

W4ZV reported on the topband chat page that the signal seemed to be coming
in from the North!  For those not familiar with the ON4KST chat page - this
Is a useful tool for collecting data on where the DX is being heard in real
time.  Check out www.on4kst.com.

At any rate - it seemed that they were hearing well and quite a number of NA
stations made it into the log.  Congrats to those who made it - and good
luck to those still in the hunt.

Tree N6TR
Hillsboro, OR (via remote from XE1)

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Topband: VP8STI last night in Oregon

[Lee STRAHAN]

   Tree, the conditions to VP8 were much worse last night to my location.
I did not hear them at all last night where I had heard them briefly the night 
before.
In addition, the storm noise to the SE was quite noticeable.
Dan W5XZ in TX confirmed that he had bad storm static in the area.
I checked all directions and even horizontal with a low dipole. NADA.

Lee  K7TJROR
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Re: Topband: VP8STI Humor, Design engineer trauma

[Lee STRAHAN]

Rich uses the Hi-Z 4-8 Pro

Lee

From: Mike Waters [mailto:mikew...@gmail.com]
Sent: Saturday, January 23, 2016 11:06 AM
To: Lee STRAHAN <k7...@msn.com>
Cc: 160 <topband@contesting.com>
Subject: Re: Topband: VP8STI Humor, Design engineer trauma

Exactly what antenna was he using? All we know is that it wasn't the Hi-Z 8A.
73, Mike
www.w0btu.com<http://www.w0btu.com>

On Sat, Jan 23, 2016 at 12:56 PM, Lee STRAHAN 
<k7...@msn.com<mailto:k7...@msn.com>> wrote:
 he was using one of my own antennas invented ... I am doubly crushed that it 
was one of my second tier designs that had whipped me so soundly.

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Topband: VP8STI Humor, Design engineer trauma

[Lee STRAHAN]

   Well, it was not as if I did not know it was going to happen someday, I had 
remained pretty cheeky until this time. I had often knew it was sure to come. I 
have remained pretty self-content that I had invented the ultimate DX antenna 
for the state of Oregon. The Hi-Z 8A. In the hours that I had spent trying to 
work DX on 160 I had remained convinced that I could hear everything that 
anyone else in Oregon could hear. After all I had taken 5 years out of my early 
retirement life inventing surely in my mind the monster of all receiving 
antennas for 160. But it was last night the 22nd of January 2016 when I was 
finally humbled by my friend in Grants Pass Oregon some 225 highway miles 
Southwest of me.  I knew it was coming someday. I had my earphones plugged into 
to my trusty Orion 1 transceiver when I saw a post from my friend that he was 
hearing the VP8 very well and of all the nerve he was using one of my own 
antennas invented right here in this little town of 1360 people wi
 th no stop lights. Of all the nerve. Well I said to myself the VP8 will clear 
up here any moment. I listened and tuned the Old Orion, which by the way I 
still think is better at 160 than the K3, sure enough I could hear a character 
or 2 of the VP8. I listened and listened and it never got but little better. I 
called a few times when I was convinced I might just squeak through but alas I 
thought he may have come back to me but horrors, maybe I remain in the group 
reported to have been called and not heard. And so it is here on the morning of 
the 23rd I remain crushed by my own ego and at my own hand. Congratulations 
Rich K7ZV, I covet your mountain top location now because you have answered the 
question I have pondered for a long time. Now I am truly convinced that the 
mountain top locations really must be better on the low frequencies like 160. I 
am doubly crushed that it was one of my second tier designs that had whipped me 
so soundly. And so it is with my mind turning at t
 op speed today, which one of my antennas or how many should I place at this 
1250 foot peak just 2 miles due South of my QTH with NO power lines and would 
it be worth the effort. Hmmm of course it would after all I have what I read a 
long time ago on Tree's web stuff. I am inflicted, yes you guessed it the 
dreaded 160 disease. Hmmm wonder if I could hear 630 meters up there. So it is 
now I thank my friend Rich which took the smile off my face last eve and left 
me with Hmmm why not, that peak sure is appealing and it belongs to the Federal 
grass lands.  Surely I could get a grazing permit for some signal hungry 
aluminum  and inconvenienced electrons corralled in some suitable enclosures. I 
need to call my friend whom is a digital guy and pick his brain about wifi 
remoting. I gotta go guys, got lots to do to prepare for next year. Granted my 
health, I am in.

Congratulations to all whom have made it. I will try until they leave. It was 
better last night, surely it will be better tonight.

Lee  K7TJR   Central Oregon


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Re: Topband: VP8STI Humor, Design engineer trauma

[Lee STRAHAN]

Hello again Mike, Thanks for the question,
I have had as many as 4 of the directional Hi-Z and a new undisclosed 
design experimental Low impedance element arrays running at one time for 
comparisons. Some over 1000 feet apart.
  From the plots of Eznec there is scant 1.4 dB RDF difference between the 4-8 
Pro and the superior all active 8A. Also what I have observed and have nothing 
but anecdotal evidence for is that the all active 8A seems to outplay to the 
ears what Eznec or 4NEC2 predicts using RDF alone. These NEC comparisons are at 
a 20 degree angle of incoming signal elevation. If you look at the 3D plot 
comparisons at http://www.hizantennas.com/receiving_antennacomparison_char.htm  
you will see that the side lobes put there purposely to get the RDF up in the 
8A are very very low in elevation.  I have always conjectured that this was the 
reason that the 8A would outplay the 4-8Pro Eznec comparisons  in my fields. 
Assuming that local noise and noise in general is higher  angles these low 
elevation side lobes would not pick up the high angle noise. This could be 
responsible for an observed increase over RDF performance. There are a lot of 
variables involved so it remains conjecture at this time.
  The slightly narrower forward beam of the 8A may also be responsible. When 
you start using antennas with this kind of pattern squeezing to make high RDF 
it is absolutely imperative to be at least 1000 or more feet away from power 
lines and TX antennas as it takes so little coupling to change the pattern and 
resultant RDF. This makes comparisons very difficult.
For instance, it is theoretically possible to take the same 8 element 200 
foot diameter circle and get over 15 dB of RDF with a 31 degree beamwidth, a 
horrible looking pattern, and 22 dB front to back. The absolute maximum 
directivity according to MT Ma and his book.  It takes enormous precision in 
everything involved with this design including likely impossible electronics, 
cabling, ground incontinuities and environmental differences. Not to mention 
the narrow beamwidth making the need for 16 elements in this footprint to cover 
the entire azimuth. I do not believe that you could make this antenna work 
without a mile or better separation from other objects of any kind.

Short answer, 8A is 1.4 dB RDF better by Eznec.

Bear in mind the fact that one can never have enough receiving antennas at any 
given time. The ionosphere is a fickle beast at best.

Lee  K7TJR  Central Oregon


Thanks. Assuming for a minute that it wasn't the location, how might that 
antenna have been superior?
73, Mike
www.w0btu.com

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Re: Topband: A 160m Noise problem

[Lee STRAHAN]

  Greeting top-banders and Ed,
   You could simply disconnect the elements from your Hi-Z amps at each
element. This will tell you if the noise is being generated in the system or
coming in the air.
My guess from experience something some distance from you is following your
power wires. 
Good luck
Lee   K7TJR

Hello Topbanders

I would like to explain my noise issue to get opinions on search and Destroy

This noise is covering the 160m band only, 80m is good ! I'm using a HI-Z
receive 4 SQ and the NW direction is as quiet can be . All other directions
are noisy with the NE being the worst , SE almost as bad and 
SW is somewhat OK.   The noise starts at 1780 Khz and rises quickly to 
its peak at 1820 Khz ! from there the noise levels off to 1880 Khz and
slowly drops to nothing at 2070 Khz ! Wish I could post a screen shot of my
panadapter for y'all to see, I'll be happy to send JPG file off list !
I was thinking maybe water in the RG6 and with the Bias T the Hi-Z uses,
this may be my problem but disconnecting and testing all the coax  using the
20meg scale ... all checks good ! I may replace the RG6 anyway but thinking
of running a beverage at 165 degrees and see if the noise is still there .
Was going to run the beverage anyway in hope of hearing Heard Is .
At first I was thinking power line noise , I checked for noise using a
144Mhz AM receiver and 3 el yagi . I did find some noise to my NE but gone
today after the big rain . 160m noise is still with me!

Now I have parts ordered to build a small 160 loop . With that and my K3
I'll move to different locations and see how that works out .

Yes I have unplugged everything in the house and no switching supply's that
we leave plugged in . With computers off and using VFO I can see the S meter
rise and lower sweeping through the 160 band .

I've ask 2 of my neighbors to disconnect their elec fence with no joy .

I have to give my pasture a couple of days to dry out , then I'll run the
beverage and replace the RG6 on the RX 4 SQ with new flooded coax .

Oh and I also tried a BCB filter ..

Any Ideas what could cause the 160 only noise ?

Thanks Ed N5DG


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Topband: VOA antenna farm

[Lee STRAHAN]

These two sites are also gone now. Hauled away for scrap. Acres of stainless 
mesh wire ground plane as well.
http://www.k7tjr.com/fps118_oth_radar.htm

Lee  K7TJR
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Re: Topband: RDF in the real-world

[Lee STRAHAN]

Hello JC and others,
   I must take a little issue on being able to measure the vertical arrays. 
While it may be true that it is hard to measure, you can indeed see the pattern 
quite well by looking at different stations and switching around the compass. 
It does not take long before you can observe the pattern and can tell that 
there may be something wrong with it. In my case there are 2 lobes on the side 
of the patterns of my best antennas and you can certainly see the results for 
even slightly skewed signals because of them.
   I recall an instance a few years ago where W0FLS was able to DF a long 
standing carrier on 160 within 1 or 2 degrees using his 8 circle and his 
observations about pattern.
  So it is like your RDF and signal to noise description, it is not easily 
measurable but observable. Yes, Directivity rules.
Sorry I missed your webinar due to other commitments. I will be able to view it 
when it is archived.
Lee  K7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC
Sent: Friday, March 04, 2016 9:31 AM
To: k...@myfairpoint.net; 'Carl Luetzelschwab' ; 
topband@contesting.com
Subject: Re: Topband: RDF in the real-world

Hi Carl

Yes, the concept is assuming equal density noise spread uniform. However there 
air point everybody wants to hide. Vertical polarized antennas based on phasing 
elements does change directivity and does have interaction with others vertical 
elements. It is hard to measure it because you cannot turn the antenna for 
different directions to measure it.

The Bog is a travel wave antenna, and it is based on the difference in velocity 
on the ground and on the wire, it does not interact or deteriorate with other 
vertical structures like the flags. The SAL antenna is really a K9AY very 
complicated but same directivity and RDF, the TX antenna does deteriorate the 
pattern and you can’t see the same reduction in signal to noise ratio because 
the REAL RDF is no longer the same as the CALCULATED RDF. The BoG  performance 
is more predictable, like the beverages and the real RDF is close to calculated 
RDF.

Like you see in the diagram when I remove the detuning skirt from my TX 
antenna, with that tiny yellow jumper grounding the skirt, the radiation patter 
of my excellent VWF become useless without detuning the TX antenna.

The Webnair is limited to one hours and there are interesting aspects of each 
antenna that deserved more time to elaborate, maybe next time with dedicate one 
hour for each type of antenna.

The  idea was to quantity what directivity can do for you in practical DXing.

Regards
JC

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K1FZ-Bruce
Sent: Friday, March 04, 2016 10:02 AM
To: Carl Luetzelschwab ; topband@contesting.com
Subject: Topband: RDF in the real-world


I agree. There are times, especially in disturbed condx, when my BOG antennas 
are "head and shoulders" better than my other antennas. 
 
73
Bruce-K1FZ
www.qsl.net/k1fz/bogantennanotes.html
 
 
 

   I can't vouch for JC's numbers (his numbers may be QTH specific), but 
the concept is believable since the theoretical assumption of isotropic noise 
falls apart in the real-world. My BOG *at times* gives much more of an SNR 
improvement than the SAL-20 (using measurements on a calibrated S-meter) in 
spite of the small difference in RDF between the BOG and SAL-20. 

Carl K9LA
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Topband: Waller Flag construction and performance

[Lee STRAHAN]

  Ken, did you remember the 180 degree phase inversion needed on the Waller 
flag.
It will act like a very large signal level single loop if not.

Lee K7TJR

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Re: Topband: LDEs, witches and magicians

[Lee STRAHAN]

Greetings All,
I am afraid I have to take issue with you Wolf. And this may be a clue. I 
also have experienced echoes on 160 meters. Maybe it depends on longitude or 
latitude or something like that. N6TR not being too far away has also 
experienced them.  All that being said I am positive due to my observations 
that a short delay has occurred here twice. During the one event one station 
sent me a message asking what was wrong with my signal. Tests confirmed there 
was nothing wrong with the signal and the echoes slowly faded away. 
Unfortunately I did not have the presence of mind to determine directionality 
or make a recording. The echoes were quite strong and lasted for several 
minutes. Guessing would put them at less than 100 mSec separation. My first 
thought at the time was that my receiving array was failing in some strange 
mode but that was definitely not the case.
   Lee  K7TJR  OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Dr. Wolf 
Ostwald
Sent: Tuesday, February 07, 2017 10:15 PM
To: topband@contesting.com
Subject: Topband: LDEs, witches and magicians

hello reflectees,
i never ever experienced echoes on 160. And i do a lot of transmitting and have 
relatively sensitive rx systems.
Given the laws of field expansion and attenuation i consider it a hoax.
I have had round the globe echoes on 20m. But was using 6 el monobander with 
power and at the rite time, when we had greyline. Sometimes 2 to three rounds. 
That was physically explainable.
Anything else is from the land of Alice.


73 de wolf  df2py
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Topband: 8 element antenna - Amplifier placement

[Lee STRAHAN]

 Hello Gary,
   Spray painting the elements is no problem. As far as mounting the amps to 
the elements I would not recommend that. It likely could compromise 
performance. It would be much better if you could take a steel post like a 
piece of rebar and provide a second place for the amps to mount  with just the 
wires reaching the element and ground. If you have to lengthen the leads to the 
amp do not lengthen the ground lead any more than absolutely necessary. 
Lengthening the element wires will have to be done exactly the same length and 
dressed as closely the same way as possible on each element/amp.
  Lee  K7TJR


Subject: Topband: 8 element antenna - Amplifier placement

I'm so close to being done with putting this together. I have all 8 antennas 
made @ 23' each the tip section is .5" and the base is .850" I'm using a 3/4" 
fiberglass rod as an insulator 

doctorgary.net/Hi-Z-8-Pro-1.jpg
doctorgary.net/Hi-Z-8-Pro-2.jpg

I am having a conundrum with the placement of the enclosure for the preamp 
mounted at each antenna and need some advice. The problem is I am at sea level 
and the antennas will be mounted in a location that will possibly get a storm 
surge during a Hurricane, it ruined my remote coax switch during Sandy from 
this very reason. The preamp does have a silicone gasket but if the amp gets 
submerged in salt water, I'm sure it will get past the terminals and ruin the 
amp. I have no alternate choice, this is the location where I have to put the 
array.

Seeing the photo of the end cap on the PVC tubing with the zip tie holding the 
amp in place (to protect from rain & Snow), gave me an idea for the solution; 
At the top of the PVC tube, make two opposing holes, run a loose loop of thin 
wire through and twist together. Run the coax up & over the wire to hold the 
amp elevated inside the tube, all the way to the top. Use a rubber cap with 
radiator clamp to secure the top and make it truly airtight. Now if the tide 
water from a storm surge encroaches, there will be a pocket of air inside and 
will be unable to push high enough to reach the amplifier. I tried this with a 
Mason jar and the water did not get very high in the upside down jar.

doctorgary.net/Hi-Z-8-Pro-3.jpg 

So here's the dilemma: As a further hedge against water damage assuming there 
are strong winds making waves (they would not be breakers, just waves in the 
marsh) at this time, I'd like to raise the placement of the amplifier so it 
would be another foot higher than standard placement which is on the base below 
the insulator. This would require me to clamp the PVC on the antenna instead of 
the base. Can anyone see how this might be a problem with operation?

Also, I'd like to spray camo paint on the elements so they don't stand out. 
When the leaves come down, I'd prefer the neighbors not see the elements, 
they're nosy enough as it is. I think I remember reading a layer of paint on 
the element shouldn't cause a problem, is this correct?

Thanks & 73,

Gary
KA1J



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Topband: active antenna height

[Lee STRAHAN]

Thanks John, I have been faced with this capacitive loss thing for a long
time. It became quite necessary to reduce it to make my all active HI-Z 8A
array work well. Especially with the early Hi-Z amps with 6dB loss.
Here is a list of elements of different lengths and their subsequent output
source capacitances and system losses. This list is for an element diameter
of 0.625 inches. And a total capacitive load of 15pf. 
10 feet  =34.6pf.. .70.. -3.01dB
11 feet  =37.3pf.. .71.. -2.97dB
12 feet = 40.1pf.. .73.. -2.73dB
18 feet = 56.4pf.. .79.. -2.05dB
24 feet = 72.6pf.. .83.. -1.61dB

 There is about 0.1 dB per foot increased output signal as a result of the
capacitive division and increased length. Pretty much insignificant with the
state of the art.
 It becomes quite significant with highly capacitive input amplifiers, their
connecting wires, or element insulators constructed with excess capacitance
between the element and ground.
Going from 18 to 24 foot elements using both John and my numbers is about a
3.4dB increase in signal.
Here is a couple fun tools I have used over the years that apply.
"http://www.daycounter.com/Calculators/Whip-Antenna-Design-Calculator.phtml;
"
http://www.learningaboutelectronics.com/Articles/Capacitor-voltage-divider-c
alculator.php#answer"

Lee  K7TJR


Lee,

The NEC-4 analysis is based strictly on gain and does not take into account
the loading of any amplifier input capacitance, which can modify the scaling
of signal level obtained at the output of the amplifier with increasing
vertical height.  A very short vertical, in the range of 10 to 25 feet,
exhibits a feedpoint impedance that is almost entirely capacitive reactance.
NEC-4 shows that the capacitance is a few ten's of pF, with the capacitance
increasing with increasing length.  On my own 15 foot verticals, which uses
4 foot ground rods, I measured the vertical's capacitance as about 50 pF on
160m using an accurate impedance analyzer.

This means that the voltage at the output of any feedpoint amplifier will
depend on the voltage divider relationship that occurs between the
capacitance of the vertical and the input capacitance of the amplifier.
This reduces the maximum voltage output that is available from the vertical
at the amplifier's output.  The maximum output is obtained (theoretically)
when the input impedance of the amplifier presents a conjugate match to the
antenna impedance, which, in this case, would be inductive (a very large
inductance, in fact).  But this is the same as saying the vertical is now
resonated to the frequency of interest by the amplifier's input inductance.


As a practical matter, the amplifier gain can easily make up any
inefficiency in coupling signal out of a short vertical, subject to the
considerations of noise added by the amplifier, as I discussed in my earlier
post.

73, John W1FV




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Topband: active antenna height

[Lee STRAHAN]

John, do your NEC4 numbers take in to account the signal that actually
arrives at the element insulators and the amplifiers with their inherent
input capacitances as a load on the element source capacitances. Or are you
using NEC gain numbers to get the 0.5 dB per foot?

Lee  K7TJR

>>>A while back, while designing my own "active" receiving array of short
verticals,  I did a NEC-4 analysis of how the behavior of a very short
nonresonant vertical varied with height. The vertical I modeled used a
4-foot ground rod inserted in the ground, which is typical of "active"
vertical systems.  NEC-4 is necessary to model anything buried in the
ground.  NEC-2 won't do it.

The gain of a very short vertical with just a ground rod is obviously very
low, hence the need for amplification.  The principle effect of increasing
height is to increase signal output.  The NEC-4 analysis showed a scaling of
roughly 0.5 dB of increased signal output on 160m for each 1 foot increase
in length over the range of 10 to 25 feet.  Keep in mind that this is
strictly a modeled result with the usual caveats, and I don't have any
measured data to confirm it.  However, I do believe the trend shown by NEC-4
is correct, if not the exact numbers.

On 160m, you want to be sure that the system noise floor is set by ambient
atmospheric noise and not the internal noise of the amplifier that provides
receiving gain.  This is where the signal level delivered by the vertical
matters, because the signal includes the atmospheric noise (as well as local
man-made noise) picked up by the vertical.  You want the external noise to
overwhelm the internal noise of the amplifier.  The point at which this
happens depends on how noisy your location is.  Ironically the quieter your
environment, the more "signal" you need from the vertical to be sure this
happens for a given amount of amplifier noise, and therefore the longer the
vertical required.

Once you reach the point where the atmospheric noise dominates the amplifier
noise, there is really no receiving benefit to a longer vertical in
performance terms.

73, John W1FV



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Topband: active antenna height

[Lee STRAHAN]

Hello Gary and all,  The answer to your question depends on how quiet your
location is. If you have an extremely quiet location I would go with another
section of tubing for 23 feet overall with the Hi-Z. If your location is
pretty normal for noise then 18  feet or so will be fine with the Hi-Z
array. There are times here in the early morning when the band noise drops
below my array noise for a short period of time and I have been using 20
foot elements. 
  Another point to consider is 3/4 inch fiberglass rod is easy to get and
has proven strong enough for element insulators.  Adding a few feet of 3/4
tubing to each element would make your insulators much easier to construct
and increase array gain. You can always add more length later as you see the
need.
Four inches of overlap has seemed to work well.
   Lee   K7TJR


>I've decided to make the plunge and buy one of the 8 element active arrays
for 160M-40M. Looking at the price for the antenna kit, it's just too much
considering the cost of the electronics, so I need to roll my own.

I was thinking of getting the Telescoping Aluminum Tubing that comes in 6'
lengths from Texas Towers; .375", 5" & 6.25". If I slide each inside 6",
that'll come to a 17' tall element. Is that sufficient height? Would adding
another 2-3 feet make any difference with these kind of active antennas?

73,

Gary
KA1J
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Topband: 75 ohm RG6 to 50 Ohm radio

[Lee STRAHAN]

Actually there is a reason or two to match the feedline impedances when 
using these active antennas.
There are amplifiers in most of these systems that rely on their matched 
impedances to produce their best IMD capability. It may not matter in some 
areas of the world but in others with high levels of broadcast signals it 
definitely could. This of course is also dependent on the length of 
transmission line which can make the mismatch worse or even better under 
certain circumstances. Then if the mismatch is made better on one band due to 
mismatch it likely won't be on another band. One other reason that matching 
matters is the impedance a mismatched line loads the combining circuitry can 
under some circumstances cause phase and amplitude errors. This can change the 
originally intended pattern of an array. In the case of the Hi-Z arrays they 
all are supplied with an amplifier that has a 75 ohm input impedance so the 
array controllers stay accurate in terms of phase and amplitude. However this 
amplifier like most post amplifiers partially reflects its output load changes 
back to
  its input changing the input impedance. Thus the reason for the 75 to 50 ohm 
transformer as it keeps the amplifier happy.
  Now this may or may not affect some users but as a manufacturer of these 
arrays it is important to insure that these arrays will work well and do it at 
every install around the world. We have seen feedlines as short as 3 feet up to 
the 1000 foot runs I use and one that I heard of at 2000 feet.
So my point is why would one want to possibly give away some performance 
when it could very easily be done correctly.
  One caveat is that the Hi-Z 4 and 4-8Pro have an internal buffer amplifier 
designed specially to eliminate the amplitude and phasing problems arising from 
load mismatch but it cannot maintain its IMD capability under some incorrect 
load conditions. Other models do not include this internal buffering of the 
output signal.
Lee   K7TJR  OR


>I suppose I need to ask if worrying about impedance at this point in the
> system is really worth the trouble.
>
> Once signals have gone through one or two stages of amplification - would
> a
> loss of a db or so in signal strength really matter?
>

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Re: Topband: 75 ohm RG6 to 50 Ohm radio

[Lee STRAHAN]

 Yes Ed, You have the right numbers. It won't matter which windings are first 
or last. You can even wind 4 then wind 1 more and use it as an autotransformer 
where the 1 turn is added to the 4 for 5. Any of these will work fine at these 
TOP Band and higher frequencies. This ratio is not perfect but will work just 
fine. It would be 50 to 78 ohms which in our world is close enough.
 Let us know how your new 8 circle works. Maybe even compare it to your Hi-Z 
4-square.
Lee   K7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Ed Stallman
Sent: Tuesday, September 27, 2016 8:35 PM
To: topband@contesting.com
Subject: Topband: 75 ohm RG6 to 50 Ohm radio

My receive antenna is 75 Ohm RG6 connected to my radio and I want to wind a 
2873000202 binocular core to step 75 to 50 Ohm's . I seen this info on W8JI web 
page but can't seem to find it again.

I do remember it's 4 turns 50 Ohm and 5 turns 75 Ohm and all wires come out the 
same side of the core . Am I correct so far?

Does it make a difference which winding I wind first ?

Thanks in advance , Ed N5DG



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Re: Topband: Modeling Transmit Antenna Affect on Rx Antenna Performance?

[Lee STRAHAN]

Paul, I suggest you talk to Gary KD9SV as he built a Hi-Z around his TX 
antenna. 
  Incidentally the ground radials under the Hi-Z is not a good idea. I suspect 
you would have to use NEC4 to see the real effect of the radials. I have not 
made a test myself to see how close radials could be. Disconnecting the T 
element on one band like 160 will work for that band but likely will not work 
the same on 80 meters. Leaving it connected might be better. Same situation 
with the feedline impedance looking back toward the radio. That may change with 
band as well.
Lee  K7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Ferguson
Sent: Friday, September 30, 2016 12:10 PM
To: topband@contesting.com
Subject: Topband: Modeling Transmit Antenna Affect on Rx Antenna Performance?

For transmit I use a 160M T antenna with on ground radials. I am considering 
installing a Circle-8 receiving array such as one made by Hi-Z. The receive 
array would be very close to the T, maybe within 100 feet. I am using EZNEC to 
see how the transmit antenna proximity affects the pattern of the Rx array.

I have a simple EZNEC model of a 4 square Rx array. The model uses a source on 
each 20-foot Rx vertical, with the pattern determined by the phase of each 
source. 

I put models of the T and the Rx array in the same EZNEC model. With the source 
removed from the T, the radials are connected to the T portion of the antenna. 
This configuration shows a big degradation in Rx front to back ratio. If I open 
the T at the feed-point by either putting in a source with zero current or 
simply breaking the connection between the T and its radials, running the model 
shows little to no affect on the Rx pattern.

I could use a relay at the antenna to disconnect the feed line near the 
feed-point when not transmitting, but I would rather avoid the relay because of 
running QSK and wanting to avoid the wiring run.

My modeling runs, using either an effectively open or shorted feed line at the 
T, do not represent my real system because it is not open or shorted. The feed 
is about 350 feet of coax to a K9YC-designed common-mode choke and a 1:1.56 
unun. I am wondering if there might be value in disconnecting the feed line 
from the antenna and measuring the impedance looking back into the 
unun/choke/coax string. Take this impedance and add it as an RLC network 
connected across the feed-point of the T antenna. My thought is this would be 
close to what the Rx array is really seeing when I look for the affect of the 
nearby T in the EZNEC run.

Am I on a decent path or lost in the woods?

73,
Paul, K5ESW


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Topband: Strange resistance between Beverage ground rods

[Lee STRAHAN]

Hello Herb and fellow Top Banders,
   When I had Beverage antennas here I was never able to read the ground 
resistance here as well. The reason it did not work here is there was actually 
a small DC voltage difference between grounds apparently developed by galvanic 
means or currents in the earth. This voltage does not allow a DC resistance 
meter to read correctly.
   As a side note there is a 1,000,000 volt DC power generation line running 
from Celilo Oregon to Sylmar California that uses the Earth as one conductor. 
Its no wonder here there is DC across portions of the ground. Just look up 
Celilo converter station if you are curious. 3200 megawatts transported from 
Oregon to California through the ground! This line is within 20 miles of my 
farm. This may or may not be partly responsible for the DC difference on mine 
or others Beverage antennas.
Lee  K7TJR   OR


I have reflection transformers at the end of every two wire Beverages which I 
try to test by measuring the wires on the feed end. I remove the transformer 
from the two wire WD1-A and check the resistance between the two wires which 
tells me that through the reflection transformer I have continuity. It measures 
about 40 ohms wire to wire, this is done when I notice any performance change 
of the antenna. Now come the next test that baffles me completely.  When I 
measure from either wire to my ground rods alone, to see what the return 
resistance is, I get reading 
in the vicinity of 20K  across the 900 foot run.I understand that if 
the reading was very low it would defeat the whole Beverage principle.  
But is 20K Ohms reasonable, very good, or marginal?  I use three foot foot rods 
at either end and when I pull one out yesterday before moving it the bottom 1/4 
was moist and muddy. That Southern end of several reversible Beverages  is 
located about 100 feet or less from a salt marsh or salt pond.  I also have to 
such antennas made up of ladder line a DX Engineering components.  They all 
appear to be working well even though large grass has reach and covered portion 
of some of them.

But my question is what is a reasonable or good return ground resistance for a 
600' or 900' Beverage.  I haven't found any sources of information expect the 
saying that the higher Resistance the better. Is this correct?

Herb Schoenbohm, KV4FZ

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Re: Topband: Epsom salts & Rx Antennas

[Lee STRAHAN]

Hello Gary and Top-Banders,
  Gary, I would be more inclined to think in your case you would be better off 
with some radials laid out on each vertical the same way. Short verticals no 
longer than the element height should help more than trying to influence the 
ground conditions. Each vertical must have the radials laid out very closely to 
the same way. Maybe 8 to 10 radials should make a decent ground for the high 
impedance elements.
Lee K7TJR  OR


The earlier discussion about Epsom Salts and Beverage grounds got me to 
thinking about my active antennas and if it might be helpful for my situation.

I have 8 antennas (the Hi-Z Pro 8
element), the base of these acts as the ground rod. The soil conditions I had 
to put the bases in are markedly different from one another. Some of the bases 
are definitely in good soil but several of them are in such impossibly rocky 
ground that it took dozens of tries to get the rod 2' deep & with that, they 
were surrounded by stones from the top, down and there's very little soil 
around them.

I'm wondering if anyone has had a poor
location for active antennas like these and used something like Epsom salts to 
help get a better ground.

If so, did it help you & how did you find it helped?

How did you apply it?

Thanks & 73,

Gary
KA1J

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Topband: FW: Hi-Z Around Trees

[Lee STRAHAN]

  Greetings Top-Banders, I have been away for a couple days, sorry for the late 
comments.
The fact is, for me there is no definitive answer to the effect of trees on 
the Hi-Z arrays. I have made tests measuring phase shifts and amplitude changes 
with a variety of objects around these elements. My original thoughts after the 
tests were that any tree or large foliage would have to a minimum of 5 feet 
distance from the elements. There are not many trees where I live so this sort 
of test is very difficult. One of the things I did was to measure the 
capacitance of the elements as a source impedance to the amps. Changes in this 
capacitance would make amplitude changes at the amplifiers. The only real 
changes I measured after numerous tests were when I would approach the element 
with the capacitance meter in operation. When a 6 foot person approached the 
elements I could see changes in the element at about 3 feet separation. Nothing 
at 5 feet. This was with a 24 foot aluminum element and a low capacity mounting 
insulator. This capacitance test was more sensitive than my voltage and phase 
measurements.
   Mike NI7T installed a 4 square system in the forest behind his cabin. Many 
pine and redwood trees were within 5 feet of the elements. We were never able 
to discern any negative affects to his array. Front to back rejection was well 
within nominal and front patterns seemed proper. The array remained sensitive 
to weak signals. Larry K1UO had his array in a brush patch. As I recall I 
suggested a 5 foot spacing which he did. If you have not seen the DX Larry 
posts from Maine you are missing something. In other words it was apparently 
adequate spacing.
   So with the 24 foot elements ¾ inch diameter that have around a 75pf source 
capacitance I would say you are pretty safe at 5 feet. Shorter elements with 
significantly less source capacitance would surely need more spacing. A 12 foot 
similar element drops clear down to 42pf source capacitance. I would hazard a 
guess that arrays using short whip elements at around 25pf would be quite 
sensitive to close trees or foliage.
Barring all this I am confident you would be absolutely safe in my 
estimation at 10 feet distance of brush, tall foliage, and trees from the 
elements.

Lee  K7TJR

>>Hello Jim

My HI-Z 4 square has trees about 15 feet away from two of the elements (I can 
make exact distance measurements if that would help you).

I do not "think" the trees interact in my setup - but I am not 100% sure. Even 
my HI-Z 8 circle has trees pretty close to 3 elements (10 feet). Without 
measuring changes (impedance) to these elements due to location, I am not sure 
how else to know. However, given Frank's comments - I will be trimming some 
trees today!

I am certain K7TJR is the expert on this has he has heard from users about 
element location and performance for years.

I wish you the best.

73
Tim K3LR


From: donov...@starpower.net 
[mailto:donov...@starpower.net]
Sent: Saturday, November 12, 2016 6:57 PM
To: j...@audiosystemsgroup.com
Cc: Lee K7TJR; k...@k3lr.com; Joel Harrison
Subject: Re: Hi-Z Around Trees

Hi Jim,

My comments about short verticals not performing well near trees
applies only to high impedance verticals.   Low impedance are
little affected.

73
Frank
W3LPL


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Re: Topband: 60' or 70' spacing on Hi-Z 4/8 element RX array

[Lee STRAHAN]

   Gary and others,
   As I said losing 6 dB + on the 4-8 Pro by going to the smaller diameter 
array down to 84.84 feet in diameter will be no problem whatsoever. There are 
still many users using the arrays with the original Hi-Z amps which had a loss 
of 6 dB. You are using amps with 6 dB more gain than those.  In addition there 
are several systems operating that use my dual band dual direction system. This 
system loses another 3 dB of signal by splitting the signals to two combiners.  
So, there are proven stations using the same combining system with much less 
available system gain. I know for a fact they are hearing very well into the 
noise. Especially on the system with the dual directions. He is a contester and 
always on top of the heap. This user is still using the older style of amp with 
6 dB of loss and the dual direction system with another 3 dB loss.
   113.12 feet diameter or 80 feet on a 4 square side  and 84.84 feet  diameter 
or 60 feet on a 4-square side are the only two stocked by DX Engineering.
  Any other size systems would need a different set of delay cables.
   Fear not Gary, Just cut your element cables for the widest spacing you think 
you could ever use and then all you would have to do is move the elements and 
change delay cables if you were still curious.
 You will not be able to tell the difference between your ears. 
   The 84.84  foot system greatly improves 40 meters with only approximately a 
0.2 dB loss in RDF on 160 meters. My original design goal was based on maximum 
RDF on 160 meters period. Then the narrow spacing came later. I originally did 
not expect I could get system accuracy good enough for the narrower arrays. It 
paid off to pick the fly poop out of the pepper ( an engineering term) during 
the original design as it ended up easily having the accuracy to implement that.

 Lee  K7TJR



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of StellarCAT
Sent: Wednesday, November 02, 2016 10:26 AM
To: n...@yahoo.com; topband@contesting.com
Subject: Re: Topband: 60' or 70' spacing on Hi-Z 4/8 element RX array

Thanks Bob,

70’ is what Lee use to offer ... I had a 4 sq with those dimensions (it was 
stolen out of a self storage unit however). I believe Lee would do cabling for 
either 70’ or 60’. My main focus is still 160 with 80 as the second ... but I 
don’t want to neglect 40 as spring/summer/fall static can be horrendous. So the 
total power isn’t an issue? please explain to me what exactly it means! So 
ALL signals – noise and signal are reduced by this same amount – 6.6 db? And 
assuming the preamp doesn’t add any noise then it would be – the same? 

or put another way – say I have 2 of these – an 80’ on a side and a 60’ on a 
side ... at the same location (but not interacting, or I can magically swap 
them out)... what if any change is there in the headphones?! That to me is the 
bottom line and what I’ve just not had an answer on yet. 

g.




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Re: Topband: RX ant-Frozen ground

[Lee STRAHAN]

When we at Hi-Z see deterioration it is often the output cable running to the 
receiver where the typical aluminum shield no longer makes great contact. Also 
if it's one of the Hi-Z Antennas amplifiers make sure you are seeing 4 to 5 
Volts DC at the element or amplifier input. Foliage touching an element has 
often been the culprit as well. Once even a spider crawled across the amp 
terminals and the 5 volts killed it and left a partial short.  You just never 
know.
Lee  K7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of VE6WZ Steve
Sent: Wednesday, December 07, 2016 1:36 PM
To: topband@contesting.com
Subject: Topband: RX ant-Frozen ground

I’m wondering what experiences are out there regarding small vertical array, or 
beverage performance in the winter over frozen ground.
 
The reason for this question is that over the last 2 weeks or so, my HI-z (24’ 
vertical) SDR skimmer antenna at my remote QTH has shown somewhat diminished 
performance and a dramatic increase in AM inter-mod byproducts on 160.
During the somewhat hasty install of this antenna (the SDR “RBN skimmer” 
antenna was not considered an important part of the station) I had some trouble 
driving the ground rod for the HI-z amplifier and only ended up with about 3’ 
of copper pipe driven into the ground. During this past summer and fall the 
performance was good.
Winter has been here for a while. Last night it was -28 deg C. Today, that rod 
is now probably sitting in a block of solid ice. (ok, not solid ice, but the 
conductive dissociated ions from the native salts distributed within the soil 
are now locked in ice)
 
In truth I am not really concerned about this particular antenna, but I do plan 
to install an 8 circle array as well as some beverages  this summer and this 
problem got me thinking about making sure I have a “seasonally stable” ground 
system up here in the frozen north.
Some quick research points to potential frost depths ranging from 6’-8’ 
depending on snow cover and soil type. Perhaps driving deeper rods could help, 
but it seems to me that there will still be a seasonal change of consequence. 
Literature associated with various short vertical array products indicate that 
3’-4’ rods should be adequate, but is this true in a northern climate?
For the most part, I could care less whether the array works in the 
summer…..it’s during our winter DX season that I want performance.
 
Perhaps a very carefully designed and symmetrical short ground radial system 
could stabilize things, but I know with phased rx vertical arrays this can be a 
big problem and cause phase imbalances. Perhaps on my beverages a small radial 
system at the termination would be helpful.
 
I am not new to rx antennas, having built and used numerous single wire 
beverages, reversible beverages and end-fire phased beverages as well as 
passive and active (Hi-z) phased vertical arrays at my home QTH, but have never 
“noticed” a problem.
BTW, it is possible that there is something else going on with my SDR antenna 
other than a ground problem, and I will be checking that out next time I’m at 
the station. However,  I think I’ll still want to consider the frozen ground 
impact even if there is something else going on.
 
Any experiences, measurements or ideas from those living in places where it 
snows a lot, you have something called a “block heater” for your car, and when 
you work outside you last about 5 minutes before your hands and toes are numb??
 
de steve ve6wz. 

 
Steve Babcock
Lead Geologist, Mature
TAQA North Ltd.
D +1.403.724.5147
M +1.403.870.0082
2100, 308 – 4 Avenue SW, Calgary Alberta Canada T2P 0H7


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Topband: ARRL 160

[Lee STRAHAN]

Just a note that I have unclaimed the 4M1K QSO from my official log in the 
contest.
My question on the reflector appeared as assistance to some in the contest. And 
rightly so.
The ARRL submission AP tells you to correct the mistakes rather than remove or 
unclaim them and that is NOT RIGHT!

Lee K7TJR  OR
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Topband: ARRL 160

[Lee STRAHAN]

   My apologies to all the EU stations that tried to call me in the ARRL 
160 contest. I have received several e-mails and comments
on the KST chat about that. (No Ears).
I have a new wood products plant that has moved in next door to me and has 
raised the noise floor to Europe and North
by more than 20 dB. I am in the process of solving this problem so I can get 
back with Ears that direction. In the mean
time I am sorry I was an alligator that direction. I luckily still managed 14 
countries in other directions.
  Lee K7TJR  OR
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Topband: ARRL 160

[Lee STRAHAN]

That's all OK Ward but the guy on the other end will not get credit for the 
correct QSO. Not right also.
 I chose to mark the QSO as unclaimed as that hopefully will deal with it 
correctly?
Lee  K7TJR  OR

>>
If the web upload app for log submission finds something in a QSO: line it 
can't deal with...

 > The ARRL submission AP tells you to correct the mistakes rather than remove 
 > or unclaim them and that is NOT RIGHT!

Point of clarification - the app does not really know anything about a 
particular call.  It just knows that the data it found in what it thought was a 
call sign field did not look like a call sign.  (You would get a similar error 
if the Sent Call data is bad or the RST isn't an
RST.)  It is up to the log submitter as to what to do about that.  If the QSO: 
line is just mis-formatted, rearranging the information to satisfy the Cabrillo 
format is perfectly OK.  If the call sign is busted (from typo, mis-copy, or 
whatever), my suggestion would be to remove the line entirely.  Same thing if 
the the section abbreviation is not valid.

73, Ward N0AX
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Topband: ARRL 160

[Lee STRAHAN]

   H, Writelog lets you think you have marked a QSO as unclaimed when you 
ask it to export a Cabrillo file.
Thanks for the update Tree.
Lee  K7TJR
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Topband: ARRL 160

[Lee STRAHAN]

   Did anyone else work the station IDing as 4MJK?
The ARRL robot will not accept that call sign. I was pretty sure I had it right.
Lee K7TJR  OR
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Re: Topband: ARRL 160

[Lee STRAHAN]

   Bingo you guys are great. One little Dah.
TNX Lee

   Did anyone else work the station IDing as 4MJK?
The ARRL robot will not accept that call sign. I was pretty sure I had it right.
Lee K7TJR  OR
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Re: Topband: 4sq receive antenna side filters?

[Lee STRAHAN]

Grant, and others.
It is sort of possible to filter high impedance type RX 4-squares. The 
source impedance of a 2 foot long 1 inch dia. tubing vertical is a  few ohms 
resistance depending on the ground situation and approximately a 60 picofarad 
series capacitance. For the Hi-Z systems the amplifiers, their input impedance 
is approximately 43Kohms parallel with ~15 picofarad. I cannot speak to the DX 
Engineering 4-square values, only the Hi-Z systems.
   We have routinely supplied filter sets for the front end of the Hi-Z systems 
that work for the reduction of broadcast AM frequencies with a notch. They all 
have to be carefully matched components so the system phasing is not disturbed. 
There is no known degradation of the system performance using these filters.  I 
am also aware of a high pass filter system that is in use at a contest station 
that provides attenuation of frequencies above 40 meters also at the high 
impedance level. 
   I do not know of any single filters that would operate well without 
switching for different bands. I believe that it may be possible to build a 
switchable system that could provide your 40 dB of rejection of a lower band 
frequency band than the band operating on.   
   If you would like to discuss this in detail please e-mail me at 
k7...@msn.com and we can set up a telephone session or e-mail exchanges. I 
would be happy to share my work with you.
Lee  K7TJR   OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Grant Saviers
Sent: Monday, September 11, 2017 7:26 AM
To: topband@contesting.com
Subject: Topband: 4sq receive antenna side filters?

I was asked by a DXpedition leader if it was practical to bandpass filter the 
input (antenna side) of the DX Engineering 4 sq's they plan to use (I have 
one).  Given the few acres of the island and 5 feet ASL there isn't space to 
get adequate antenna separation and of course both transmit antennas are 
verticals.  The concern is with QRO transmitters on 160 and one on 80m at the 
same time that the coupling will cause 
overload and IM.Beverages would not work above the salt water 
intrusion.  A direction switchable DHDL is planned for 40m.

Any thoughts on if this is possible, been done before, or how to do it?

A deeper question is what impedances are possible for a 20' whip and the input 
of the amplifier for a filter design?  Sacrificing noise performance, some 
gain, and frequency range are all reasonable to solve the problem.  Probably 
more than 40db of rejection is needed. Switching a pair of filters with an 
outboard box on each whip looks to be the easy part.

Grant KZ1W
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Re: Topband: 160 4 square

[Lee STRAHAN]

 Hello All
JC, Greg knows quite a bit about receiving on 160 meters as he has had a 
Hi-Z 8 element array for some years now. Actually he has done quite well with 
it. Especially when he was neighbors with our dear departed friend N4NN in 
Florida.
   JC, I have a question. If the Waller flag does not respond to vertical 
signals why do you have to detune your vertical tower? The second part of my 
question is if you do not have any local power line noises covering vertical 
signals what advantage would a horizontal RX antenna be?

LeeK7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC
Sent: Sunday, August 27, 2017 8:05 PM
To: 'GaryK9GS' ; 'Greg' ; 'topband' 

Subject: Re: Topband: 160 4 square

HI Greg

You need to detune the tower and the 4 square will work fine. But if you want 
to have a good RX you need a Horizontal Waller Flag at 140ft or more.

You can  see the two webinars about Waller Flag at  www.wwrof.org archives

http://wwrof.org/webinar-archive/n4is-waller-flag-construction/

http://wwrof.org/webinar-archive/high-performance-rx-antennas-for-a-small-lot/

Doug NX4D 160m DXCC is # 304 confirmed, from a 1/5 acre lot, I started 3 years 
later with a Waller Flag and am at #293 confirmed. I sure mist a 4 square for 
TX ,. because since 2006 I've heard 316 countries on 160m from my acre city lot 
in Fort Lauderdale on the last 10 years. 

Noise is very high here on the city

The best way you can destroy the station for RX on low bands is to use elevated 
radials and NOT DETUNE IT during RX. 

The concept is  simple! All your wires makes only one receiving system. It is 
necessity to keep all of them clean.

Performance is subjective, if you have nothing to compare you never know what 
you are missing.

If you listen only vertical you are missing 50% of the band.

Regards
JC
N4IS
 

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of GaryK9GS
Sent: Sunday, August 27, 2017 5:51 PM
To: Greg ; 'topband' 
Subject: Re: Topband: 160 4 square

Take a look at the K3LR website.  This is essentially what Tim does, only 
instead of a 4-square, his array is a 5 element parasitic array with three 
active elements.  K3LR just gave a presentation on his station this weekend for 
the Society of Midwest Contesters and this was mentioned.


73,
Gary K9GS
 Original message From: Greg  Date: 
8/27/17  1:56 PM  (GMT-06:00) To: 'topband'  Subject: 
Topband: 160 4 square Question for the group...

>From a 140 foot freestanding tower, I will suspend 4 pieces of phillystran
90 degrees apart from the top of the tower.  Antenna wire will be attached to 
the phillystran such that verticals will be dropped to create a 4 square.
I will have as much vertical length as practical and still obtain the 4 square 
spacing required -- but the vertical length certainly will not be close to a 
quarter wave.  The intent is to use the verticals as a 4 square.
In thinking of ways to increase the electrical length, should I run wire back 
toward the tower from the top of the vertical section to get the full
1/4 or use a T with wire going back toward the tower and down the phillystran 
to create a "top hat" effect -- or does it matter?  Obviously this is a 
compromise but hopefully still an effective antenna with directional gain.  
Thanks in advance for your thoughts.  73, Greg-N4CC _ Topband 
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Re: Topband: 160 4 square

[Lee STRAHAN]

   Good morning all,
  What I can tell you about the two antennas for 160 meter receiving is 
that as many have said before, you cannot have too many receiving antennas for 
160 meters. Before Dale N4NN became ill and passed, Dale and I maintained near 
daily contact. Dale had the Hi-Z 8 element with very little local noise. We 
always quietly compared his station with what you were reporting JC. As near as 
I could tell in the Florida area the two antennas were very close to each 
other. Most often both antennas would hear the same signals.
  There are a couple more contest stations that actually have both a horizontal 
Waller flag and a Hi-Z 4-8pro or 8A 8 circle. In one case the verticals are the 
preferred and in the other the word is you need both antennas. My opinion, I 
think it depends quite a bit on station location. That is, I think on stations 
near the ocean coasts the horizontal Waller flag hears very well. Again, my 
opinion but I don’t think it works as well in the mid lands or receiving over 
long stretches of land. Eventually we will have enough history to really know 
for sure if one or the other is better. Again, there is likely advantages to 
either one at different times or locations. Suffice to say there is lots left 
to be learned
In that regard, some stations have reported the Hi-Z full sized 8 circle to 
not quite have enough sensitivity in really quiet background noise areas. I 
have developed a means to reduce the noise figure of that array very 
significantly and the first beta test users are reporting a definite 
improvement to the standard Hi-Z 200 foot 8 circle on 160 meters for those 
fortunate enough to have a really quiet location.
Lee   K7TJR

From: Bob Kupps [mailto:n...@yahoo.com]
Sent: Monday, August 28, 2017 5:58 AM
To: JC <n...@comcast.net>; 'Lee STRAHAN' <k7...@msn.com>; 'GaryK9GS' 
<garyk...@wi.rr.com>; 'Greg' <n...@windstream.net>; 'topband' 
<topband@contesting.com>
Subject: Re: Topband: 160 4 square

Well I ordered one about half a year ago so if it ever comes I will be able to 
compare it directly with my HiZ 8 circle array and get a definitive answer. We 
have no local noise here only propagated tropical QRN.

73 Bob HS0ZIA
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Re: Topband: Best Receive Antenna over Sloping Terrain?

[Lee STRAHAN]

   Greetings Topband antenna guys,
 As a manufacturer of shortened vertical element receiving antennas, I have 
been asked the question about sloping ground many times.
It occurred to me one day that I could use Eznec to solve the question. What I 
did was to slope the elements with respect to Eznec zero elevation and made the 
angle of the elements to the ground the same as if the earth under your sloping 
antenna field suddenly went flat and the elements were then leaning. I lean the 
verticals in Eznec to the angle offset of the questionable uneven earth.
   It is not too hard to program these angles into Eznec and then when you view 
the resultant plot you can turn your head or viewing angle so that the plot 
zero elevation is at the slope angle or if you have any vertical elements you 
simply view it at an angle where the vertical portions are vertical in your 
view.
   It is a little hard to describe this but starting with a single vertical 
element should help to understand the process.
  What I found generally was that the patterns of the vertical antennas or 
the take off angles mostly simply followed the rising ground and the pattern 
stayed mostly the same up to a point where the difference in height of the 
verticals was about 1/3 of the height of the element.
   I suspect Eznec could easily be used on other style antennas like Beverages 
or loops, etc. using my technique with Eznec.
  Your results may vary . I have not tried other style antennas except 
shortened verticals. I would be interested in hearing results if someone tries 
this.
Lee   K7TJROR
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Re: Topband: BOG pre amp info ?

[Lee STRAHAN]

 Hello Tim and all.
 The input impedance of the W7IUV amp is also highly dependent on the 
negative feedback found by looking at the unbypassed base bias circuit. And 
highly dependent on the size of the unbypassed emitter degeneration resistance.
There is a thorough discussion of this by Wes W7ZOI in the ARRL book 
"Experimental Methods in RF Design". 
Lee   K7TJR   OR

>Input impedance on the W7IUV preamp is determined almost entirely by the DC 
>bias currents.

>Clifton Labs used to have a really nifty set of pages on modeling and 
>measurement of the various high performance preamps. I really miss that site.

>Tim N3QE

On Mon, Nov 27, 2017 at 9:46 AM, Roger Kennedy < ro...@wessexproductions.co.uk> 
wrote:

> Hi Don
>
> Gosh, really?  Looking at the circuit, and given the resistors used, I 
> would have thought the input impedance would be about 800 ohms . . .
>
> And hard to estimate the output impedance, but wouldn't have thought 
> it was about 50 ohms.
>
> Guess I'm wrong then !  Sorry about that.
>
> (I already built a FET pre-amp for my Loop . . . but was just 
> commenting.)
>
> 73  Roger G3YRO
>
>
>   _
>
> From: Don Kirk [mailto:wd8...@gmail.com]
> Sent: 27 November 2017 13:09
> To: Roger Kennedy
> Cc: topband
> Subject: Re: Topband: BOG pre amp info ?
>
>
>
> HI Roger,
>
>
> You said "However, the circuit seems odd . . . I used transformers in 
> and out on my Loop Preamp, to give a match to 50 ohms."
>
>
> I believe your above statement was in reference to the W7IUV preamp.  
> I've measured the W7IUV preamp input and output impedances and also 
> modeled the W7IUV preamp using LTspice, and both methods yield input 
> and output impedances of close to 50 ohms.  Therefore no additional 
> components (such as matching transformers) are required for impedance 
> matching purposes on the W7IUV preamp.
>
> Just FYI,
> Don (wd8dsb)
>
>
> On Mon, Nov 27, 2017 at 5:36 AM, Roger Kennedy 
>  wrote:
>
>
>
> That's a nice cheap board, and worth using considering it has relay 
> switching too . . .
>
> However, the circuit seems odd . . . I used transformers in and out on 
> my Loop Preamp, to give a match to 50 ohms.
>
> Roger G3YRO
>
> 
> ---
>
> Try this guy he does good quality boards and it's easier than 
> importing from the states,
>
> https://m.ebay.co.uk/itm/
>  PCB-for-experimenters-
> 2N5109-or-DCP68-transistor-/261634019988>
> W7IUV-Beverage-preamplifier-PCB-for-experimenters-2
> N5109-or-DCP68-transistor-/261634019988
>
> Trevor
> EI2GLB
>
> _
> Topband Reflector Archives - http://www.contesting.com/_ 
>  topband
>
>
>
> _
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>
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Topband: Big 160m openings just before K index spikes

[Lee STRAHAN]

  I have also seen big openings here in Oregon just prior to a big solar event.
If I recall correctly it was when I worked the A4 which is huge from the 
Pacific Northwest.
Lee   K7TJR
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Topband: FT8 - the end of 160m old school DXing?

[Lee STRAHAN]

   You guys should have been around for the AM versus SSB discussions/wars 
without the use of the instant communication internet.
Oh my,
Lee   K7TJR
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Re: Topband: Any experience with 2N3553?

[Lee STRAHAN]

Thanks Tony,
   Agreed the 2N5109 will be around for a long time however as you point out 
they are or will be very expensive. At present I use 100's of 2N3866 
transistors which are very close to the same die if not selected from the 
2N5109 process. My cost in 100 quantity has gone from about $1.60 each to 
currently $4.00 each in about 2 years' time for 2N3866's. The 5109 is currently 
priced less at $2.22  where the 3866 used to be less. From all this I conclude 
that the 2N5109 will follow the huge price increases. I could be wrong but I 
will not plan on using the 5109 especially where most things are going to 
surface mount also. Even J-310 FETs have gone from <$.20 to $2.41 at 100 level. 
Worst thing is 20% of the off brand j-310s don’t meet spec. The only way to 
solve this is to go to surface mount where you can still get the good J-310 and 
other great devices. One can often use more than one SMD device in an amplifier 
having it cost less than one expensive leaded  device. For the hams building a 
single amplifier the 5109 makes a lot of sense right now. Semiconductor times 
are changing rapidly. I make lots of top-band antenna systems using lots of 
already expensive electronics. For this reason I have to do as well as I can to 
predict the future for my products. My observation is that leaded parts are 
disappearing rapidly and this will continue.

LeeK7TJR
Hi-Z Antennas

-Original Message-
From: N2TK, Tony  
Sent: Sunday, July 1, 2018 2:03 PM

To: 'Lee STRAHAN' ; mar...@ok1rr.com; topband@contesting.com
Subject: RE: Topband: Any experience with 2N3553?

The 2N5109 will be around for many years. It is widely used in the military and 
space community.  It is listed as a JAN part. But it ain't cheap.
73,
N2TK, Tony

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Lee STRAHAN
Sent: Sunday, July 01, 2018 2:15 PM
To: mar...@ok1rr.com; topband@contesting.com
Subject: Re: Topband: Any experience with 2N3553?

Hello Martin and all,
The 2N3553 device was plagued with a low Ft (high at its introduction)  
making it mostly a low frequency device with questionable high gain high 
frequency use in typical ham preamps. It is no longer available through the 
original manufacturers. Also perhaps you are thinking of the BFQ18A and not the 
BFQ19A device. The BFQ19 is at end of its life cycle and in addition the 18A is 
widely used now in the MATV industry for wideband amplifiers. I have some 
experience with the 18A using it in a wideband Norton style amplifier where it 
is providing 10+dB of gain with a measured noise figure of 2 dB on 160 meters. 
Its typical IMD is at least listed at UHF on the data sheet. My IMD testing 
setup is not adequate to test the range of this device but I can say that it 
exceeds any other amplifiers I have built to date. I typically use the 2N3866 
which unfortunately is pricing itself out of the market now. I suspect the 
2N5109 will follow as inventories shrink.. A pair of the 18A devices at ~$1.00 
USD each single price in a push pull Norton configuration would in my opinion 
make it worth trying as a killer wideband amp. 
Just my $.02 USD.
Lee   K7TJR  OR

-Original Message-
From: Topband  On Behalf Of Martin Kratoska
Sent: Sunday, July 1, 2018 9:51 AM
To: topband@contesting.com
Subject: Topband: Any experience with 2N3553?

The 2N3553 is a brutal 7 watt device in a TO-39 metal package. Chris Trask, 
N7ZMY mentioned some unparalleled IM characterics

'... The BFQ19 (made by NXP née Philips) and the NE46134 (made by NEC) are both 
highly popular within the CATV industry, and are virtually identical in terms 
of linearity. They compare favorably to the 2N5109 in terms of linearity, 
though they pale in camparison with the 2N3553 (as do all the others)...'.

See
http://www.home.earthlink.net/~christrask/Bipolar%20Transistor%20Evaluation.pdf

2N3553 is often mentioned in transmitting applications but I was unable to find 
some other details like IM, noise and gain characteristics in high DR preamps 
for receiving purposes. Any experience?

73,
Martin, OK1RR
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Re: Topband: Any experience with 2N3553?

[Lee STRAHAN]

Hello Martin and all,
The 2N3553 device was plagued with a low Ft (high at its introduction)  
making it mostly a low frequency device with questionable high gain high 
frequency use in typical ham preamps. It is no longer available through the 
original manufacturers. Also perhaps you are thinking of the BFQ18A and not the 
BFQ19A device. The BFQ19 is at end of its life cycle and in addition the 18A is 
widely used now in the MATV industry for wideband amplifiers. I have some 
experience with the 18A using it in a wideband Norton style amplifier where it 
is providing 10+dB of gain with a measured noise figure of 2 dB on 160 meters. 
Its typical IMD is at least listed at UHF on the data sheet. My IMD testing 
setup is not adequate to test the range of this device but I can say that it 
exceeds any other amplifiers I have built to date. I typically use the 2N3866 
which unfortunately is pricing itself out of the market now. I suspect the 
2N5109 will follow as inventories shrink.. A pair of the 18A devices at ~$1.00 
USD each single price in a push pull Norton configuration would in my opinion 
make it worth trying as a killer wideband amp. 
Just my $.02 USD.
Lee   K7TJR  OR

-Original Message-
From: Topband  On Behalf Of Martin Kratoska
Sent: Sunday, July 1, 2018 9:51 AM
To: topband@contesting.com
Subject: Topband: Any experience with 2N3553?

The 2N3553 is a brutal 7 watt device in a TO-39 metal package. Chris Trask, 
N7ZMY mentioned some unparalleled IM characterics

'... The BFQ19 (made by NXP née Philips) and the NE46134 (made by NEC) are both 
highly popular within the CATV industry, and are virtually identical in terms 
of linearity. They compare favorably to the 2N5109 in terms of linearity, 
though they pale in camparison with the 2N3553 (as do all the others)...'.

See
http://www.home.earthlink.net/~christrask/Bipolar%20Transistor%20Evaluation.pdf

2N3553 is often mentioned in transmitting applications but I was unable to find 
some other details like IM, noise and gain characteristics in high DR preamps 
for receiving purposes. Any experience?

73,
Martin, OK1RR
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Topband: My beverage only hears static?

[Lee STRAHAN]

Hello All,
I may not have seen all of the posts on this topic but will comment anyway.
   Two things come to mind about this noise. Number one is you do not want to 
connect the shield of the coax going to the receiver to the ground stake for 
the antenna. It's important that the transformer you use has an isolated 
winding for the output to the cable leading to the shack. The other comment is 
you may have some local  arcing or digital noise that the Tx antenna does not 
hear. The best clue to checking for this is to use the AM mode on your receiver 
and listen for the characteristic hum from a power line or switching supply.
   Good Luck
Lee   K7TJR  OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of terry burge
Sent: Saturday, January 13, 2018 11:09 AM
To: David Olean ; topband@contesting.com
Subject: Re: Topband: Topband Digest, Vol 181, Issue 16

Hello Dave and Group,


I had responded directly to Martin and will include my comments to him. Right 
now I hesitate to pull the tape off the coax at the XFRM but will do that ASAP 
to check it out. When I took it off the old spool it had not been used but it 
is donated to me from a junk yard lot. I also got a 4 foot spool nearly  full 
of 1/2" hardline I'm planning on replacing my  ground run of LMR-400 with. 75 
ohm but it should work if I can build the connections to the LMR-400 PL-259's, 
etc. 


Disconnecting the ground as well as the BOG (in this case) from the XFRM causes 
the noise to drop down to about S-1 to S-2. 

With ground connected to the XFRM I get about S-5 noise level without any 
antenna. 

Per my note to Martin you can read my other test. Right now with the  550-600 
ft. beverage hooked up along with ground of course, I get S-5 noise level and 
can't hear an S-9+10 over signal on  7.235 Mhz. 


Terry

KI7M



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Topband: Conditions on 160m for ARRL Contest

[Lee STRAHAN]

  For any that are interested there is now even a Hyperfix wiki page where you 
can hear a spot on recording of this system.
The loudest one here is near 1813KHz.
https://www.sigidwiki.com/wiki/HyperFix
Lee   K7TJR   OR
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Re: Topband: Conditions on 160m for ARRL Contest

[Lee STRAHAN]

   Mike and others,
   Those signals are NOT fishnet beacons. They are as one here said a version 
of a navigation system similar to Hyperfix. The reason you hear three "dings"
Is that there are three transmitters for each one that transmit in sequence and 
the electronics aboard ship measures the time of arrival for each pulse 
providing harbor navigation.
  How do I know this, I have heard them from the NW  here in OR many times and 
looked them up years ago. There have been at least two discussions about this 
here on top-band reflector over the years. And as mentioned they NEVER ID. They 
are also low power.
Mike I would suggest you Google Hyperfix.
   Lee   K7TJR  OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike Waters
Sent: Monday, February 19, 2018 5:09 PM
To: topband@contesting.com
Subject: Re: Topband: Conditions on 160m for ARRL Contest

Google *fishnet beacons *and educate yourself, gentlemen! :-)

73, Mike
www.w0btu.com
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Topband: test please ignore

[Lee STRAHAN]

Test email please ignore.
Thanks, Lee  K7TJR  OR

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Re: Topband: making a bev seem longer

[Lee STRAHAN]

Hi JC,
   Not all vertical arrays are mono band. A well built 4-square on a 60 foot 
per side can do a stellar job on 160, 80, and 40 meters while extending well 
down into the broadcast band. The 3 element as well as the 4-square based 8 
element on an 85 foot diameter circle will do the same thing.
Lee   K7TJR

>>

A BOG is an excellent choice when stealth is the driving requirement, otherwise 
arrays of short verticals provide significantly superior performance compared 
to BOG or short Beverage occupying the same physical space. 
<<

Hi Frank

Any particular reason you don't mentioned FLAG's, or EWE's?

Flags are easy to feed, they are broadband and have the same RDF directivity on 
160,80,60,40 and very usable on 30m. 4 Phased Flags fit on 150ft and outperform 
a pair of phased 1000ft long beverage. The  vertical flag has a low take off 
angle excellent for DX, 20 degree elevation lobe, and a beverage has 40 degree. 

Also you can turn a Flag array in all directions and a beverage is fixed in one 
direction, and when you decrease the frequency the front lob become so narrow 
that makes useless on 40 and 30m.

Vertical arrays are mono band. You need one for 160 , another for 80, and if 
you want 40 and 30 two more. Also they needs a lot of phasing cables and a 
large real state area far from constructions.

What am I missing here?

Regards
JC
N4IS

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Topband: Beverage transformers that work down to 630 m

[Lee STRAHAN]

Greetings Top Banders,
   Well we cant all agree on a 4X transformer primary rule. It depends on what 
you want to do with the transformer. In this case a Beverage for 630 meters. 
Driving on with the 4X rule will make you think all is well until you decide 
one day to add a second Beverage and try to phase them. The phase relationship 
between the two different Beverages will be somewhat dependent on the AL of the 
transformer cores when using too few turns. AL is not guaranteed or for that 
matter very temperature or unit to unit stable. When using transformers for a 
single system a few turns will work well providing small signal losses. One 
must thoroughly check transformer phasing especially when phasing 8 antennas 
together like the Hi-Z 8A receiving antenna. Different cores have different 
phase and amplitude responses including toroid and binocular when used in 
different circuits such as a Magic Tee & impedance transformation.
So don't be tripped up by a hard and fast rule unless you are using a 
transformer in a single antenna use.
 I recently ran some VNA plots on the Hi-Z 50 to 75 ohm transformer. I tested 2 
of them back to back using the 50 ohm ports of a VNA.
The results were, and remember a single transformer will have 1/2 of the values 
below that I measured for 2 back to back transformers.
These transformers are made as an autotransformer where the primary is 4 turns 
on a BN73-202 core with another turn added to the 4 for a 4 to 5 turns ratio. 
Yes, its 50 to 78.1 ohms as close as you can get with a small number of turns. 
Too many turns and you lose high frequency response.
100KHz-1.12 dB  at +25.9 degrees phase shift
600KHz   -.15 dB at +3.3 degrees phase shift  some 4 degrees off values at 
160 meters.
1.6 MHz  -.22 dBat -0.77 degrees phase shift
7.1 MHz  -.29 dB   at -9.0 degrees  phase shift
Remember single transformers are 1/2 these values.
Single antenna losses only are quite acceptable at 630 meters and 4 turns 
primary on a BN73-202 as loss wise one transformer is down less than 1 dB at 
100 KHz. 

 Lee  K7TJR  OR


-Original Message-
From: Topband  On Behalf Of Chuck Hutton
Sent: Sunday, July 15, 2018 5:49 PM
To: kd9sv ; topband@contesting.com
Subject: Re: Topband: Beverage transformers tht work down to 630 m

Yes, I think we all agree on the meaning of the 4X rule and the other basics.

The mystery to me remains that a 1 turn transformer was good to 270 kHz in the 
Clifton data. I calculate at 500 kHz:

1 turn on a BN73-202 with Al = 8500 gives 9 uH

9 uH is only 28 Ohms

For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242 Ohms.


So theory seems to tell me I need 3 turns.


Chuck




Guys, the 4x rule is to my understanding that the measured impedance at the 
lowest frequency to be used at should be at least 4 times the operating 
impedance.  In other words a 50 ohm system would require 200 ohms open circuit 
impedance measured at the primary winding of the xfmr.  If 2 turns only 
measures about 100 ohms then 3 turns would likely be close enough and 4 turns 
would also work and would measure 400 ohms which is 8 times the operating 
impedance of the antenna system.  My test equipment can only measure down to 
about 450khz so below that I cannot give an opinion.

73, de gary...ps: the BN202-73 will likely work well with two/6 turns and
3/9 for a 9:1 system for 50 ohms


Thanks for digging that out. It makes me worry much less about using BN73-303's 
with 2 or 3 turns in the primary at 630m.


My only problem is that I don't understand why the low end is so good for the 1 
turn primary. Using the "4x" rule for the transformer, 4 turns should be needed.

Since I don't understand the response and I don't care about the high end 
response, I'm still tempted to use 4 turns and be sure.


Perhaps part of the answer is that reality and theory do not coincide.
According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH and 
satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH.
That explains a good bit of the low end response.


Chuck




From: Tim Shoppa 
Sent: Sunday, July 15, 2018 3:50 PM
To: Chuck Hutton
Cc: topband@contesting.com
Subject: Re: Topband: Beverage transformers tht work down to 630 m

I agree the usual rule of thumb (Transformer winding Z should be several times 
larger than nominal line impedance) would cause you to think you should have 
more turns.

The old Clifton Labs website is no more. But an archived page of measurements 
of transformers shows that the frequency response extends well below what you 
might think, from the rule of thumb. Archived page:
https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Br
oadband%20Transformers.pdf
Clifton Laboratories 7236 Clifton Road Clifton VA 20124 
...
groups.io
Clifton Laboratories 7236 Clifton 

Re: Topband: Soil conductivity maps

[Lee STRAHAN]

Hello Jeff,
All those things you mention are great but times they are changing. You 
would be well advised if you find an interesting place to do a noise survey on 
and near the property. And consider what are the chances of urban sprawl to 
bring with it the latest scourge of a plethora of noise emitting switching 
devices. I am fighting one as we speak from a lumber mill making dimensional 
products that has moved in just across the street from me. Their fancy energy 
saving VFD drives has raised my noise floor over 20 dB on some areas of my 
property.
So consider this to be one of the biggest items on the checklist for a new 
site.
   Good Luck,
Lee   K7TJR   OR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jeff Kinzli 
N6GQ
Sent: Sunday, April 01, 2018 7:46 AM
To: top Band 
Subject: Topband: Soil conductivity maps

So I'm looking to purchase a new QTH. I'm not particular about location, but 
would like to optimize for soil conductivity and any other parameters that 
would increase near and far field propagation and minimize ground losses. I've 
seen the US Gov M3 maps, but they are very coarse. They also only define 
conductivity, and I'm wondering what other quantities would be useful to look 
at.

I know that a salt water takeoff or marsh is awesome, but that's not gonna 
happen in this iteration - looking very much central USA (W5, TX), inland.

So, any more fine-grained maps available? Or other quantities that would be 
worth looking at? Books that discuss this sort of thing?
Mostly for either pinpointing optimal areas, or making sure that a good looking 
property is at least half-way decent...

Thanks for any guidance,

de N6GQ
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Re: Topband: 160m polarization and elevation angles

[Lee STRAHAN]

  Jimmy Sullivan W7EJ  (SK) had a rotary dipole up for 160 meters at his CN2R 
station. You can still see the antenna as his CN2R site is still up. It came 
down in a wind storm in 2009, and I have no real knowledge of how well it 
worked but one might contact Dick W7ZR for information as he did some 
contesting from there. Also Jimmy's logs are still on site as well. A brief 
look showed it worked pretty well. Morocco is about 32 degrees North. YMMV
Lee   K7TJR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Thomson
Sent: Saturday, March 31, 2018 10:15 AM
To: topband@contesting.com
Subject: Re: Topband: 160m polarization and elevation angles

Date: Sat, 31 Mar 2018 23:15:00 +0800
From: "Steve Ireland" 
To: 
Subject: Re: Topband: 160m polarisation and elevation angles


http://www.contesting.com/_topband
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Re: Topband: HIZ 8 Circel Diameter.....

[Lee STRAHAN]

  Hello Frank and All,
  First you must tell us what you are expecting to make better with a Hi-Z 
array. Do you want Better front to back? Do you want Front to side? Do you want 
better signal to noise ratio? You want narrower beam width?  Not ALL things get 
better at once with size.
To my knowledge, with this phasing scheme  Just changing the spacing on 
your current 8A array will do more harm than good to the overall performance. 
The front to back will remain about the same. The front to side lobe will get 
severely worse to where the side lobes are only down about 8 dB. The RDF or 
signal to noise improvement of the 8A is the highest commercially available 
anywhere. It only changes 0.2 dB better theoretically going to 300 feet 
diameter. There is NO conventional wisdom that I am aware of that tells us the 
array should be better with a larger footprint. This array has ALL elements 
active all the time. Raising the foot print to 300 feet and going to 4 elements 
active per direction will only improve the front to side rejection but suffer 
from a 0.5 dB or so less signal to noise improvement. I could change the 
phasing on the 200 foot diameter array and lower the side lobes easily. I 
choose to stay with the higher RDF. 
   Theoretically it is possible to model 8 elements like this and get over 16 
dB of RDF ( I have the Eznec model) or signal to noise improvement. 
Unfortunately theoretics and reality  don't match. The current array from Hi-Z 
(8A) requires all of the transformers and components plus the cable lengths and 
element placement to be quite accurate (around 1% for each sub part) to even do 
the 13.5 dB of RDF. It is at this time likely NOT within a Ham budget to 
actually build an array accurate enough to even attempt getting more RDF or 
signal improvement out of 8 Elements with 8 directions. I even tried 12 
elements in 12 directions all active.
 There are installations using two arrays phased together to get 
approximately 3 dB  higher RDF. Even this is tricky but it is being done. At 
this time phasing two or more arrays has the best chance. First we know the 
smaller arrays work but can be affected by other antennas and power lines etc. 
A higher RDF array gets affected by the same things only worse. So phasing two 
arrays that are not affected as bad have a better chance of working in the 
environment than a single SUPER RDF array.
  Now,  If it seems your 8A only array just simply does not have enough 
gain or the noise level from it remains extremely low because of your low noise 
area contact me directly as we have a pilot program going on right now that 
reduces the Noise figure of this array by nearly 9 dB. Its not really simple 
but it works. This does NOT change the lobes or front to back or anything about 
the patterns only  the VERY  VERY weak signal performance.
  I get questions all the time about; can I make it better if I make it bigger. 
NO: if changing size would have been better I would have provided  it a long 
time ago. I have 100's of acres here to try things like that. I even looked at 
a 4-square of 8 element arrays. The beam gets so narrow you have deep gaps 
between the main lobe. 
   Ahhh so many antennas so little time.  Thanks for the question Frank, I hope 
this has been helpful.

73,   Lee K7TJR  Hi-Z Antennas.

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of 
dl8yhrfrank--- via Topband
Sent: Saturday, March 03, 2018 11:30 AM
To: topband@contesting.com
Subject: Topband: HIZ 8 Circel Diameter.

Hi everyone...
Did annyone has experience in using more wide spacing the 8 circel rx arrya?
Im running the hiz 8a lv2 160-2 arrya in a 200 foot spacing in the fields on a 
litel hilltop away from man made noise and have lots off space their so i think 
about to get it up to 300 foot spacing to optimize it for 160 Annyone tryed it 
ore can model it maybe if that will give more performace on 160?
Anny comments vy welcome
Best wishes
Frank
DL8YHR

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Re: Topband: 40m array as RX antenna

[Lee STRAHAN]

Hello JC,
There is nothing to disagree about JC, My 20 to 24 foot elements when fed 
into a Hi-Z amp produce a signal that is around 20 dB less than a good TX 
vertical. Your Waller flags produce a signal that is 40 to 50 dB below a TX 
vertical. What I said was that because of this difference in absolute signal 
level, Hi-Z systems could survive just fine in plastic boxes. Any other lower 
gain element certainly needs more protection like metal shielding, you are 
quite correct. I have a system I have been working on for years that falls in 
this same category of small signals that require more shielding. I do 
understand. Digging a weak signal is not a huge problem when you have 20 dB 
more signal to work with.
 I do not dispute what you say in regard to your Waller flag antennas. Do the 
plastic boxes let extraneous signal in? Yes but not enough to disturb the Hi-Z 
systems. And yes, circuit design is very important in both these cases. And 
yes, Hi-Z systems have internal common mode protection on various in and out 
connectors. They also have protection From signal injection from VCC. Plus a 
great deal more.
   I have no issue with what you say. I do not disparage your systems. I just 
don’t need the hundreds of Hi-Z customers calling about changing to metal boxes 
on my systems that won't be improved by this type of change...
  73 
Lee   K7TJR
Hi-Z Antennas



Hi Jim and Lee

Before we agree that we disagree, let me elaborate on few basic concepts for a 
good design. Point by point and let me know which one you disagree.

1- RF runs outside the cable surface, it does not matter what is inside, a coax 
cable shield, a solid # 4 wire external surface is similar to a RG58 in respect 
of RF current.

2- Every cable on your station is an antenna. If the cable is 1/8 to 1/2 wave 
long on low bands, the energy on the outside surface is very high. 100ft rotor 
cable , or 100ft 9913 from your 2m antenna, or 100ft of controls cable, and or 
100ft of RG6 on your RX antenna have almost the same energy of your 160m 
inverted L ~ 120ft.

3- All these cables somehow are connected to your station ground at your 
station. All of them are part of your antenna system and interact with each 
other.

4- Any of these cables connecting into a well-designed board brings a lot of 
energy on low bands, normally called common mode noise, signal that we don’t 
want to mix with our RX signal coming from our RX antenna.

5- Prevent the external RF current to enter into our board is a big problem on 
low bands. On Audio, you have an excellent description of pin 1 problem on your 
papers, 60 and 120 Hz is the issue. On low bands 1.8 MHz, all RF signals from 
50 KHz to 10 MHz are responsible for the common mode noise current on low band 
antennas.

6- To filter or decouple 1.8 MHz signal a 1000 pf or 1nF has a very high 
impedance, 10nF is not enough, it is necessary 100 nF or more. DC filter is an 
issue too, it is easy to inject the common mode noise into the Vcc.


7- May point is that is very difficult to protect any board or parts, like a 
BALUN or transformer, or any amplifier from common mode noise, PIN 1 PROBLEM.  
A plastic box make almost impossible to avoid that. A Metal case protects the 
board and avoid the external current to get into the board. 

8- I can agree that the intensity of the signal and the  common mode signal 
leak could be 20 db, 30 db or more. However when you dig a weak signal it is 
huge problem.

73'
JC
N4IS 






-Original Message-
From: Jim Brown [mailto:j...@audiosystemsgroup.com] 
Sent: Wednesday, November 14, 2018 8:10 PM
To: n...@n4is.com
Cc: l...@k7tjr.com
Subject: Re: Topband: 40m array as RX antenna

On 11/14/2018 4:41 PM, n...@n4is.com wrote:
> I would suggest a metal box to protect any RX system, it does help.

Only if the circuit layout is poor. Lee is right - shielding of circuity is 
only a band-aid for poor design.

73, Jim K9YC

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Re: Topband: 160m Condx

[Lee STRAHAN]

Just as a reminder to all that these BCI problems can also occur at 2nd and 3rd 
order IMD mixing.
Example 3rd order,  one station on 1220 where 2X equals 2440 and a second 
station at 620 subtracted puts a 3rd order product right on 1820 .
Another example 3rd order, is 2 stations at 600 where 2X equals 1200 added to a 
second station at 610 for a 3rd order product at 1810.
Second order is 1190 +620 is  1810 KHz   or 860 + 970 KHz is 1830 KHz
 These type of IMD products can be as a result from any amplifiers inline with 
the antenna and radio or even the radio itself mixing in nonlinear devices like 
BJT or FET transistors, even passive devices like transformers and crystal 
filters.
   This is directly related to the 3rd and 2nd order IMD specs on any 
particular piece of equipment.
  Sometimes these spurs are not just BC station harmonics.
Lee  K7TJR  OR

-Original Message-
From: Topband  On Behalf Of Lee. KX4TT via 
Topband
Sent: Monday, November 12, 2018 10:58 AM
To: 'Mike Waters' ; ve...@shaw.ca
Cc: 'topband' ; 'Filipe Lopes' 
Subject: Re: Topband: 160m Condx

Concur . if a frequency either ends with a zero, or if you add the digits 
up and get a number divisible by 9, it will likely have a greater change for BC 
interference. 

Example in Tampa (Florida, US) is 1860, which is the 3rd harmonic for WDAE 620, 
which is a 50kW stn.  An example for our UK friends is 1818, which is the 2nd 
harmonic for 909khz (BBC Radio 5)

Great discussion!

73 de Lee KX4TT



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike Waters
Sent: Monday, 12 November, 2018 13:27
To: ve...@shaw.ca
Cc: topband ; Filipe Lopes 
Subject: Re: Topband: 160m Condx

Perfect! Thanks for sharing.

73, Mike
www.w0btu.com

On Mon, Nov 12, 2018 at 12:13 PM VE6WZ_Steve  wrote:

> Know bad frequencies- great resource here:
> http://www.k8nd.com/TopbandBadFreqs.pdf
>
> However…a “best practice” on 160m is NEVER call CQ on an exact frequency.
> Why is it ever necessary to call on 1830, 1820, 1822 etc. exactly? 
> Call CQ on 1820.3, or 1820.4 or 1822.6 or 1827.8.
> Perhaps its human nature to want to use a nice “round” number, but 
> this accomplishs nothing except increase the chances of being on a harmonic 
> QRG.
> Its surprising how many DX-peds will do this too.  We don't need a 
> nice frequency with no decimal points! You will be found just fine 
> with all the skimmers and spotters out there.
>
> de steve ve6wz.
>
>
>
> On Nov 12, 2018, at 9:31 AM, Filipe Lopes  wrote:
>
> Hi
>
> Is there a listing of such frequencies? Want to avoid those in the 
> coming contests
>
> 73's Filipe
> CT1ILT CR5E CR6K
>
> Sent from my Huawei Mate 8
>
> Na(o) Seg, 12 de nov de 2018, 17:28, Mike Waters 
> escreveu:
>
> I wish we could get the word out to avoid frequencies like that: 1810, 
> 1820, 1830, etc. There are almost always AM BC harmonics on those freqs.
>
> 73, Mike
> www.w0btu.com
>
> On Sun, Nov 11, 2018 at 4:24 PM k1zm--- via Topband < 
> topband@contesting.com>
> wrote:
>
>
> Band still down a bit from last week but 4k6fo good sigs now on 1830.0 
> from Alim.
> 73 JEFF
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Re: Topband: Stew Perry Contest

[Lee STRAHAN]

If I was KH6LC I would be rather offended by that comment Bruce. What does 
it Really mean? Perhaps not what the words really say? KH6LC has more hard work 
in his station than many.

Lee   K7TJR   OR


-Original Message-
From: Topband  On Behalf Of F Z_Bruce
Sent: Monday, December 31, 2018 6:32 PM
To: g...@ka1j.com; Topband 
Subject: Topband: Stew Perry Contest



Sometimes someone will get lucky and get excellent 160 meter transmitting and 
receiving the first try. But most have to work at it  with  isolated 
directional receiving antenna (s), and  transmitting antenna(s) de-tuned while 
receiving. A antenna modeling program also helps. 

73
Bruce-k1fz
https://www.qsl.net/k1fz/beverage_antenna.html




On Mon, 31 Dec 2018 20:36:21 -0500, "Gary Smith" wrote:

Yes indeed, whatever he's using is
working. He copied me with my 5W signal
from Connecticut, 10 miles from Rhode
Island. Just got the LOTW today.

That is some more than excellent copy on their part for 160M.

73,

Gary
KA1J

> Nope, KH6LC doesn't have good ears, they have GREAT ears. Worked them 
> from MI with 5 watts and it wasn't the first time. HNYRuss, N3CO
>
> Sent from Yahoo Mail on Android
>
> On Mon, Dec 31, 2018 at 12:53 PM, Sam Josuweit
> wrote: Worked Hawaii from NE Pennsylvania with 100 watts. Still 
> smiling from that one. Thanks KH6LC good ears and great patience. Too 
> many people give up after one or two calls.
>
>
>
> Hope everyone has a Happy and Healthy New Year.
>
>
>
> Sam(N3XZ)
>
>
>
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Re: Topband: Info on modding 4 el HI-Z to 3 el HI-Z wanted

[Lee STRAHAN]

Hello Kevin,
   You would need to get a shack switch for the 3 element array and a phase 
controller for the three element. All the rest would retrofit just fine except 
you would have to contact me about the proper phase delay line to use with the 
three. Contact me directly if you need more information.
Lee   K7TJR   Hi-Z Antennas

-Original Message-
From: Topband  On Behalf Of kol...@rcn.com
Sent: Friday, November 30, 2018 9:23 AM
To: Topband@contesting.com
Subject: Topband: Info on modding 4 el HI-Z to 3 el HI-Z wanted


Anyone have any info? I have a 4 el unit but can only (maybe) accommodate a 3el 
triangle on my property. W hat would have to be done to the controller box 
etc.? 

73 Kevin K3OX 

- Original Message -

From: "Gary Smith" 
To: "Steven Jobes" 
Cc: Topband@contesting.com
Sent: Friday, November 30, 2018 12:15:21 PM
Subject: Re: Topband: Fwd: [yccc] Hi z receive antennas 

Steve, 

I haven't used the HI-Z 2 element or the JK system. I do have both the HI-Z 3 
and 8 element arrays. I find them both invaluable on 160 and 80. They do work 
on the higher bands as well, I usually use my triangular for 20M & up but I 
have only vertical antennas, no tribander. 

I can say that on a given 160 & 80 DX
signal, the 8 usually hears better than the 3 but not always, the 3 sometimes 
gets the best copy but always better by far than the sloper on 160 & INV-L on 
80. 

You'll never find better support than you get from HI-Z. 

73, 

Gary
KA1J 

> -Original Message-
> From: Steve via Groups.Io 
> To: yccc 
> Cc: yccc 
> Sent: Wed, Nov 28, 2018 8:51 pm
> Subject: [yccc] Hi z receive antennas
> 
> Hi I am seeking information from anyone with experience with hi z 
> arrays. I am considering either the hi z two element array or the Jk 
> antenna bev-flex beverage system. They both can fill my needs as my 
> property has limitations headed northeast. And both will give me 
> directivity towards Europe. Thanks for any advice,
> 
> 73 ,
> Steve Jobes
> W1dxh
> 
> -=-=-=-=-=-=-=-=-=-=-=-
> Groups.io Links: You receive all messages sent to this group. 
> 
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Topband: RCS8V is the correct model

[Lee STRAHAN]

   Hi Al and the group
 I was looking for an on to off isolation spec with the RCS8V coaxial 
switch but unable to find one. I have seen where two different receiving 
antennas will interact with each other if the isolation between ports on a coax 
switch is not great enough. They use a single relay so my GUESS would be about 
40 dB. This is why we developed the Hi-Z coax switches that will provide over 
70 dB of on to off ratio and isolation between inputs for little to none 
reaction between receiving antennas. You might contact the manufacturer for 
information on the isolation capability of their RCS8V product. Its not of much 
concern for transmitting antennas but certainly can be with receiving antennas 
with high directivity.
Lee   K7TJROR

Subject: Topband: RCS8V is the correct model

Had a brain fart here.  I meant to ask RCS8V and Gary KD9SV was kind enough to 
question my switch designation.
Best,
Al,  W5IZ
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Re: Topband: W7LR

[Lee STRAHAN]

Tree,
  Would you please pass along Bob W7LR's new address. Or a phone number if you 
have it. Bob and I corresponded regularly as he was one of the very first that 
I designed a receiving array for quite a long time ago. It was a broadside end 
fire array 320 feet wide. He later bought a 4 square system and put it up. He 
would ask questions regularly through e-mail and share how he and Coby were 
doing. It must have been over a year ago when the e-mails stopped. He was still 
talking then about wanting to work DX and moving his arrays around. He thought 
maybe just putting the 4-square up after the horses were moved as it was 
easier. He was doing all this in his late 80's and early 90's.  I think it was 
about a year ago when he said it was getting harder to figure the arrays out 
anymore as he had a printed out stack of e-mails from me that was 2 inches 
thick.
  A funny story about his first Hi-Z RX array he put up with my 
electronics. He worked his tail off putting up the verticals and stringing the 
cables etc. He finally settled down to try it out. He thought it was not 
working as good as his phased verticals and Beverages for top-band. He spent 
hours and days checking everything out. Then one day much later after 160 was 
wide open and he worked many many stations with his Beverage really bringing in 
the stations better than any other antenna, he e-mailed and said to me he owed 
me an apology, he said he had miswired his home made antenna switch and he had 
really been using the BSEF array and it was in fact outplaying any of his other 
RX antennas. He was pretty excited that all the work had paid off. We got a 
good laugh out of that.
Before I got overloaded commercially making Hi-Z a business I started 
writing a book about high impedance technology with antennas. I sent him a 
draft and he was kind enough to look it over with suggestions for improvement. 
He obviously spent many hours looking at my drafts making school teacher type 
notes.  Not many knew it but he also managed a mountain top repeater site 
commercially as well.
   He is a great guy when you get to really know him. It would be awesome to 
contact him again.
   Thanks Tree.
Lee   K7TJR   OR

-Original Message-
From: Topband  On Behalf Of Tree
Sent: Saturday, December 1, 2018 8:01 AM 
To: 160 
Subject: Topband: W7LR

Many of you have probably noticed that W7LR has not been in the pileups during 
the past year.  I visited Bob exactly a year ago and Cobi as well - Cobi had 
reached 100 years.  Bob is close behind.

Cobi passed away on April 1st and Bob has moved into an assisted living 
facility around the same time.  His station is QRT.  I chatted with him 
yesterday and it was good to hear his voice.

If anyone is interested in sending Bob a note - I can provide the address.

Tree N6TR
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Topband: 4sq vs SAL 30 Mkii in a forest

[Lee STRAHAN]

   Since the inception of the Hi-Z antenna products we have recommended that 
the elements be distant from foliage by at least 5 feet clearance. We have also 
recommended that tall trees be 10 feet away from the elements. We have had 
customers install arrays literally among forests without their reporting 
adverse effects on the array performance. With this one exception. A high 
impedance array was installed on a small lot in Florida where after a month or 
two of scientific experiments it was decided that close Palm tree fronds were 
affecting this array installed around a house. The experiments revealed a very 
high dielectric property which may be part of the answer to the effect. They 
were trimmed back lessening the effect. After many years I recall no instance 
where the arrays have reportedly been affected by other types of trees near the 
elements. I have no knowledge of the SAL-30 except for meeting KB7GF the 
designer at Dayton and comparatively running the NEC model he published.

Lee   K7TJR
Hi-Z Antennas




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Re: Topband: 4sq vs SAL 30 Mkii in a forest

[Lee STRAHAN]

   Joe and all,
  Looking at the YCCC plots show all back lobes on 160 meters to be right at 20 
dB down. The Hi-Z 4-square as shipped has only 2 side lobes and both are at 20 
dB down with a notch directly off the back at usual 30+ dB down. Its true there 
are plots around that show the -13 dB side lobes on the 4-square which is a 
special phase delay to maximize the RDF another 0.1 dB or so.
   In addition, the 4-square suffers NO degradation in pattern and produces the 
same F/B and RDF on 80 meters as it does on 160. The YCCC is degraded on 80m. 
If the 4-square is built on a 60 foot side dimension instead of the usual 80 
feet there is less than 1/10 reduction in RDF on 160 and the nearly same 160 
meter performance is also available on 40 meters as well.
There is one fact that remains. Having any receiving antenna that works is 
always better than none at all. Compromised or not. The only indicator of 
performance in the long run is smiles behind the dial. Hope you, K7XH get lots 
of private messages to help you with your choice as well. I am thinking your 
trees are a non-issue.

Lee   K7TJR
Hi-Z Antennas


 


 > Any experience with the same or  thoughts?

I would recommend looking into the YCCC "9 circle" (or "5 square") array.  Even 
though the kits are no longer available boards appear to be available from the 
PI4CC group.

The vertical arrays are less susceptible to wildlife damage than the SAL (due 
to the low horizontal wire of the SAL) and provide a higher signal level 
(before the preamp).

I like the YCCC design because it has a cleaner pattern than the
4 square (the center element is not "split" and thus does not cause a spurious 
sidelobe response).  Further, the "9 circle"
version provides 45 degree pattern selection (vs. 90 degrees for the 4 square) 
and if 90 degree steps are acceptable, the 5 square version provides the higher 
RDF in the same space (60' diagonal square).

As long as you keep the verticals (or the ends of the SAL) 10 - 15'
or so from tree trunks and keep the "brush' out of the array any degradation 
should be minimal (mostly as additional losses) with any of the antenna designs.

If you are comfortable with NEC (antenna modelling), I urge you to run the 
models of all three designs and make your own choice.  Based on the models, the 
SAL appear to be "unstable" and more prone to environmental factors that the 
"amplified" vertical arrays.

73,

... Joe, W4TV


On 2019-02-18 2:56 PM, Mike Fischer wrote:
> Hi all, newb to the topband 160 reflector here so thank you for any 
> coaching or corrections on protocol…
> 
> I live on a heavily forested (douglas firs - almost all of which are 100’+) 
> piece of land.
> 
> I have enough room left to put up either an SAL 30 or a  4sq of 20’ 
> verts with 80’ spacing. HiZ probably
> 
> Problem is regardless of which I choose, there will be at least one or two 
> trees in the “infield“ and foliage around the edges.
> 
> Any experience with the same or  thoughts? Grateful for the coaching 
> please feel free to reply direct to  mikebfisc...@comcast.net
> 
> 73
> K7XH
> 


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Re: Topband: RX and TX remote direction switch

[Lee STRAHAN]

  I used to use rotary switches also but once I developed the coax switches for 
Hi-Z that have 80 dB of cross port isolation. I would never go back to using a 
switch or single relay with a typical cross channel isolation from their on/off 
ratio being only 40 dB or so. This is especially important when you are using 
receiving antennas with very high RDF and front to side/back ratio.
 Lee  K7TJR   OR



> This is used to replace a traditional manual rotary or push button 
> direction switch.  Although a system something like this is required to 
> control antennas at a remote QTH, it can be useful at 73, de steve ve6wz.
> _

I used to have 6  Beverages at 60 degree Azimuth intervals.
I originally used a rotary switch, then I went to a system like VE6WZ.  Once I 
used it, I would never consider a rotary switch.

Rick N6RK
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Re: Topband: Thanks

[Lee STRAHAN]

Rich K7ZV was reporting he was hearing Dave very light from his hilltop place 
in southern OR. He was unable to make the Q. I have a pretty high noise floor 
at the moment and did not hear anything except a ping or 2 at some 200 miles 
North of Rich.
Sigh,
Lee   K7TJR  OR

-Original Message-
From: Topband  On Behalf Of w...@w5zn.org
Sent: Sunday, February 24, 2019 12:26 PM
To: Tree 
Cc: 160 ; Raymond Benny 
Subject: Re: Topband: Thanks

The propagation into Arkansas on 160 meters from 4U1ITU is pretty much a black 
hole. I can only imagine what is like further west

Joel W5ZN


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Topband: V84SAA 2019

[Lee STRAHAN]

Every once in a while we on the West coast of the US see a little advantage 
for our DXing efforts over the East coast operators. V84SAA with their awesome 
expertise has shown to be one of those times. Kudos to the boys for some great 
DXpedition work. Their signals on the west coast 7600 miles away were simply 
outstanding. Particularly on 160 meters which interests me the most. I have 
placed some recordings on the cloud of what I was able to hear from here. These 
recordings were made on an experimental 3 element Hi-Z array. The recording 
file name with no band notation is from 160 meters. During that recording I 
switched from my transmitting antenna to the 3 element array. You can tell the 
switch point from the background noise increase. Their signal was quite good 
here and I would have been able to make the contact using only my TX antenna.
  Also kudos to Jeff for untiring dedication.
Here is the link to the recordings.  
https://1drv.ms/f/s!Aic-1tUvn-65gWcEGD2tNa-JITWd

Awesome.

Lee Strahan
K7TJR

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Re: Topband: Counterpoise

[Lee STRAHAN]

   Hey Bob,
Don’t forget that you could interfere with your Hi-Z receiving array by 
getting more radials close to it.
LeeK7TJR   OR

-Original Message-
From: Topband  On Behalf Of Chortek, Robert L.
Sent: Tuesday, April 16, 2019 10:34 AM
To: topband@contesting.com
Subject: Topband: Counterpoise

Fellow Topband Aficionados -

Question about wire layout in a elevated counterpoise system. 

My top loaded vertical stands right next to the house on the far side of our 
tiny suburban lot. The radials slope upward from the base at 3’ feet to the 
roof at about 10 feet, make a 90° turn and then run over the top of the house 
creating a giant U shape.

I’m wondering whether adding additional radials would improve the performance 
of the system, given that those additional radials will have to run pretty 
close to the existing 12, none will run in a straight line. 

Thoughts? 

Thanks for your input Xcode

Sent from my iPhone
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Re: Topband: Hi Z 4 el. RX array LNA protection

[Lee STRAHAN]

   Hello Mark,
   Yes I do read most postings on this reflector. It is a great group.
I think there is likely over 1000 of the Hi-Z amps around the world. I have no 
direct knowledge of any amp damaged from locally transmitted RF with one 
exception. We tried it with a lot of power really close. One fellow in EU tried 
to make a combination Hi-Z array and 30 meter transmit array all in one 
footprint? Poof! Yes, the amps have unique circuit design internally to protect 
themselves. That is one of the reasons there is 4 to 5 Volts DC on the antenna 
elements during normal operation. There is also an internal relay that grounds 
the antenna through a 1/4 watt resistor when the power is removed. This is 
there for lightning protection where one turns the array power off when not in 
use. It is not necessary to remove power during your transmitting or normal 
use. Yes, we have had units come back or be repaired in the field that have 
that resistor burned out when the rest of the circuitry remained calibrated and 
fully operational. Cheap insurance.
   There is a 75 ohm post combining preamplifier that can also handle your TX 
voltages during transmit. The only caveat with it is you cannot short the 
output of the arrays during transmit as that preamp will try to put all that RF 
from your transmitter into a short circuit. It will blow the 2N3866 transistor 
used in that preamp.
   Lastly you should be aware that with your TX array this close to the RX 
array you will have interaction likely causing pattern distortion during RX. 
One way to deal with that is to detune the TX elements during RX. I suggest you 
contact Gary KD9SV about detuning towers. He also makes front end protectors 
always a good idea.

Lee   K7TJR
Hi-Z Antennas




Subject: Topband: Hi Z 4 el. RX array LNA protection

Don’t recall if the owner of Hi Z monitors this site. 

Question 

Is there any protection for the individual LNA’s for strong signals?  Am 
planning to add a RX protector where it connects to the RX antenna port and of 
course that that does not protect the LNA’s. 

As much as I would love to put the array many hundreds of feet from the TX 
antenna, it’s just not possible.  Please advise!  Thanks

Regards,

Mark, K1RX


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Re: Topband: RX antennas comparison chart

[Lee STRAHAN]

I have another comparison chart here on the Hi-Z Antennas website. It has a 
little more information.
https://www.hizantennas.com/receiving_antennacomparison_char.htm 

Lee  K7TJR
Hi-Z Antennas

-Original Message-
From: Topband  On Behalf Of terry burge
Sent: Tuesday, July 30, 2019 11:44 AM
To: topband@contesting.com; terry burge 
Subject: Topband: RX antennas comparison chart

Thanks to Bob, N4PQX I got this link to an active chart comparing RX antennas. 
Thanks to K7TJR this might prove very helpful to anyone thinking about 
investing in a receive antenna. Also has some active plots for the various 
antennas. Terry, KI7M


https://www.k7tjr.com/rx1comparison.htm


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Re: Topband: Which RX antenna is better?

[Lee STRAHAN]

Agreed Chuck, 
 I maybe read David's post differently than he meant it to read also.
   This progression from TX antennas to loops to Beverages to 8 circle arrays 
is exactly how Hi-Z began. It is because the 8 circle is head and shoulders 
above all other choices at this location that Hi-Z Antennas even exists. Many 
different antennas have been tried here as well including loops and long 
Beverages.  Many more comparisons have been made between different types that 
say under correct hardware application conditions and propagation conditions 
the best signal to noise reception for DX stations is with the 8 circles. All 
this says nothing about bang for the buck, real estate, or ease of installation 
which is a whole different way of looking at this. 
   Where low angle DX is concerned I have actually measured the signal to noise 
ratio of signals from different receiving antennas and indeed at my location 
the best signal to noise reception follows the best RDF antenna. It may be true 
that a SAL-30 is appealing for other reasons but there is no way it would ever 
produce as good a signal to noise ratio on 160 meter DX signals as a properly 
operating 8 circle. Active or passive either one. The SAL antenna makes a great 
contest antenna as it has a wider beam width which hears more contest stations 
than the very narrow 8 circle patterns. Some Hi-Z contest users actually use 
both antennas so when a  weak one comes along they switch to the 8 circle. 
   I suggest ones that have not seen them to view Frank  W3LPL's videos on 
receiving antennas. This is a very good presentation.

Part 1  https://www.youtube.com/watch?v=RX4eLmJWNeo   part 2  
https://www.youtube.com/watch?v=fyZR9uMBnIo 

Everyone's mileage may vary.

Lee   K7TJR
Hi-Z Antennas


-Original Message-
From: Topband  On Behalf Of Chuck Dietz
Sent: Thursday, August 1, 2019 10:40 AM
To: Rodman, David 
Cc: topband@contesting.com
Subject: Re: Topband: Which RX antenna is better?

Your results of the order of performance of these antennas are somewhat 
different than other, published results. I wonder if the composition of your 
ground would have something to do with that? Good or poor soil?  Also, how long 
was the Beverage?
I have a SAL-30, which is by far my best receive antenna since I had to take 
down my Beverages, but my take away was the Beverages beat the SAL-30 most of 
the time. This is over medium to good soil. I would have expected the 8 circle 
to be better than all the others at least 90% of the time. (At least over good 
soil.)

I have been pondering which receive array to put up in a new location with 
plenty of room, so I have been looking at this.

Chuck W5PR

On Thu, Aug 1, 2019 at 11:19 AM Rodman, David  wrote:

>
>
>
> This is possibly a more complicated subject than just performance.  I 
> gave a lecture on this topic, comparing a Hi-Z circle 8, SAL-20, 
> SAL-30, beverage (unidirectional and bidirectional and BOG) and the K9AY 
> array.
>
>
> In this talk, I considered performance as a factor, but also 
> considered maintenance, size, mechanical stability, cost and ease of 
> construction and installation.
>
>
> All things considered, the top 2 at my QTH were the Hi-Z circle 8 and 
> the SAL-30.
>
>
> Here is a quick summary of my findings.
>
>
> Circle 8: highest cost, most complex to install and construct, 
> requires large footprint of land, best of all antennas as it requires 
> almost NO maintenance and performance second overall to the SAL-30.
>
>
> SAL-30: modest cost, modest install and construct, modest footprint, 
> requires minimal repairs (usually to the coupler wires) but overall 
> performance best of all for directionality and gain.
>
>
> SAL-20: modest cost and somewhat simpler than SAL-30 to install and 
> small footprint.  Performance almost identical to the K9AY array.
>
>
> K9AY: modest cost but slightly more complex to construct as compared 
> to
> SAL-20 and about the same size.  Performance less than SAL-20 due to 
> fewer directions.
>
>
> Beverage unidirectional: mechanical stability good when constructed 
> with copper coated steel wire #14 or larger.  Gain fine when desiring 
> only 1 direction.  Depending on the location may be placed in half a 
> day from start to finish.
>
>
> Beverage bidirectional: mechanically unstable when constructed with 
> commercial products using either RG6 or twin lead.  Requires frequent 
> repairs due to fatigue or failed connections.  Performance overall is 
> not on par with other directional arrays.
>
>
> BOG: simplest of all antennas to construct, install and maintain.  Can 
> be installed in an hour or two.  Should be unfolded at spring time 
> each year to keep wire from being incorporated into lawn.  Convenient when 
> only 200'
> available.  Can be band specific.
>
>
>
> Just a quick summary.  My location does not lend itself to beverage 
> construction. about 2/3 of my 25 acres are heavily and complexly treed 
> with brush so overgrown that it can be 

Topband: 160 meter noise

[Lee STRAHAN]

  I have a Ray Jeff 680/ADF marine radio direction finder I have used for noise 
location for a long time and it is in need of some maintenance.
I have looked for a schematic for years without success. If anyone has a 
schematic they could share I would appreciate a copy.
Even a similar model number schematic may help.
Thanks Guys,

Lee   K7TJR   OR.

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Topband: YCCC 9 circle preamp failure test

[Lee STRAHAN]

Hi Guys,
  Assuming your verticals have a very good insulator there is NOTHING to stop 
that input capacitor from charging to very high like kilovolt static voltage 
levels. What I don’t understand is why leakage in that capacitor would cause 
any trouble or differences if it were not even there.  All that would happen is 
the vertical would assume about 5 volts DC on the elements. This problem 
rearing its head would indicate the vertical insulators or something in that 
path must be compromised as well. Or is the 8055 possibly going in to 
oscillation with a leaky connection to the element.
  Something does not add up here.??? What is the clue that tells you the 
capacitor has failed. Lack of performance/directivity or noise. Noise might 
indicate oscillation. 
Lee   K7TJR
Hi-Z Antennas



-Original Message-
From: Topband  On Behalf Of VE6WZ_Steve
Sent: Tuesday, September 24, 2019 11:09 AM
To: topband 
Subject: Topband: YCCC 9 circle preamp failure test

Yesterday I decided to measure the actual voltage at base of my short HI-Z 
verticals while I transmitted on the TX array.

Since I first posted about the coupling capacitor failures in these units, I 
have received private emails form 4 others with the same problem.

My question is what has caused these failures? Is it a lightning event,  is it 
high-potential wind static on the vertical elements or is it from TX RF 
overload.

TX overload seemed possible at my location because my array is less that 100’ 
from the TX antenna.  I built a diode detector probe and in the field measured 
the actual voltage when TX.  The results indicate at most I see 50 v at the 
pre-amp.  The coupling caps are 63v rated units.  This would indicate that RF 
overload is not the cause, but I would really like thoughts and opinions from 
others.
I have redesigned the amps to include a relay to short out the antenna when not 
powered up, so I feel I am protected from any cause.

Here is a link to a YouTube video that shows the test set-up and the actual 
measurements I made in the field.  I also talk about using gas discharge tubes 
as a remedy.

https://youtu.be/TmM_YnLob68 

73, de steve ve6wz

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Re: Topband: Shunt feed question

[Lee STRAHAN]

  Marty,
  You may be seeing errors in your readings due to broadcast pickup. This is 
common when modern R+Jx measurement tools are connected to large antenna 
structures. Others have described ways around this problem before here on the 
topband chat.
Lee  K7TJR  OR


Thanks for the response Herb. I can obtain a good match using the 65 ft tap 
point, but my question is why my analyzer is measuring a change in the 
feedpoint resistance (real component of R + jX). 

Regards,
Marty

> 
> Best to use a 3 or 4 wire cage feed and you will find the match easier.  You 
> should tap the tower at 50 feet and work down till you find the sweet spot.  
> A 500 to 750 vac variable will take care of any measure inductive component.
> 
> Herb, KV4FZ
> 
>> On Tue, Oct 15, 2019 at 3:10 PM Marty Ray  wrote:
>> I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA at 
>> 70 ft and a full size 40m rotatable dipole at 79 ft, (the top of the mast is 
>> ~85 ft). Both antennas have relays that electrically bond them to the tower 
>> when the shunt feed is in use. 
>> 
>> I have tried two shunt tap points, one at 65 feet and another at 45 feet. 
>> Using a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on the 
>> 65 foot version and 49 ohms on the 45 foot version. In both cases, adding 
>> the shunt capacitor caused Rs to drop by approximately 50 percent, (to 
>> around 60 ohms and 23 ohms respectively).
>> 
>> I expected Rs to not change much, if any. I tried a vacuum variable, an air 
>> variable and a silver mica. Same result. 
>> 
>> Has anyone seen this happen before?
>> 
>> Regards,
>> Marty N9SE

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Topband: Hardening the 8 Circle Receiving Array

[Lee STRAHAN]

   Hi Folks,
The Hi-Z Antennas brand amps already have a path to drain static as they 
are designed to produce 4 to 5  Volts DC on the element with an internal 
voltage divider. Attaching another resistor would degrade the performance.
Not only does this protect from static but it is a great first step diagnostic 
tool when checking the health of the system. The YCCC systems are capacitively 
coupled and could benefit from a 1 Megohm resistor across their amp terminals 
to drain static. There have been quite a few recent reports of this input 
capacitor's failure. Albeit no one has determined the exact cause of the 
failure yet to my knowledge.

Lee   K7TJR
Hi-Z Antennas




Hello Mark!

I have the YCCC Hi-Z spaced at the compromised 60 ft. parameters to improve
80 & 40m operation - that was a mistake!  
Go with the recommended 160m spacing.  I plan to modify my Hi-Z for optimum 
160m operation ASAP.

Since the Hi-Z sits on the ground, putting it out in the fall and bringing it 
back in every spring is not a big deal.  It only takes a couple of hours.
Lightning protection is not usually an issue in the colder months, although we 
do get "Thunder-Snow" occasionally, but so far no damage from that.

For static build-up protection, which is a real problem in the winter months, I 
installed 100K 1w carbon resistors bridging the inputs to ground.

This will be the 4th or 5th year for my Hi-Z array.  I also have BOGs and two 
types of RX loop antennas.  

Lloyd - N9LB


GM Mark,
The easiest way to think of this is Diodes = Detectors; with high-powered RF 
around, that becomes a Bad Idea. A possible alternative MAY be high-value 
resistors to ground across the front end of the preamps. A representative value 
would be 10 MΩ or greater, and I would match the resistances to ±1%.
However, Tim's warning still applies in that this mod may damage the 
performance of the array. I only mention it because I've used it with kite and 
balloon antennas to drain off static discharge, and it may prove useful here. 

73 de Lee KX4TT




Hello Mark:

Installing diodes can cause severe problems with nearby broadcast stations.

During the summer months and lightning months I remove my preamps from the 
antenna elements to protect them. 
I am now just getting them installed tomorrow morning to prepare for the Fall 
Stew contest on Saturday.

Be careful making modifications that may hurt your array performance

73
Tim K3LR


I  have the DX Engineering 8 circle receiving array sized for 80/160m . 
It has been a fantastic performer but I have suffered damage to the active 
antenna amplifiers on two separate occasions due to nearby lightning strikes.

I am looking at a way to protect these amplifiers.  I was wondering if I can 
add a pair or  dual series pair (4 diodes in total) of back to back diodes - 
say 1N3600,  across the input to ground terminals on each amplifier.  Will this 
affect the performance of the array in any way ?

73 Mark N1UK

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Re: Topband: YCCC 9 circle preamp failure test

[Lee STRAHAN]

Hello again Steve,
   It seems to me that one could determine what was going on by making two 
tests. One is to simply bypass the capacitor with a wire to see if its 
rectifying. The other is to monitor the DC voltage on the output pin of the 
8055. If for some reason there is leakage causing the problem the voltage at 
the output pin of the 8055 would be something different than ~1/2 the value of 
the 4740A Zener voltage. About 5 VDC.
  Of course all this capacitor damage would maybe not happen with a drain 
resistor of 1Megohm or so right on the input terminals. But why do that if you 
can successfully short that input capacitor and not use at it at all putting a 
few volts on the element. A regular old discap would be a good choice for a 
replacement if one wanted higher voltage capacitor. 
 I highly recommend that the element insulators be checked for leakage also.  
They should be around a Megohm or more with nothing connected.  

Lee   K7TJR
Hi-Z Antennas


-Original Message-
From: VE6WZ_Steve  
Sent: Tuesday, September 24, 2019 1:58 PM
To: Lee STRAHAN 
Cc: topband 
Subject: Re: YCCC 9 circle preamp failure test

Hi Lee…

You are absolutely right, a failed coupling cap should not change the basic amp 
performance. All that we will get is some of the op-amp voltage leaking onto 
the element.

However, my initial indication that something was wrong was in the east 
direction I had what sounded like BC inter-mod rectification products.  Most of 
the noise, crud and carriers were centred around 1820 kHz.  On the waterfall it 
was really obvious.  Its that typical BC junk that shows up with a poor 
connection somewhere. I was sure it was a poor connection somewhere on the 
vertical or at the connections.  After I found nothing, I switched the amp out 
with a spare I had and the noise junk was gone.
I was sure it was a bad Op-Amp.  I switched it out, but also noticed that the 
coupling cap was leaky, so I switched that out too.  Amp was restored.

A few weeks later, the same noise showed up again, but this time in all 
directions.  In this case I realized it was the central vertical. I tested the 
cap, and it was leaky so I replaced it, and the amp tested good with the 
original op-amp.  Later on, I tested all the pre-amps and found a third bad 
cap. However, in this case the pre-amp was still performing ok with no noise, 
so as you suggest, not in all cases do the failed coupling caps cause a problem.

The “bad” caps do not fail completely short, but are leaky…around 20k-50k ohms. 
 Is it possible that the dielectric is compromised enough that we are getting 
some diode rectification action that is generating the crap?

Either way, whatever the failure cause, it could be putting stress on the 
op-amps which could cause them to fail eventually too.

Steve


> On Sep 24, 2019, at 1:08 PM, Lee STRAHAN  wrote:
> 
> Hi Guys,
>  Assuming your verticals have a very good insulator there is NOTHING to stop 
> that input capacitor from charging to very high like kilovolt static voltage 
> levels. What I don’t understand is why leakage in that capacitor would cause 
> any trouble or differences if it were not even there.  All that would happen 
> is the vertical would assume about 5 volts DC on the elements. This problem 
> rearing its head would indicate the vertical insulators or something in that 
> path must be compromised as well. Or is the 8055 possibly going in to 
> oscillation with a leaky connection to the element.
>  Something does not add up here.??? What is the clue that tells you the 
> capacitor has failed. Lack of performance/directivity or noise. Noise might 
> indicate oscillation. 
> Lee   K7TJR
> Hi-Z Antennas
> 
> 
> 
> -Original Message-
> From: Topband  On Behalf Of VE6WZ_Steve
> Sent: Tuesday, September 24, 2019 11:09 AM
> To: topband 
> Subject: Topband: YCCC 9 circle preamp failure test
> 
> Yesterday I decided to measure the actual voltage at base of my short HI-Z 
> verticals while I transmitted on the TX array.
> 
> Since I first posted about the coupling capacitor failures in these units, I 
> have received private emails form 4 others with the same problem.
> 
> My question is what has caused these failures? Is it a lightning event,  is 
> it high-potential wind static on the vertical elements or is it from TX RF 
> overload.
> 
> TX overload seemed possible at my location because my array is less that 100’ 
> from the TX antenna.  I built a diode detector probe and in the field 
> measured the actual voltage when TX.  The results indicate at most I see 50 v 
> at the pre-amp.  The coupling caps are 63v rated units.  This would indicate 
> that RF overload is not the cause, but I would really like thoughts and 
> opinions from others.
> I have redesigned the amps to include a relay to short out the antenna when 
> not powered up, so I feel 

Re: Topband: 9 circle RX array combiner board

[Lee STRAHAN]

  Hi Guys,
   I got advance information of the 2N5109 and its cousin the 2N3866 
transistors demise.  I used the 2N3866 in my older design Hi-Z 75 ohm preamp so 
this transistor should suffice in most preamps that used the the 2N5109 . I 
bought a good supply of the 2N3866 devices and can offer them up to the ham 
community for $3.00 each in small quantities. I intend to support hams that are 
in need of these devices in small quantities only which should prolong the 
lives of the ubiquitous single transistor feedback preamp such as the HI-Z and 
the W7IUV.
   I am not selling these transistors through Hi-Z Antennas but through private 
sales. E-Mail through k7...@msn.com or address below. There is no profit to me 
involved. There will be postage costs involved also.

  Also do not buy the Motorola labeled 2N3866 or 2N5109 devices from China 
as they are nothing more than audio transistors at best. I tried them.

LeeK7TJR
8125 SW Larch Dr.
Culver, OR   97734



-Original Message-
From: Topband  On Behalf Of 
Richard (Rick) Karlquist
Sent: Sunday, March 1, 2020 3:31 PM
To: VE6WZ_Steve ; Topband 
Subject: Re: Topband: 9 circle RX array combiner board



On 3/1/2020 2:22 PM, VE6WZ_Steve wrote:
> Just like some guys enjoy woodworking and making furniture that they may not 
> really need, I like to build radio things just for the fun of the project 
> even though I may not really “need” it.  For three years I have been using 
> the original 9 circle RX array kit that I bought from DX-engineering, and it 
> has performed well, but I wanted to build my own and add my own design tweaks.
> 
> Using KiCad, I have designed and built a 9 circle RX array combiner with a 
> 2N5109 pre-amplifier integrated onto the same board.
> 

> 73, de steve ve6wz
> _
>

Now I know why you work stuff I can't even hear :-)

The 2N5109 is just about extinct.  Did you secure a source for it before you 
laid out your PC board?  If you did, please share it with the rest of us.  Most 
people are now using substitutes for the 2N5109 with varying degrees of 
success.  Are you possibly doing that?  Of course those substitutes are not in 
a hermetic metal can, so the PC board has to be laid out for differently for 
them.

You might want to look at these references for so-called "E-field" arrays of 
whip antennas:

A military design:

https://www.dst.defence.gov.au/sites/default/files/publications/documents/DST-Group-TR-3522.pdf

Various improvements to the above:

http://home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf

You also find a lot of other good stuff on Chris's site.

They go beyond the DXE design.

Good luck with your project.

BTW, how do you like KICAD?  I'm currently using a grandfathered EAGLE 7.7 
perpetual license, but "some day" I might switch to KICAD.

73
Rick N6RK
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Topband: YCCC 9 Vertical Array Preamplifiers

[Lee STRAHAN]

There seems to be some confusion about. 
 Let me explain the significance of Joel's comment about the high impedance 
amplifiers. I have developed new versions of the Hi-Z amplifiers I use in the 
Hi-Z array products. Joel W5ZN was given a set of these Hi-Z amps as a Beta 
test in the field for my new design. The whole purpose of one version (-6dB 
version) was to replace any of the really old amplifiers sold with the early 
arrays and to retrofit directly into the YCCC arrays. The new design has 
several advantages including Low Noise, more gain/phase accuracy, lower cost, 
and higher IMD specs compared to our older amps.
   8 of these amps were also given to Eric NO3M for a beta test in his 630 
meter 8 circle receiving array to replace the YCCC designed amps. I am happy to 
say they participated in his recent record 630 meter contact to VK4. 
   There is also another version called the Plus V2 version that has 6 dB more 
gain and will replace the current version in most new arrays and production as 
time goes on.
 The amps have been submitted to DX Engineering and will show up in their 
offerings soon. 
   Sorry for the shameless plug but some information was needed.
Lee   K7TJR  OR

-Original Message-
From: Topband  On Behalf Of 
w...@w5zn.org
Sent: Sunday, March 1, 2020 9:52 PM
To: topband 
Subject: Re: Topband: YCCC 9 Vertical Array Preamplifiers

Allow me to clarify my post. I was referring to the high impedance amplifiers 
at the vertical elements, not the 2N5109 preamp used sometimes post combiner.

73 Joel W5ZN


On 2020-03-01 20:27, w...@w5zn.org wrote:
> As an alternative to the 2N5109 preamps, last year I acquired a set of 
> HiZ preamps to use on my YCCC 9 Circle array elements. They work 
> exceptionally well and exhibit a lower noise figure that I experienced 
> with the original YCCC amps.
> 
> I mentioned this solely for information with no other purpose as I 
> realize some like to use a simpler amplifier design that they can 
> build and/or repair. If you have an interest other than what has been 
> mentioned you can contact Lee at HiZ.
> 
> 73 Joel W5ZN
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Topband: YCCC 9 Vertical Array Preamplifiers

[Lee STRAHAN]

  Hello Henk and others,
 I can surely see your point about how interesting that would be to share 
all the circuit details. However you would have to understand that what you 
propose is exactly what I did many years ago. I published on the web my entire 
design and processes I used to make the original 8 element all active array. It 
indeed was a very interesting topic for discussion. It brought many requests 
for more information. Then came the requests can you make one for me? I have 
never forgotten those words but I have forgotten who asked them.
 I did not start out with the idea I would make and sell anything to anybody I 
just wanted to share with the world what I had done. As word got around I no 
longer had a choice in the matter if I would make some or not. I made some Hi-Z 
amp kits.  First it was those Hi-Z amps are nice can you make a smaller array 
for us so we can use those amps. Well, that was the simple part after I had 
engineered over 4 years making the all active very complex 8 element array, 
making smaller arrays was very easy. The questions were non stop. A few had 
attempted home built arrays and the questions still came and then  I realized I 
cannot support what other people had done with my designs. There is so much 
more than meets the eye in a complex array like these. For an example, very few 
people realize that even a simple 10 turn transformer can have up to several 
degrees of phase shift at 160 meters just due to the wire length alone. Double 
that at 80 meters and even more at 40 meters etc.. I could not s
 upport 10 different people whom had wired transformers 10 different ways. That 
is just one minute thing about these designs. I realized that if I was going to 
support these arrays I would have to control the designs in order to keep my 
sanity. So I removed all the circuit details from the original web page and 
have kept the details mostly under wraps. I still share some service 
information as needed and even these sometimes are very difficult to 
troubleshoot over long distances. The very reason that the Hi-Z arrays 
outperform most receiving antennas is because of the attention to detail in the 
circuit design and attempting to build these in a home lab is very difficult at 
best.
   So Henk, the bottom line is I tried what you suggest and it was not 
possible. Under these circumstances I feel I am providing the very best I can 
for the top-band community.

Lee   K7TJR
Hi-Z Antennas



-Original Message-
From: Topband  On Behalf Of Henk 
Remijn PA5KT via Topband
Sent: Wednesday, March 4, 2020 12:14 AM
To: topband@contesting.com
Subject: Re: Topband: YCCC 9 Vertical Array Preamplifiers

I think it is more interesting for the Topband community that you publish your 
design and let the people build their own.

73 Henk PA5KT

Op 4-3-2020 om 01:31 schreef Lee STRAHAN:
>  There seems to be some confusion about.
>   Let me explain the significance of Joel's comment about the high impedance 
> amplifiers. I have developed new versions of the Hi-Z amplifiers I use in the 
> Hi-Z array products. Joel W5ZN was given a set of these Hi-Z amps as a Beta 
> test in the field for my new design. The whole purpose of one version (-6dB 
> version) was to replace any of the really old amplifiers sold with the early 
> arrays and to retrofit directly into the YCCC arrays. The new design has 
> several advantages including Low Noise, more gain/phase accuracy, lower cost, 
> and higher IMD specs compared to our older amps.
> 8 of these amps were also given to Eric NO3M for a beta test in his 630 
> meter 8 circle receiving array to replace the YCCC designed amps. I am happy 
> to say they participated in his recent record 630 meter contact to VK4.
> There is also another version called the Plus V2 version that has 6 dB 
> more gain and will replace the current version in most new arrays and 
> production as time goes on.
>   The amps have been submitted to DX Engineering and will show up in their 
> offerings soon.
> Sorry for the shameless plug but some information was needed.
> Lee   K7TJR  OR
>
> -Original Message-
> From: Topband  On Behalf 
> Of w...@w5zn.org
> Sent: Sunday, March 1, 2020 9:52 PM
> To: topband 
> Subject: Re: Topband: YCCC 9 Vertical Array Preamplifiers
>
> Allow me to clarify my post. I was referring to the high impedance amplifiers 
> at the vertical elements, not the 2N5109 preamp used sometimes post combiner.
>
> 73 Joel W5ZN
>
>
> On 2020-03-01 20:27, w...@w5zn.org wrote:
>> As an alternative to the 2N5109 preamps, last year I acquired a set 
>> of HiZ preamps to use on my YCCC 9 Circle array elements. They work 
>> exceptionally well and exhibit a lower noise figure that I 
>> experienced with the original YCCC amps.
>>
>> I mentioned this solely for information with no other purp

Topband: Topband resource

[Lee STRAHAN]

   And from the Northwest I have a slightly different observation of 
horizontal/vertical questions. What I have noticed is this. I more or less 
equate Horizontal antennas with high angle and vertical with low. The EU 
stations are usually mostly looking West into the setting sun. The East coast 
stations are looking into the total darkness toward EU mostly. Here in the 
Northwest we look into darkness toward EU and the East coast. I mention this 
because observations of high angle signals are VERY rare looking East toward 
EU. Maybe twice in 10 years. However looking West toward the setting sun and JA 
and UA0 I often see signals start early on the low angle vertical antennas and 
progress toward high angle signals in a same setting. The low horizontal takes 
over as the signals apparently get to a higher angle. I am about 200 miles from 
the Pacific. I have on my project list (way way down it) to build a high angle, 
low elevation horizontal array with a high RDF and gain just to see what it 
would do. Unfortunately it stays way down the list.
   For me Frank LPL says it all " You can never have too many antennas... 
Unless they interfere with each other, a non-trivial issue."
Lee   K7TJR   OR


It's more than antennas. There's also propagation. You're 700 miles ESE of me, 
which gives you a path to EU over less of the auroral zone.

AND there's noise, which has been increasing over time. My first years in W6 
were more productive for CW on Topband than now -- I have a dozen or so 
countries in the log from the solar minimum of those earlier years.

73, Jim K9YC

On 1/15/2020 6:21 AM, Wes wrote:
> Roger is in my logbook, along with at least five other "G" stations.  
> My station is described on my QRZ page.  I receive on the TX antenna.
> 
> Wes  N7WS

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Re: Topband: Topband resource

[Lee STRAHAN]

Yes, somewhat common in the "hollow state" device days(Tubes).
Old also Wayne.
Lee  K7TJR

Subject: Re: Topband: Topband resource

Very good Jeff! See Google/Wikipedia.  Wiki says "on the order of 1 pf/inch." 
(You must be as old as I am . . .)

- N7NG

On 1/14/2020 11:49 AM, Jeff Kincaid wrote:
> Hi Fred,
> Generally, a gimmick cap is two wires twisted together.  Your mileage 
> will certainly vary, but I seem to recall a rule of thumb suggesting 1 
> pF per inch.
> Regards,Jeff W6JK
>
> On Tuesday, January 14, 2020, 10:27:06 AM PST, fmoeves 
>  wrote:
> Mike, 160m antennas my favorite subject. I sure wish it would either 
> get cold or dry out here... Winters here in Kentucky are so wet and I 
> think it gets wetter every year. One thing I did read in that link was 
> reference to a "gimmick cap"...not sure what that is?? 73 Fred KB4QZH 
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Re: Topband: Hi Z amplifiers for 160m

[Lee STRAHAN]

   Hello John and all,
   Concerning the adding the noise in a typical array. If the noise was 
coherent or exactly the same signal from each element/amp the summed noise 
would indeed be 8 times. However circuit noise is always random and incoherent 
which causes the summation to be a single noise power times the square root of 
the number of elements assuming equal levels from each amp. In the case of 8 
elements 4.5 dB increase which is no small matter as well. In the case of the 
three elements the noise summation would be about 2.4 dB higher than a single 
element.
Lee  K7TJR  OR

As the designer of the YCCC high impedance feedpoint amplifier, let me address 
some issues related to the design of the YCCC amplifier as well as feedpoint 
amplifiers in general.  If you don't want to read a lot of technical 
gobbledygook, please disregard this message.

The YCCC uses an AD8055 RF amp as the gain element.  As Lee, K7TJF, points out, 
there are most certainly better op amps out there.  However, the AD8055 was the 
"best" part I could find in a DIP-8 package.  The "better" op amps are all SMT 
parts but given that the YCCC preamp was a kit, I intentionally limited the 
selection to DIP-8 parts that kit builders could work with relatively easily on 
a PCB.  Not everyone is able to do a competent job soldering tiny SMT parts.

Within the universe of available RF op amps, tradeoffs must be made in terms of 
noise, linearity, and bandwidth.  The AD8055 is not the lowest noise part but 
it has excellent linearity and plenty of bandwidth for HF use.  At my QTH there 
is an AM BCB station 3 miles away, which makes it a somewhat challenging EMI 
environment.  The decision to run the op amp in a unity gain configuration 
comes down to linear dynamic range.  It is easy to design for more gain, but it 
is also easily demonstrated that you will begin to suffer in terms of unwanted 
intermods.  With the YCCC preamp, I get absolutely zero BCB intermods or 
distortion products in the 160m band at my QTH.

In general I do not like to use an outboard preamplifier between the output of 
the phased array combiner circuit and my receiver because it degrades the 
linear dynamic range of the system.  The YCCC system user's manual (Section
12.1) does specify several outboard preamps that could be used.  In a low EMI 
environment, I think they all work fine.  However, at my QTH, with the nearby 
AM BCB station, all of them, without exception, generate increased distortion 
and intermod, which I find unacceptable.  

It is always desirable to apply RF gain with a roofing filter in front, which 
is becoming common practice in high performance receivers.  With my K3S 
receiver, the use of a unity gain antenna feedpoint preamplifier is perfectly 
fine if you also turn on the preamp in the K3S.  This gives the best overall 
linear dynamic range with a preamplified short vertical system.
There is no loss in noise performance because the noise on 160 and 80 is 
totally dominated by atmospheric noise.  In measurements I made at my QTH, the 
internal noise of the YCCC preamp is about 10 dB lower than my daytime 
atmospheric noise on 160m when using a vertical about 20 feet high.

You must also consider the number of active elements in an amplified antenna 
array when evaluating overall system noise performance.  This is because the 
amplifier circuit noise power of all the feedpoint amplifiers is added together 
when the elements are phased up in a combiner.  If you have N elements in your 
array, the effective circuit noise contribution gets multiplied by N.  The YCCC 
array has 3 active elements at a time.  However, the YCCC design is somewhat 
unusual in that maximum RDF is achieved when the signals from the elements are 
combined in unequal ratios.  As a result the effective amplifier circuit noise 
contribution is less than 3 times (or 4.8
dB) the noise of a single amplifier.  In fact because of the unequal combining 
ratios, the actual effective noise goes up by a bit less than 2 dB compared to 
a single amplifier.  An array like the Hi-Z array with 8 active elements 
combines the elements in equal proportion so the effective amplifier circuit 
noise of the system is 8 times (or 9 dB) higher than the noise of a single 
amplifier.  For this reason, the YCCC array can tolerate noisier amplifiers 
without degrading system noise performance.  The objective is to keep circuit 
noise well under atmospheric noise.

On the subject of op amp noise specs, you must consider *both* input voltage 
noise and input current noise because, in general, both contribute to the total 
output amplifier noise.  It is not good enough to pick an op amp with low input 
voltage noise without also considering the input current noise.
For a good noise analysis, download a copy of the datasheet for the CLC425 op 
amp:  http://www.elektronikjk.pl/elementy_czynne/IC/CLC425.pdf.  Refer to pages 
8-10.  (The CLC425 is a very good RF op amp but has been obsoleted by 

Re: Topband: Hi Z amplifiers for 160m

[Lee STRAHAN]

   Mike and all,
  Well stated Mike. It's been a long time since we have conversed. The 
modifier to this is when the signals coming into the combiner are no longer in 
phase or coherent. This as a result of delay lines and time of signal arrival 
at the many elements. Most often in our small portion of a wavelength low 
frequency arrays the combination of signals is subtractive to form a given 
pattern per array dimension. This then lowers the signal to noise ratio. It 
gets pretty complicated to arrive at a noise figure. The only way we have been 
able to do this with amplified arrays is to simulate the array in NEC being 
excited with a known signal many wavelengths away. We can extract the actual 
amplitude and phase of these multi element array signals and then combine them 
mathematically as you have done by example to arrive at a signal gain number 
from signal combination. The noise gain is easy. I say we because I have a 
retired very smart Ham friend in Finland that has helped me through this. It h
 as caused me to rethink gain distribution in some of my arrays.
Lee   K7TJR  OR

What matters is the signal-to-noise ratio (SNR). Take the canonical example of 
an ideal 2-port Wilkinson power combiner with in-phase coherent signals of 10 
Vrms applied to each input along with 1 Vrms random thermal noise from the 
respective element amplifiers applied to each input (i.e. each input signal has 
a 20*log(10 Vrms/1 Vrms) = 20dB SNR).

The power loss of the combiner is 3.01 dB [i.e. 10*log(2)], so voltage of each 
signal is attenuated by 1/sqrt(2) = 0.707. Thus, the components of each input 
signal appearing at the output are 7.07 Vrms each and
0.707 for each of the noise inputs.

The signal components add coherently at the combiner output yielding a total 
signal voltage of 14.14 Volts rms. The noise voltages are incoherent, so they 
add as root-sum-square at the output of the combiner. This yields a total noise 
voltage of sqrt(0.707^2 + 0.707^2) =
sqrt(1) = 1.0 Vrms. Thus, the combined noise voltage is unchanged, but the 
signal voltage goes up by sqrt(2).

The SNR of the combined output = 20*log(14.14Vrms/1Vrms) = 23dB, a 3dB 
improvement.

The same things holds for an ideal N-way combiner with equals noise components 
at each input. The noise power at the combined output equals the noise power of 
any of the equal input components (i.e. 0dB gain).

73, Mike W4EF..



On 3/11/2020 7:22 PM, Lee STRAHAN wrote:
> Hello John and all,
> Concerning the adding the noise in a typical array. If the noise was 
> coherent or exactly the same signal from each element/amp the summed noise 
> would indeed be 8 times. However circuit noise is always random and 
> incoherent which causes the summation to be a single noise power times the 
> square root of the number of elements assuming equal levels from each amp. In 
> the case of 8 elements 4.5 dB increase which is no small matter as well. In 
> the case of the three elements the noise summation would be about 2.4 dB 
> higher than a single element.
> Lee  K7TJR  OR
>
> As the designer of the YCCC high impedance feedpoint amplifier, let me 
> address some issues related to the design of the YCCC amplifier as well as 
> feedpoint amplifiers in general.  If you don't want to read a lot of 
> technical gobbledygook, please disregard this message.
>
> The YCCC uses an AD8055 RF amp as the gain element.  As Lee, K7TJF, points 
> out, there are most certainly better op amps out there.  However, the AD8055 
> was the "best" part I could find in a DIP-8 package.  The "better" op amps 
> are all SMT parts but given that the YCCC preamp was a kit, I intentionally 
> limited the selection to DIP-8 parts that kit builders could work with 
> relatively easily on a PCB.  Not everyone is able to do a competent job 
> soldering tiny SMT parts.
>
> Within the universe of available RF op amps, tradeoffs must be made in terms 
> of noise, linearity, and bandwidth.  The AD8055 is not the lowest noise part 
> but it has excellent linearity and plenty of bandwidth for HF use.  At my QTH 
> there is an AM BCB station 3 miles away, which makes it a somewhat 
> challenging EMI environment.  The decision to run the op amp in a unity gain 
> configuration comes down to linear dynamic range.  It is easy to design for 
> more gain, but it is also easily demonstrated that you will begin to suffer 
> in terms of unwanted intermods.  With the YCCC preamp, I get absolutely zero 
> BCB intermods or distortion products in the 160m band at my QTH.
>
> In general I do not like to use an outboard preamplifier between the 
> output of the phased array combiner circuit and my receiver because it 
> degrades the linear dynamic range of the system.  The YCCC system 
> user's manual (Section
> 12.1) does specify several outboard preamps 

Re: Topband: Hi Z amplifiers for 160m

[Lee STRAHAN]

John,
   Yes of course you are quite correct. I stand corrected.  I should not have 
used the word power. My thinking was along the line of what Mike W4EF posted.
Just did not say it right. Also, I have never disagreed with your choice of the 
8055 as I was aware of why you made that decision. Fortunately for us there are 
some op-amps now that show some really great specs. Unfortunately for us a lot 
of the older through the hole mount parts are disappearing quickly. Surface 
mount seems here to stay.
Lee  K7TJR

From: John Kaufmann 
Sent: Thursday, March 12, 2020 4:14 AM
To: k7...@msn.com; topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m

Lee,

I think you are confusing voltage and power.  For incoherent sources like 
amplifier noise, the voltages of multiple incoherent sources add in a 
root-sum-squared (RSS) fashion.  The voltage of the sum of eight incoherent 
sources is square root of eight times a single noise source, assuming equal 
combining ratios.  However, because power is proportional to the square of 
voltage, then the *power* of the combined sum is the sum of the individual 
noise powers.  This is well known in the theory of random processes, which is 
the basis of communications theory.  So, what I said earlier is correct.  For a 
system with eight amplifiers, the effective total noise power in the sum is 
eight times the individual noise powers when the sources are combined with 
equal weights.  The YCCC array does not use equal weights, so the powers have 
be weighted when combining them to get the total noise power.

73, John W1FV


-Original Message-
From: Lee STRAHAN mailto:k7...@msn.com>>
To: topband@contesting.com<mailto:topband@contesting.com> 
mailto:topband@contesting.com>>
Sent: Wed, Mar 11, 2020 10:22 pm
Subject: Re: Topband: Hi Z amplifiers for 160m
  Hello John and all,
  Concerning the adding the noise in a typical array. If the noise was coherent 
or exactly the same signal from each element/amp the summed noise would indeed 
be 8 times. However circuit noise is always random and incoherent which causes 
the summation to be a single noise power times the square root of the number of 
elements assuming equal levels from each amp. In the case of 8 elements 4.5 dB 
increase which is no small matter as well. In the case of the three elements 
the noise summation would be about 2.4 dB higher than a single element.
Lee  K7TJR  OR

As the designer of the YCCC high impedance feedpoint amplifier, let me address 
some issues related to the design of the YCCC amplifier as well as feedpoint 
amplifiers in general.  If you don't want to read a lot of technical 
gobbledygook, please disregard this message.

The YCCC uses an AD8055 RF amp as the gain element.  As Lee, K7TJF, points out, 
there are most certainly better op amps out there.  However, the AD8055 was the 
"best" part I could find in a DIP-8 package.  The "better" op amps are all SMT 
parts but given that the YCCC preamp was a kit, I intentionally limited the 
selection to DIP-8 parts that kit builders could work with relatively easily on 
a PCB.  Not everyone is able to do a competent job soldering tiny SMT parts.

Within the universe of available RF op amps, tradeoffs must be made in terms of 
noise, linearity, and bandwidth.  The AD8055 is not the lowest noise part but 
it has excellent linearity and plenty of bandwidth for HF use.  At my QTH there 
is an AM BCB station 3 miles away, which makes it a somewhat challenging EMI 
environment.  The decision to run the op amp in a unity gain configuration 
comes down to linear dynamic range.  It is easy to design for more gain, but it 
is also easily demonstrated that you will begin to suffer in terms of unwanted 
intermods.  With the YCCC preamp, I get absolutely zero BCB intermods or 
distortion products in the 160m band at my QTH.

In general I do not like to use an outboard preamplifier between the output of 
the phased array combiner circuit and my receiver because it degrades the 
linear dynamic range of the system.  The YCCC system user's manual (Section
12.1) does specify several outboard preamps that could be used.  In a low EMI 
environment, I think they all work fine.  However, at my QTH, with the nearby 
AM BCB station, all of them, without exception, generate increased distortion 
and intermod, which I find unacceptable.

It is always desirable to apply RF gain with a roofing filter in front, which 
is becoming common practice in high performance receivers.  With my K3S 
receiver, the use of a unity gain antenna feedpoint preamplifier is perfectly 
fine if you also turn on the preamp in the K3S.  This gives the best overall 
linear dynamic range with a preamplified short vertical system.
There is no loss in noise performance because the noise on 160 and 80 is 
totally dominated by atmospheric noise.  In measurements I made at my QTH, the 
internal noise of the YCCC preamp is about 10 dB lower than my d

Re: Topband: Hi Z amplifiers for 160m

[Lee STRAHAN]

  Mouser 601- 25-7630  or  601-25-7660
[Lee  K7TJR] 

 >>>Use an F connector (a high quality one that can be torqued.)

Can you point to a place that sells them. I became a 'fan' of F termination, 
but have recently had second thoughts because of the bulkhead connector's 
quality.

Thanks and 73.

Vince, VA3VF
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Re: Topband: Hi Z amplifiers for 160m

[Lee STRAHAN]

Greetings all,
   George has some very pertinent points here and only on one point I will 
disagree. What a Hi-Z amplifier needs to do is dependent on your aspirations of 
the size and quantity of elements you decide to use. The combiner losses will 
dictate what you must do at the element end of an array for an amplifier. Let 
me clear one thing up. The YCCC amplifier is not a unity gain amplifier. It has 
a 6 dB loss due to its output impedance of around 75 ohms. Thus the evolution 
of what I called the +6 amps 6 or 7 years ago that indeed have unity gain and 
still have a 75 ohm output impedance. A significant reduction in the noise 
figure of an array with a lossy combiner.
   If ones aspirations are only to use a simple array like the YCCC then the 
operational amplifier versions seem to fill the bill, but don't expect then to 
apply the same amplifiers as you build arrays for higher and higher RDF. And, 
there are much better amplifiers available to replace the 8055 if I remember 
the YCCC part number correctly. The 8055 has like 4nV/root Hz noise while some 
of the new ones get down to 1 nV/root Hz noise a very significant improvement.
   I could bore you all to distraction with other fine points that Hi-Z amps 
need as specifications. It may not meet the eye but that is why performance 
comes at a price.

Lee   K7TJR
Hi-Z Antennas




Chris,
Assuming a trans-impedance amplifier, "unity gain" is enough (with reasonable 
size elements). Noise and IP3 are far more important. Lightning and surge 
immunity are also important. Also, isolate the amp from common mode noise 
travelling on the feed-line. Filter the power supply well. Use an F connector 
(a high quality one that can be torqued.) GL and 73, George, AA7JV/C6AGU

On Wed, 11 Mar 2020 11:33:34 +
  Chris Moulding  wrote:
> As well as being a radio amateur (G4HYG) I also run a small business 
> designing and making radio equipment (Cross Country Wireless).
>
> Recently I've been asked by a radio contest group to see if I can redesign 
> the YCCC Hi Z amplifier using modern components and using similar mounting 
> arrangements to our Loop Antenna Amplifier.
>
> The first prototype using surface mount components is working well.
>
> So far I've not build an array of antennas but that will come later when the 
> production boards arrive.
>
> The prototype uses a unity voltage gain amplifier and a BNC connector.
>
> I've a couple of questions for others on the list with experience of running 
> vertical receive arrays:
>
> Is a unity voltage gain amplifier OK or do you think it needs more gain for 
> long coax runs?
>
> At present I'm using a BNC male connector for the output. Would an F type 
> connector be more compatible with existing antenna arrays.
>
> 73, Chris G4HYG
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband 
> Reflector

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Topband: RG-6 Delay cables

[Lee STRAHAN]

Good morning from Oregon Top-Band people,
  I decided to re-do some previous tests of the common 75 ohm RG-6 
cable I use and is used for delay cables in many places for top-band receiving 
systems.
I just thought I would share the results of yesterday's tests.
 I took a delay cable that I had used in the field here several times. The 
temperature in my shack at the time was only 59 degrees measured on the coaxial 
cable itself with a non-contact meter.
  I did an OS ( Open Short) feed through calibration with minimum loss 50 to 75 
ohm conversion pads installed on my VNA. Calibration was done immediately 
before each test below, so two calibrations were done.
  The cable under test measured 74.59 degrees delay at 1840 KHz initially.
I watched the VNA make 10 sweeps, each about 10 seconds long for 10 
observations of phase delay for two cable temperature tests.
 This particular cable was imported by the Steren Co. for sale in The USA, part 
number 200-931 .
 After the first test at 59 Deg. F I chucked the cable into the food freezer 
preparing for the second. One and one half hours later the cable surface temp 
measured between 20 and 25 Deg. F

Cable loss was -.61 dB at 59 Deg. F,  And -.58 dB at an averaged cable 
temperature of 23 Deg. F.
59 Deg. F  23 Deg. F
1 - 74.59 DEG  -74.60  DEG.
2 - 74.59 DEG -74.60  DEG.
3 - 74.59 DEG -74.60  DEG.
4 - 74.59 DEG -74.60  DEG.
5  -74.60  DEG -74.60  DEG.
6 -74.60  DEG  -74.60  DEG.
7 -74.60  DEG  -74.60  DEG.
8 -74.60  DEG  -74.60  DEG.
9 -74.60  DEG  -74.60  DEG.
10 -74.60  DEG-74.60  DEG.

My bottom line conclusion is that for our purposes on the top-bands I no longer 
wonder if the cable delay and attenuation remained constant with winter 
deployed arrays.
Incidentally, T Snap and Seal have been the best connectors here for 
repeatability.

Lee Strahan
K7TJR

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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: RG-6 Delay cables

[Lee STRAHAN]

Robin WA6CDR mentioned this to me in an earlier exchange this AM. It was not 
me. Should have mentioned that before. Sorry Robin, You the Man!
Lee   K7TJR

-Original Message-
From: Richard (Rick) Karlquist  
Sent: Wednesday, April 8, 2020 2:00 PM
To: Lee STRAHAN ; topband@contesting.com
Subject: Re: Topband: RG-6 Delay cables



On 4/8/2020 1:28 PM, Lee STRAHAN wrote:

> Even if the copper center conductor expands, the way the cable connectors 
> are made allows the copper to simply push in the connector  past the 
> connection point maintaining its physical length.

Very astute.  You may have explained this paradox.
I didn't think of this type F effect.  Some type N connectors also work this 
way.

73
Rick N6RK

_
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Re: Topband: RG-6 Delay cables

[Lee STRAHAN]

Hi Mike,
   I make the Hi-Z Antennas receiving arrays and I am always looking for ways 
to make them work better. Attention to detail has been the key to success in my 
endeavors. I had made some early tests on this cable going on 15 years ago when 
I did not have as good equipment.  As I design or redesign things I find modern 
technology has paved the way for even better performance. Here is the 
situation. The 8 element all active array whose model shows 13.48 dB RDF 
remains the top of the list as far as I know for that performance. What I do 
know about that also is mathematically those 8 elements theoretically can 
produce an RDF of right at 16 dB. The rub is the element amplitudes and phasing 
has to be controlled to some remarkable unobtainable accuracies to do that. 
Just maintaining 2% amplitude accuracy and 1 or 2 degrees phase stability  10 
years ago when the 8 array was put into production was all I thought I could 
squeak out with the then current components and measuring ability I could a
 fford. Buying 1% resistors and capacitors in surface mount is now common which 
has helped available accuracies and my test equipment is much better than I had 
at the time. Chasing these things is part of what I do trying to push the 
barriers of low band Receiving.
 It has always been in the back of my mind that not knowing accurately the 
stability of the delay cable was one of the error terms greatly affecting how 
the array could match the model. Just something that had to be done in my mind.
 Here is some more shocking cable data I took several years ago  
https://www.k7tjr.com/coaxial_tests.htm  
Cheers,
Lee   K7TJR OR

-Original Message-
From: Topband  On Behalf Of Mike 
Smith VE9AA
Sent: Wednesday, April 8, 2020 11:49 AM
To: topband@contesting.com
Subject: Re: Topband: RG-6 Delay cables

Interesting Lee.  I guess I never thought anything about delay lines in our 
weather here.  I have RG-6-like cables on all my 4-squares.

I was unaware electrons cared whether it was +35*C or -35*C (or general temp 
range here in NB)

 

What prompted you to do such testing?

 

Thanks

 

Mike VE9AA



".My bottom line conclusion is that for our purposes on the top-bands I no 
longer 

wonder if the cable delay and attenuation remained constant with winter 

deployed arrays.

Incidentally, T Snap and Seal have been the best connectors here for 

repeatability.

 

Lee Strahan

K7TJR."

 

 

 

Mike VE9AA

 

 

Mike, Coreen & Corey

Keswick Ridge, NB

 

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Re: Topband: RG-6 Delay cables

[Lee STRAHAN]

Hi Rick,
   Agreed, the numbers surely seemed too good to be true. I also researched 
cable delays versus temperature at various manufacturers. I found no data at 
the low bands we use. I found just enough information to make me do the test. I 
am confident the answers I recorded are correct. I did not look at higher 
frequencies with the VNA. Teflon cable is the only one I found that had a 
nonlinear curve so rejected that idea as I don’t use Teflon for this.
  There are way too many things going on with the cable construction to 
estimate in my mind. That’s why I did the test. I also reaffirmed that after 
the cold test the cable loss returned to the starting point.
Perhaps someone else would care to look at the cable.
   Even if the copper center conductor expands, the way the cable connectors 
are made allows the copper to simply push in the connector  past the connection 
point maintaining its physical length.
   Again way to many things and so I did the tests.  I think I will put the 
cable in the freezer again and do the tests again which seems like the right 
thing to do. Am confident the VNA is accurate. I have some short pieces of 
cable and I will add some cable to the DUT to verify the VNA sees the 
difference. 
 I will report on this again soon.
Lee   K7TJR.

These numbers seem too good to be true.
The tempco works out to less than 7 PPM/°C.
Consider that the coefficient of thermal expansion of copper is +17PPM/°C.

Refer to Figure 7 of this:

https://www.timesmicrowave.com/DataSheets/Literature/Current%20innovations%20in%20phase%20stable%20coaxial%20cable.pdf

The graph on the right shows non-linear tempco curves.
When you have non linearity like this,
it is possible to pick two points on the curve such that a line drawn through 
them has a slope of zero.
Maybe you ran into that.

The numbers you reported for the loss seem roughly consistent with what the 
thermal coefficient of resistance of copper predicts.

Rick N6RK
_
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Re: Topband: RG-6 Delay cables

[Lee STRAHAN]

More on the cable testing,
Thinking along the lines Rick was I decided to retest the same cable to see 
if the results were repeatable.
The original phase shift for both room temperatures was 59 deg. F and 23 deg. F 
 Results were -74.6 degrees and -0.61 dB to  -74.6 deg and  -0.58 dB loss warm 
to cold.
  VNA calibration was used at the start of each test again.
 Several hours after that test the room and cable were up to 61 deg. F . The 
second round of tests began.
The first test of phase delay matched the early tests with  -74.59 to -74.60 
degrees again with loss at -0.617 dB. Very close to the original tests.
 I decided to add 4 inches of cable to verify small changes in the 
readings. The reading then was -74.89 deg with loss of -0.618 db.
After freezing the cable for another couple hours the temp of it was again 
average 23 deg. F . Verified with a thermocouple meter and non-contact device.
The cable  phase delay was -74.62 deg.  with a loss of -0.517 db . This leaves 
some question on the loss number. Perhaps some cable tightening issue or 
misreading.
 I added the same 4 inch cable to the cold cable.
The result was -74.97 deg and -0.582 db loss. Loss matches the original tests.
 All this very respectable data with all the connector connecting and 
disconnecting and just finger tightening the connectors. I probably should have 
torqued them for the best result.
 As I mentioned before I think I am going to not worry about significant cable 
phase delay and loss changes with temperature. 
   Regards all and thanks for the tips and the bandwidth,  73
Lee   K7TJR  OR




On 4/8/2020 1:28 PM, Lee STRAHAN wrote:

> Even if the copper center conductor expands, the way the cable connectors 
> are made allows the copper to simply push in the connector  past the 
> connection point maintaining its physical length.

Very astute.  You may have explained this paradox.
I didn't think of this type F effect.  Some type N connectors also work this 
way.

73
Rick N6RK

_
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Re: Topband: Loop on the ground as a counterpoise

[Lee STRAHAN]

Greetings All,
   It seems this discussion has morphed into a discussion on ground planes for 
regular vertical antennas where if I read the authors description correctly he 
is using a Hi-Z amplifier. This may mean a whole different ground system would 
be very satisfactory. I believe it was Sinisa YT1NT, VE3EA that mentioned there 
was a great deal more information needed to understand any noise changes due to 
using a loop antenna for a ground on a Hi-Z element. I agree with Sinisa. Frank 
W3LPL was right on when he mentioned the ground screen as a possibility. Two 
very important things about using a Hi-Z amplifier with a short vertical are 
the need for serious common mode rejection at the amplifier output and a very 
high input impedance consisting of a high resistance and a very low 
capacitance. Typically the amplifiers I am familiar with have a 43Kohm or more 
parallel resistance and about 10 to 15 pf parallel input capacitance. A typical 
shortened vertical an inch in diameter and 24 feet in length w
 ill exhibit an output source impedance that is very high. It consists of a 
very low series resistance of an ohm or two and a series capacitance of about 
80+ pf. Looking at 85pf driving 10 to 15 pf amplifier input capacitance does 
not require a super counterpoise around the element for the ground terminal on 
the amp. A rather large capacitance or very low resistance to mother earth will 
both suffice. The only fly in the ointment is if the ground system for this 
Hi-Z element is resistive dominant and goes much above about 40 ohms resistance 
which then appears in series with the element driving the amp, the received 
signal begins to be phase shifted causing a possible difference from one 
element to another. Not good in an array of elements. 
   As far as the noise changing with a loop as a radial or counterpoise I have 
not seen anything that would make me believe the loop configuration was 
responsible. I would rather think it was lowered counterpoise resistance or 
lack of common mode isolation in the amp having lowered noise. This could also 
come from other close antenna installations radiating noise into the single 
wire more so than the loop due to the common angle of a radiating noise source 
like a large antenna radial, fence or power line. A good Hi-Z amplifier with 
lots of common mode isolation will act very much like a differential amplifier 
which means the noise could come from either direction, the ground terminal 
(loop) or the element. It is my experience that in very dry and or rocky soil 6 
to 8 ground radials no longer than the length of the element in addition to a 
ground rod will work quite nicely.
   It will be most interesting as Chris continues on with these loops as a 
counterpoise and reports more of his observations from experimentation. Perhaps 
there is indeed something new...
Lee  K7TJR   OR

-Original Message-
From: Topband  On Behalf Of Chris 
Moulding
Sent: Monday, May 4, 2020 1:58 AM
To: topband@contesting.com
Subject: Topband: Loop on the ground as a counterpoise

I've developed a High Z Antenna Amplifier for 160m and other HF use as 
previously mentioned on the list.

Usually these would be used with a ground rod and 5m vertical element.

With the lockdown it's not possible to nip to the shops for a ground rod so I 
looked at supplying a 10m wire as a counterpoise.

At home and the workshop I have Loop on the Ground antennas from previous 
antenna experiments so I also tried using these with both ends of the loop 
connected to the amplifier ground terminal.

On testing this gave significantly better signal to noise ratios than using a 
ground rod or a single wire counterpoise. Checking with a SDR receiver I could 
see that the usual local VDSL internet hash had disappeared.

Both loops on the ground are 3m or 10' square.

I've also tried it using a G7FEK vertical antenna at home with two 3m or 10' 
square loops on the ground with similar results seeing much reduced local noise 
compared with the ground radials I had before. Topband Dx might be a 
possibility for me now.

I've never seen this mentioned in ham magazines before and I can't find 
anything with an internet search. Usually I find that all my good ideas have 
already been thought of 50 years ago.

I suspect that the RF voltage in the loop counterpoise is much reduced over the 
voltage at the end of a radial wire reducing noise pickup in the radial system.

I would like to model the loop on the ground counterpoise in a modelling tool. 
I use 4NEC2 but only have access to NEC2 so wires on the ground don't model 
correctly.

Is there any one out there with access to suitable software that could model it 
for me?

73, Chris G4HYG




   

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Re: Topband: Slightly OT - amplifier noise

[Lee STRAHAN]

  Don’t forget there is gain in the signal paths. That first AUX input stage is 
a Norton configuration amp with gain controlled by the unknown transformer 
ratios. The two J-310's that sum the signals also appear to have a few dB gain. 
A full analysis of the circuit is necessary to derive what the insertion gain 
of this device would be. Or a measurement might be in order with gain pots at 
max. It could be amplified input device noise at the output.
Lee   K7TJR

-Original Message-
From: Topband  On Behalf Of Dave 
Cuthbert
Sent: Monday, March 16, 2020 2:05 PM
To: n...@arrl.net
Cc: Topband ; Guy Olinger K2AV 
Subject: Re: Topband: Slightly OT - amplifier noise

Steve,

I performed a hand calculation of the MFJ-1025 14 MHz noise and it's (only)
9 nV/Hz^0.5, or 0.2 uV in 500 Hz. This is -120 dBm, or S-1. But you measure
S-4 noise. What is going on?

Questions to determine what is going on:

Question 1) What model is the radio?
Question 2: What bandwidth is the noise measured with?
Question 3: What band?
Question 4: What does the radio  measure connected to the MFJ-1025 but with 
the MFJ powered OFF?


*MFJ-1025 termination *
With the two MFJ-1025 antenna terminals left open the two JFET inputs are 
terminated in 0-78 ohms depending on the gain pot settings. Note that gain pots 
reduce the signal but not JFET noise and cutting the gain degrades the S/N 
ratio. With the gain pots at maximum the unterminated input noise from the 
resistors is (only) 1.1 nV/Hz^0.5.

*MFJ-1025 noise calculations*
Let's add up all the noise sources and derive the 14 MHz noise.

*Q4 output buffer*
   Q5 voltage gain, 1
   1 nV/Hz^0.5 transistor (my estimate; I can calculate it but it's low enough 
to just call it 1 nV/Hz^0.5)
   1.9 nV/Hz^0.5 for R8 (220 ohms)
   Total input noise 2.2 nV/Hz^0.5 (the transistor noise is my estimate)
   Total output noise 2.2 nV/Hz^0.5

*Q5, Q6 active combiner*
   Q5 voltage gain, 1.1
   R9||R26, 1.1 nV/Hz^0.5
   Q5 gate, 0.6 nV/Hz^0.5
   Input noise, 1.3 nV/Hz^0.5
   Output noise, 1.4 nV/Hz^0.5

   Q6 voltage gain, 2.3
   R13, 1.9 nV/Hz^0.5
   Q6 gate, 0.6 nV/Hz^0.5
   Input noise, 2.0 nV/Hz^0.5
   Output noise, 4.6 nV/Hz^0.5

   Q5 + Q6 noise
   Output noise, 4.8 nV/Hz^0.5

   *Q7 phase splitter*
   Q7 voltage gain, 1
   Q7 gate, 0.6 nV/Hz^0.5
   R13, 1.9 nV/Hz^0.5
   Output noise, 2.0 nV/Hz

   *Q8 AUX amp *
   Q8 voltage gain, 2 (that's a guess)
   R20||R27, 1.1 nV/Hz^0.5
   Q8 gate, 0.6 nV/Hz^0.5
   Input noise, 1.3 nV/Hz^0.5
   Output noise, 2.6 nV/Hz^0.5

*Adding it up*
The noise into Q6 is the AUX amp (2.6 nV/Hz^0.5) + the phase splitter (2.0
nV/Hz) = 3.3 nV/Hz^0.5

The noise out of Q6 is X2.3 the input noise = 7.5 nV/Hz The noise out of Q5 is 
4.8 nV/Hz^0.5 Adding two these together the noise into Q4 is 8.9 nV/Hz Add 1 
nV/Hz^0.5  for Q1 and we have 9.0 nV/Hz

The MFJ-1025 *output noise is 9 nV/Hz^0.5*

In a 500 Hz BW this is 200 nV, or 48 dB below S-9. *This is S-1*.
The AUX-referred noise is ~1.7 nV/Hz^0.5 The MAIN-referred noise is ~8 nV/Hz^0.5

*12V Power is well decoupled*
The 12V power is well decoupled with 14 MHz PS rejection ratio of 110 dB.
This is calculated for bypass cap C7 having 10 nH lead inductance. So, I don't 
see that noise on the 12V source makes a difference.

*LTSpice J310 noise model issue*
I ran sims of a J310 JFET in a simple source-follower circuit and LTSpice 
reports noise that is so far off it's unusable. Instead I use a claimed noise 
figure of 3 dB. If I use the specified 100 Hz noise of 10 nV/Hz^0.5 the output 
noise rises enough to make S-4 noise. But, I believe the 100 Hz noise is below 
the J310 1/f frequency and is much higher than the HF noise.
I think I can calculate the 1/f frequency to make sure. About 10 years ago I 
designed a test setup to measure MOSFET noise and ran thru the calculations for 
1/f and noise.

*References*
MFJ-1025 manual with schematic:
https://www.mfjenterprises.com/support.php?productid=MFJ-1025

J310 datasheet:
http://pdf.datasheetcatalog.com/datasheet_pdf/intersil/J308_to_J310.pdf

J310 RF amp noise figure: http://receiverforjupiter.tripod.com/rfamp.htm

Dave KH6AQ


On Mon, Mar 16, 2020 at 8:33 AM Steve London  wrote:

> I did that - terminated in 50 ohms.
>
> 73,
> Steve, N2IC
>
> On 03/16/2020 12:27 PM, Guy Olinger K2AV wrote:
> > Depending on the exact circuit and device, to measure noise from the
> device
> > itself, don’t you have to terminate the inputs to put the normal
> impedance on
> > them? The circuits are often designed with the coax Z zero in mind.
> >
> > 73, Guy K2AV
> >
> > On Mon, Mar 16, 2020 at 12:47 PM Steve London  > > wrote:
> >
> > This has been a very interesting thread - Thanks for all the input.
> >
> > Perhaps I have set my expectations too high.
> >
> > A typical application is on 15 meters, late in the opening, 
> > working
> JA's from
> > here in SW New Mexico. Absent any local QRN, the band is very quiet.
> 

Re: Topband: Slightly OT - amplifier noise

[Lee STRAHAN]

Hi Dave,
In my experience that is not a typical Norton amplifier gain . Most would be 
considerably in excess of that at 11  or 19 dB. They can run from 5 to 19 dB or 
so but what would be the purpose of only putting 5 dB there with an expensive 
amplifier configuration?  The ones I use are 11 dB gain. Just my $.02
Lee K7TJR

From: Dave Cuthbert 
Sent: Monday, March 16, 2020 3:05 PM
To: Lee STRAHAN 
Cc: topband@contesting.com
Subject: Re: Topband: Slightly OT - amplifier noise

Circuit gain is accounted for in my calculations. I ran a sim of the input amp 
and could get it to work with gains from 0.5 to 2 using different transformer 
ratios. So, I think the gain-of-2 I used is good enough.

On Mon, Mar 16, 2020 at 11:32 AM Lee STRAHAN 
mailto:k7...@msn.com>> wrote:
  Don’t forget there is gain in the signal paths. That first AUX input stage is 
a Norton configuration amp with gain controlled by the unknown transformer 
ratios. The two J-310's that sum the signals also appear to have a few dB gain. 
A full analysis of the circuit is necessary to derive what the insertion gain 
of this device would be. Or a measurement might be in order with gain pots at 
max. It could be amplified input device noise at the output.
Lee   K7TJR

-Original Message-
From: Topband 
mailto:msn@contesting.com>> 
On Behalf Of Dave Cuthbert
Sent: Monday, March 16, 2020 2:05 PM
To: n...@arrl.net<mailto:n...@arrl.net>
Cc: Topband mailto:topband@contesting.com>>; Guy 
Olinger K2AV mailto:k2av@gmail.com>>
Subject: Re: Topband: Slightly OT - amplifier noise

Steve,

I performed a hand calculation of the MFJ-1025 14 MHz noise and it's (only)
9 nV/Hz^0.5, or 0.2 uV in 500 Hz. This is -120 dBm, or S-1. But you measure
S-4 noise. What is going on?

Questions to determine what is going on:

Question 1) What model is the radio?
Question 2: What bandwidth is the noise measured with?
Question 3: What band?
Question 4: What does the radio  measure connected to the MFJ-1025 but with 
the MFJ powered OFF?


*MFJ-1025 termination *
With the two MFJ-1025 antenna terminals left open the two JFET inputs are 
terminated in 0-78 ohms depending on the gain pot settings. Note that gain pots 
reduce the signal but not JFET noise and cutting the gain degrades the S/N 
ratio. With the gain pots at maximum the unterminated input noise from the 
resistors is (only) 1.1 nV/Hz^0.5.

*MFJ-1025 noise calculations*
Let's add up all the noise sources and derive the 14 MHz noise.

*Q4 output buffer*
   Q5 voltage gain, 1
   1 nV/Hz^0.5 transistor (my estimate; I can calculate it but it's low enough 
to just call it 1 nV/Hz^0.5)
   1.9 nV/Hz^0.5 for R8 (220 ohms)
   Total input noise 2.2 nV/Hz^0.5 (the transistor noise is my estimate)
   Total output noise 2.2 nV/Hz^0.5

*Q5, Q6 active combiner*
   Q5 voltage gain, 1.1
   R9||R26, 1.1 nV/Hz^0.5
   Q5 gate, 0.6 nV/Hz^0.5
   Input noise, 1.3 nV/Hz^0.5
   Output noise, 1.4 nV/Hz^0.5

   Q6 voltage gain, 2.3
   R13, 1.9 nV/Hz^0.5
   Q6 gate, 0.6 nV/Hz^0.5
   Input noise, 2.0 nV/Hz^0.5
   Output noise, 4.6 nV/Hz^0.5

   Q5 + Q6 noise
   Output noise, 4.8 nV/Hz^0.5

   *Q7 phase splitter*
   Q7 voltage gain, 1
   Q7 gate, 0.6 nV/Hz^0.5
   R13, 1.9 nV/Hz^0.5
   Output noise, 2.0 nV/Hz

   *Q8 AUX amp *
   Q8 voltage gain, 2 (that's a guess)
   R20||R27, 1.1 nV/Hz^0.5
   Q8 gate, 0.6 nV/Hz^0.5
   Input noise, 1.3 nV/Hz^0.5
   Output noise, 2.6 nV/Hz^0.5

*Adding it up*
The noise into Q6 is the AUX amp (2.6 nV/Hz^0.5) + the phase splitter (2.0
nV/Hz) = 3.3 nV/Hz^0.5

The noise out of Q6 is X2.3 the input noise = 7.5 nV/Hz The noise out of Q5 is 
4.8 nV/Hz^0.5 Adding two these together the noise into Q4 is 8.9 nV/Hz Add 1 
nV/Hz^0.5  for Q1 and we have 9.0 nV/Hz

The MFJ-1025 *output noise is 9 nV/Hz^0.5*

In a 500 Hz BW this is 200 nV, or 48 dB below S-9. *This is S-1*.
The AUX-referred noise is ~1.7 nV/Hz^0.5 The MAIN-referred noise is ~8 nV/Hz^0.5

*12V Power is well decoupled*
The 12V power is well decoupled with 14 MHz PS rejection ratio of 110 dB.
This is calculated for bypass cap C7 having 10 nH lead inductance. So, I don't 
see that noise on the 12V source makes a difference.

*LTSpice J310 noise model issue*
I ran sims of a J310 JFET in a simple source-follower circuit and LTSpice 
reports noise that is so far off it's unusable. Instead I use a claimed noise 
figure of 3 dB. If I use the specified 100 Hz noise of 10 nV/Hz^0.5 the output 
noise rises enough to make S-4 noise. But, I believe the 100 Hz noise is below 
the J310 1/f frequency and is much higher than the HF noise.
I think I can calculate the 1/f frequency to make sure. About 10 years ago I 
designed a test setup to measure MOSFET noise and ran thru the calculations for 
1/f and noise.

*References*
MFJ-1025 manual with schematic:
https://www.mfjenterprises.com/support.php?productid=MFJ-1025

J310 datasheet:
http://pdf.datasheetcatalog.com/datasheet_pdf/intersil/J308_to_J310.pdf

Topband: RX Power over Coax

[Lee STRAHAN]

 Hi Dennis and top band interested folks,
   The very first amps I made for myself were using an external power wire. 
Using external power required some pretty heavy choking on each end of that 
added wire. I started experimenting with power over the signal coax. I could 
not see or measure any difference in noise floors with usually new components 
including coax. After a number of years' experience I now believe that if there 
was a weakened connection that would allow micro arcing then that same 
weakening would cause a perturbation in the operation of the array also. This 
resultant lack of performance would signal the operator that something was 
wrong. All the elements in most of my designs are required to operate and feed 
signal continuously to the combiner regardless of the direction selected so all 
would be susceptible. It's my opinion as I have not witnessed any arc sounding 
interference or noise floor increase that I could not identify as external to 
the array. Keep in mind I have not done yearlong in depth projects to verify my 
observations or real levels of possible noise. I am sure a fully loaded 
environmental laboratory could do this but so far I cant.
 If one desired to power the amplifiers externally any noise current that 
would be developed on a single wire must then also flow into the power terminal 
where it would encounter a generally large filtering capacitor across the power 
rails of the amp and its ground side. The noise current would then flow right 
through to the amp ground terminal and be impressed upon the array ground rod. 
This also is not a desirable thing as the ground rods exhibit impedance and a 
noise voltage could then show up as added to the element signal. Series 
inductance in this line can help. So it appears the best answer to this is to 
use a second coaxial cable or 2 wires to supply the voltage and power ground to 
the amp. Now with both + power and ground wires feeding power to the amp one 
can use common mode filtering to remove the noise flowing to ground and an 
additional inductance to decrease any noise voltage on the center of the coax 
carrying the plus power voltage.
   Its true, I have built a couple versions of Hi-Z amps with RG-6 external 
power connections for Tim at K3LR. He has serious common mode filtering on 
these power lines as well as the signal lines and I suspect serious filtering 
on the supply voltage as well. There may in my mind be some advantage of 
external power in keeping multiple transmitter signals off the array power as 
well. 
   Its also true that I have a small circuit board I can install on the back of 
a second coax connector on the New version SMD amps. The board offers 5000 ohms 
of common mode protection on 160M and a series inductance for the center wire 
providing 1 mHy inductance giving some isolation for power supply or induced 
center conductor noise. No need for expensive giant ferrite cores on the coax 
lines. Common mode protection is built in to both the coax power input and the 
coax signal output.
So due to lack of interest I have not championed the idea of providing this 
external power capability. I think the reputation of success with Hi-Z and its 
power over coax stands for itself as to the existence of the problem at Hi-z or 
the public would be letting us all know something is wrong. Trust me on that. I 
cant speak for any other designs.
In addition to this noise incursion possibility I have uncovered another 
possibility of micro arcing unrelated to the coax. As it stands most of these 
arrays are powered from an in shack power supply. With some of these arrays 
drawing 1/2 an amp or more if using a wireless remote relay setup. This causes 
a significant voltage drop on power wires leading to the array. With the power 
supply grounded at the shack and the Hi-Z amps grounded at the array elements 
there is often a voltage difference between shack ground and element ground 
caused by the power supply current flow. This voltage difference causes a 
current flow in the ground rod. In more than 18 years of operation I will soon 
have to replace my original Steel Tee post mounted elements as the ground end 
of the posts has been eaten away by what I assume to be electrolysis. My theory 
is that there could be noise developed on the ground rod at the element caused 
by this voltage dropped between the shack and the array causing the 
electrolysis. Noise on the ground rod shows directly up as received signal. My 
new version of SMD amps have been designed so that DC voltage will not be sent 
to the ground rod at the elements. If anyone has experienced noise as a result 
of the power over coax with a Hi-Z array I would welcome information of the 
circumstances. Come to think of it,  I believe I have a new amp with external 
power laying around here. I will make it a point to see if I can identify any 
noise difference between amps with and amps without External power. This will 
make an 

Topband: FW: CQWW a bust this year

[Lee STRAHAN]

Hmmm, Nick,
  I beg to differ with you. I don’t care about scores or countries, zones  
worked but I do care about 160 meter receiving antennas.
In my opinion your statement is dead wrong.
Not looking for a war of words or any more discussion. I will not respond again 
about this.

Lee   K7TJR
Hi-Z Antennas



-Original Message-
From: Topband  On Behalf Of uy0zg
Sent: Tuesday, December 1, 2020 7:10 AM
To: peter.voel...@t-online.de
Cc: topband@contesting.com; Topband 

Subject: Re: Topband: CQWW a bust this year

Dr Peter

Super RX antennas for 160 m do not exist!

Exist  :
- good conditions
- Quiet countryside
-  Geography

Does not exist :

- Miracles



I never envy. They envy me!




In CQ WW I only heard three from the USA - K7GM, W1KM, W3UA.

These are honest QSOs.



---
Nick, UY0ZG
http://www.topband.in.ua

dj...@t-online.de писал 2020-12-01 16:38:
> It´s amazing, the probably envious stations always suspect others with 
> their better antennas and perhaps better operation to use web sdr.
> 
> 73
> Peter
> 
> -Original Message-
> From: Topband
> [mailto:topband-bounces+dj7ww=t-online...@contesting.com]
> On
> Behalf Of uy0zg
> Sent: Dienstag, 1. Dezember 2020 14:19
> To: Tom | SP5XO
> Cc: topband@contesting.com; Topband
> Subject: Re: Topband: CQWW a bust this year
> 
> Hi
> 
>   Weeks conditions ?
> 
> For the best of the ex USSR countries, this is not a problem!
> 
> 
> Very good HIGH + WEB SDR+ very kind and democratic American judges  =
> 
> 
> super result is ready!
> 
> http://lists.contesting.com/archives//html/3830/2020-11/msg08693.html
> 
> 
> .
> 
> 73 !
> 
> ---
> Nick, UY0ZG
> http://www.topband.in.ua
> 
> Tom | SP5XO ? 2020-12-01 14:21:
>> Compare to recent weeks conditions were marginal during CQWW. Only 
>> two Zone
>> 4 stations were audible here and it took long time to work them.
>> Whereas a
>> week ago band was wide open from MI, IL to CO or even down to TX.
>> I worked only mults and Dx's this time. Only 13 stations from Zone 5 
>> in my log. Except for VY2ZM all NA's were weak including KC1XX and 
>> W3LPL!
>> Hopeful things improve for next weekend and will work some more in 
>> ARRL 160.
>> CU
>> Tom
>> sp5xo
>> 
>> Conditions certainly didn't favor 160 over the weekend CQWW contest 
>> here in
>>> Florida at least.
>>> 
>>> Looking back in 2019 I worked 50 countries on 160 during CQWW, this 
>>> year it was only 17, only 3 Europeans and those were very weak. I'm 
>>> sure the lack of expeditions due to CV-19 played a part but on whole 
>>> I think many guys in hindsight will be glad they didn't spend the 
>>> money to go.
>>> 
>>> Maybe things will pick up next weekend for the ARRL 160 test though 
>>> that tends to be largely a USA to USA test and it is hard to hear 
>>> the DX through the local mob
>>> 
>>> CU guys in the pile up
>>> 
>>> Dave
>>> NR1DX
>>> --
>>> Dave manu...@artekmanuals.com www.ArtekManuals.com
>>> 
>>> 
>>> 
>> _
>> Searchable Archives: http://www.contesting.com/_topband - Topband 
>> Reflector
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband 
> Reflector
> 
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband 
> Reflector
_
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_
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Re: Topband: Looking for a 2n5109

[Lee STRAHAN]

Hi Ed,
   I knew about the 2N3866 and 2N5109 disappearing so I bought a bunch of 
2N3866 while they were still in stock. Same transistor die only with a lower Ft 
of 800MHz instead of 1500 MHz.
 I have used them for years in a similar preamp circuit. I can send you one or 
a few at $3.00 each which is what I paid. And a little postage. 
You are correct, don't buy the Chinese ones as the ones I received were so slow 
they must have been audio transistors.

Lee   K7TJR
Hi-Z Antennas




-Original Message-
From: Topband  On Behalf Of 
Edward stallman
Sent: Thursday, October 22, 2020 9:23 AM
To: topband@contesting.com
Subject: Topband: Looking for a 2n5109

I remember about a year ago a discussion not to buy the 2n5109 transistors from 
E-Bay sellers . Some searching shows the 2n5109 has been discontinued for many 
years . So is anyone that's been saving one for many years willing to part with 
it ? I'm using it in a W7IUV pre-amp .

Thanks Ed N5DG

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_
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Re: Topband: (2wire) Beverage transformers

[Lee STRAHAN]

Hi Don,
Regardless of the transformer whether it’s a tapped or separate. I gave him 
the tools that should make whatever he does correct. Personally I keep my 
Beverage when I make one at 450 ohms which makes the matching much easier for 
me. I just put up my first one yesterday in several years to test a new 
brainstorm antenna.
   From what I saw he had a 1:1.16 SWR which could not get much better in my 
opinion. Apparently he thought it could be better.
All is good  HNY
Lee  K7TJR  OR


From: Don Kirk 
Sent: Saturday, January 2, 2021 1:54 PM
To: Lee STRAHAN 
Cc: HA3LN ; Mike Waters ; topband 

Subject: Re: Topband: (2wire) Beverage transformers

Hi Lee,

Csaba also refers to this transformer as T2 and based on what he has said so 
far I suspect he is constructing something similar to the two direction 
beverage shown in figure 7-115 in the 5th edition of Low-Band DXing.  And T2 is 
indeed a two winding transformer with center tap.  This transformer transforms 
the impedance of the open wire transmission line (745 ohms in Csabas case) to 
the coaxial feedline (75 or 50 ohm).  The center tap is used to feed another 
transformer (T1).

I could be wrong but reading between the lines I probably am correct.

Just FYI,
Don (wd8dsb)

On Sat, Jan 2, 2021 at 4:09 PM Don Kirk 
mailto:wd8...@gmail.com>> wrote:
Hi Lee,

Csaba said his transformer was  " n1=3T/n2=12T tapped @6T ".  This sure sounds 
like a transformer with two separate windings (3 Turns on the Primary, and 12 
Turns on the Secondary and then it also has a center tap on the secondary), but 
I could be wrong.  I think Csaba needs to clarify exactly what his transformer 
is, and his test circuit.

Don (wd8dsb)

On Sat, Jan 2, 2021 at 3:22 PM Lee STRAHAN 
mailto:k7...@msn.com>> wrote:
Hi Mike,
   Assuming that you did not miss that this was a tapped winding and not 
separate windings as Csaba mentioned. I see on reflection that he measured 
1:1.16 on one of his tests. In reality it wont likely get much better than 
that. That test was likely the 3:12 he mentioned using. The high impedance side 
of these transformers are a little unpredictable using simple formulas with 
winding capacitance and magnetizing inductance added in the mix.
  Sometimes I use wire wrap wire if it is not going to be used outside 
otherwise I use #27 high temp motor winding class insulation wire which helps 
keep from shorting the wires to the core. I have the benefit of many part 
spools of motor winding wire scraps from a best friend and Ham in the Motor 
rewinding business. By the way, Norton amplifiers require 1:11:4 which is the 
same problem to solve as they are separate windings in the ones I use. I also 
fit shrink tubing in the Norton amp cores for insulation first. I don’t use 
Teflon because it has a dielectric constant around 5 which increases the 
capacitance from the wire to the core. Its tedious but can be done easily. And 
in the case of the Norton amp it leaves room for a larger wire on the 1 turn 
winding. Yes 4 AND16 for 20 total can be done but yes it takes time and lots of 
patience. For those turns counts I go to # 75 material toroid cores which have 
slightly more winding room but require more turns usually for 160 meter stuff.  
All this probably more than you wanted to know. HNY
Lee  K7TJR  OR

From: Mike Waters mailto:mikew...@gmail.com>>
Sent: Saturday, January 2, 2021 11:44 AM
To: Lee K7TJR mailto:k7...@msn.com>>
Cc: HA3LN mailto:l...@ha3ln.hu>>; topband 
mailto:topband@contesting.com>>
Subject: Re: Topband: (2wire) Beverage transformers

Lee,

What kind of wire do you use that allows that many turns (4t and 16t)?

73 Mike
W0BTU

On Sat, Jan 2, 2021, 1:37 PM Lee STRAHAN 
mailto:k7...@msn.com><mailto:k7...@msn.com<mailto:k7...@msn.com>>>
 wrote:
Hello Csaba,
   I approach this problem this way your impedance ratio is 745/50 ohms or 14.9 
. To get turns ratio use the square root of that which is 3.86 . So round that 
up to 4 as a good turns ratio.
  On a BN73-202 core I usually use a minimum of 4 turns on the 50 ohm side for 
160 meters, so the secondary would need 4 turns ratio times that for 16 turns. 
Therefore 16 turns tapped at 4 turns should work for you. Some will say the 3 
turns on the 50 ohm side should work and the secondary then would be turns 
ratio 4 times that or 12 turns. Therefore 12 turns tapped at 3 turns should 
work well also. Sorry, I do not follow your formula as shown but you can use 
the above and it will work fine as an 800 ohm load to the 745 ohm source. This 
will reflect 745/16 or 46.6 ohms to your cable. SWR for that at the 50 ohm 
cable  is 50/46.6 or 1.07 using resistance only for evaluation.
Lee   K7TJR  OR

-Original Message-
From: Topband 
mailto:msn@contesting.com><mailto:msn@contesting.com<mailto:msn@contesting.com>>>
 On Behalf Of HA3LN
Sent: Saturday, January 2, 2021 4:59 AM
To: 
topband@contesting.com<mailt

Re: Topband: (2wire) Beverage transformers

[Lee STRAHAN]

Hi Mike,
   Assuming that you did not miss that this was a tapped winding and not 
separate windings as Csaba mentioned. I see on reflection that he measured 
1:1.16 on one of his tests. In reality it wont likely get much better than 
that. That test was likely the 3:12 he mentioned using. The high impedance side 
of these transformers are a little unpredictable using simple formulas with 
winding capacitance and magnetizing inductance added in the mix.
  Sometimes I use wire wrap wire if it is not going to be used outside 
otherwise I use #27 high temp motor winding class insulation wire which helps 
keep from shorting the wires to the core. I have the benefit of many part 
spools of motor winding wire scraps from a best friend and Ham in the Motor 
rewinding business. By the way, Norton amplifiers require 1:11:4 which is the 
same problem to solve as they are separate windings in the ones I use. I also 
fit shrink tubing in the Norton amp cores for insulation first. I don’t use 
Teflon because it has a dielectric constant around 5 which increases the 
capacitance from the wire to the core. Its tedious but can be done easily. And 
in the case of the Norton amp it leaves room for a larger wire on the 1 turn 
winding. Yes 4 AND16 for 20 total can be done but yes it takes time and lots of 
patience. For those turns counts I go to # 75 material toroid cores which have 
slightly more winding room but require more turns usually for 160 meter stuff.  
All this probably more than you wanted to know. HNY
Lee  K7TJR  OR

From: Mike Waters 
Sent: Saturday, January 2, 2021 11:44 AM
To: Lee K7TJR 
Cc: HA3LN ; topband 
Subject: Re: Topband: (2wire) Beverage transformers

Lee,

What kind of wire do you use that allows that many turns (4t and 16t)?

73 Mike
W0BTU

On Sat, Jan 2, 2021, 1:37 PM Lee STRAHAN mailto:k7...@msn.com>> 
wrote:
Hello Csaba,
   I approach this problem this way your impedance ratio is 745/50 ohms or 14.9 
. To get turns ratio use the square root of that which is 3.86 . So round that 
up to 4 as a good turns ratio.
  On a BN73-202 core I usually use a minimum of 4 turns on the 50 ohm side for 
160 meters, so the secondary would need 4 turns ratio times that for 16 turns. 
Therefore 16 turns tapped at 4 turns should work for you. Some will say the 3 
turns on the 50 ohm side should work and the secondary then would be turns 
ratio 4 times that or 12 turns. Therefore 12 turns tapped at 3 turns should 
work well also. Sorry, I do not follow your formula as shown but you can use 
the above and it will work fine as an 800 ohm load to the 745 ohm source. This 
will reflect 745/16 or 46.6 ohms to your cable. SWR for that at the 50 ohm 
cable  is 50/46.6 or 1.07 using resistance only for evaluation.
Lee   K7TJR  OR

-Original Message-
From: Topband 
mailto:msn@contesting.com>> 
On Behalf Of HA3LN
Sent: Saturday, January 2, 2021 4:59 AM
To: topband@contesting.com<mailto:topband@contesting.com>
Subject: Topband: (2wire) Beverage transformers

Hi All and HNY for 2021.

Preparing for the CQ160m with new (2 coax) 2-wire beverages to cover the 
missing azimuthal gaps based on LBDX. The first 2x Bevs worked great back in 
last Jan.

Now I have difficulties with reaching good imped match with the
T2 transformer (responsible to transform the 745 Ohms wire impedance to 50 Ohm 
coax). I use n1=3T/n2=12T tapped @6T transformer (2m high, 20cm wide with 0.8mm 
wire)

What can be the reason for the impedance transformation is rather off to the 
calculated value?

This is the T2 transformer from 2019:
http://ha3ln.hu/VNA_190116_230811.jpg
...and this from yesterday:
http://ha3ln.hu/VNA_210101_153241.jpg

I have
- same wire with the diam (even from the same roll)
- same BN73-202 cores (tried to use several cores from different
   sources to eliminate the possible mix inconsistencies)
- same winding method (including n2 tapping)
- created a low inductance test resistor network for 744 Ohms

...tried to wind
- lousy, and precise (crossing windings vs. side-by-side, bunched
   wires, etc.)
- n1 first and n2, after n2 first and n1, of course no difference.
- without the tapping, same as above.
- difference turning ratios (3/12, 2/12, 1/12, 3/11, etc.) to see
   the change


The best I could reach now on 160m is
- SWR: 1:1.29 (Rs=40.4 Ohms, Xs=-5.4 Ohms) vs. in 2019:
- SWR: 1:1.16 (Rs=43.2 Ohms, Xs=-1.6 Ohms)

I know, Beverages are really die hard antennas and this increased mismatch 
might have zero effect on performance but still, the engineer part of me...

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: (2wire) Beverage transformers

[Lee STRAHAN]

Hello Csaba,
   I approach this problem this way your impedance ratio is 745/50 ohms or 14.9 
. To get turns ratio use the square root of that which is 3.86 . So round that 
up to 4 as a good turns ratio.
  On a BN73-202 core I usually use a minimum of 4 turns on the 50 ohm side for 
160 meters, so the secondary would need 4 turns ratio times that for 16 turns. 
Therefore 16 turns tapped at 4 turns should work for you. Some will say the 3 
turns on the 50 ohm side should work and the secondary then would be turns 
ratio 4 times that or 12 turns. Therefore 12 turns tapped at 3 turns should 
work well also. Sorry, I do not follow your formula as shown but you can use 
the above and it will work fine as an 800 ohm load to the 745 ohm source. This 
will reflect 745/16 or 46.6 ohms to your cable. SWR for that at the 50 ohm 
cable  is 50/46.6 or 1.07 using resistance only for evaluation. 
Lee   K7TJR  OR

-Original Message-
From: Topband  On Behalf Of HA3LN
Sent: Saturday, January 2, 2021 4:59 AM
To: topband@contesting.com
Subject: Topband: (2wire) Beverage transformers

Hi All and HNY for 2021.

Preparing for the CQ160m with new (2 coax) 2-wire beverages to cover the 
missing azimuthal gaps based on LBDX. The first 2x Bevs worked great back in 
last Jan.

Now I have difficulties with reaching good imped match with the
T2 transformer (responsible to transform the 745 Ohms wire impedance to 50 Ohm 
coax). I use n1=3T/n2=12T tapped @6T transformer (2m high, 20cm wide with 0.8mm 
wire)

What can be the reason for the impedance transformation is rather off to the 
calculated value?

This is the T2 transformer from 2019:
http://ha3ln.hu/VNA_190116_230811.jpg
...and this from yesterday:
http://ha3ln.hu/VNA_210101_153241.jpg

I have
- same wire with the diam (even from the same roll)
- same BN73-202 cores (tried to use several cores from different
   sources to eliminate the possible mix inconsistencies)
- same winding method (including n2 tapping)
- created a low inductance test resistor network for 744 Ohms

...tried to wind
- lousy, and precise (crossing windings vs. side-by-side, bunched
   wires, etc.)
- n1 first and n2, after n2 first and n1, of course no difference.
- without the tapping, same as above.
- difference turning ratios (3/12, 2/12, 1/12, 3/11, etc.) to see
   the change


The best I could reach now on 160m is
- SWR: 1:1.29 (Rs=40.4 Ohms, Xs=-5.4 Ohms) vs. in 2019:
- SWR: 1:1.16 (Rs=43.2 Ohms, Xs=-1.6 Ohms)

I know, Beverages are really die hard antennas and this increased mismatch 
might have zero effect on performance but still, the engineer part of me...


Thanks for the responses.


73!
Csaba  HA3LN
http://ha3ln.hu/
_
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_
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Re: Topband: (2wire) Beverage transformers

[Lee STRAHAN]

Sorry Guys, I miss interpreted Csaba’s transformer problem. My email program 
truncated the URL’s and most of the information past that point. What I did get 
I misread as a result so now I am curious also of his dilemma.
Lee   K7TJR OR

From: Don Kirk 
Sent: Saturday, January 2, 2021 3:03 PM
To: Lee STRAHAN 
Cc: HA3LN ; Mike Waters 
Subject: Re: Topband: (2wire) Beverage transformers

Hi Lee,

I don’t think he needed any tools (formulas, etc.), he is just trying to figure 
out why his recently made transformer does match closer to one he made a year 
ago.  He too agrees that the SWR with his new transformer is likely not an 
issue, he is just trying to figure out why his new transformer is different 
than his previous one, and that’s why I measured one of my own so he had 
another data point to work with.

His transformer from a year ago was 1.16 to 1 whereas his new transformer 
measured 1.29 to 1 and that’s bugging him from an obsessive standpoint.

The reason I mentioned 2 windings was because of how you responded to Mikes 
question.  I'm really not familiar with reversible beverages and jumping into 
this topic helped me learn a bit about them (I love learning).

Just FYI, and Happy New Year to you and yours too.
Don (wd8dsb)



On Sat, Jan 2, 2021 at 5:15 PM Lee STRAHAN 
mailto:k7...@msn.com>> wrote:
Hi Don,
Regardless of the transformer whether it’s a tapped or separate. I gave him 
the tools that should make whatever he does correct. Personally I keep my 
Beverage when I make one at 450 ohms which makes the matching much easier for 
me. I just put up my first one yesterday in several years to test a new 
brainstorm antenna.
   From what I saw he had a 1:1.16 SWR which could not get much better in my 
opinion. Apparently he thought it could be better.
All is good  HNY
Lee  K7TJR  OR


From: Don Kirk mailto:wd8...@gmail.com>>
Sent: Saturday, January 2, 2021 1:54 PM
To: Lee STRAHAN mailto:k7...@msn.com>>
Cc: HA3LN mailto:l...@ha3ln.hu>>; Mike Waters 
mailto:mikew...@gmail.com>>; topband 
mailto:topband@contesting.com>>
Subject: Re: Topband: (2wire) Beverage transformers

Hi Lee,

Csaba also refers to this transformer as T2 and based on what he has said so 
far I suspect he is constructing something similar to the two direction 
beverage shown in figure 7-115 in the 5th edition of Low-Band DXing.  And T2 is 
indeed a two winding transformer with center tap.  This transformer transforms 
the impedance of the open wire transmission line (745 ohms in Csabas case) to 
the coaxial feedline (75 or 50 ohm).  The center tap is used to feed another 
transformer (T1).

I could be wrong but reading between the lines I probably am correct.

Just FYI,
Don (wd8dsb)

On Sat, Jan 2, 2021 at 4:09 PM Don Kirk 
mailto:wd8...@gmail.com>> wrote:
Hi Lee,

Csaba said his transformer was  " n1=3T/n2=12T tapped @6T ".  This sure sounds 
like a transformer with two separate windings (3 Turns on the Primary, and 12 
Turns on the Secondary and then it also has a center tap on the secondary), but 
I could be wrong.  I think Csaba needs to clarify exactly what his transformer 
is, and his test circuit.

Don (wd8dsb)

On Sat, Jan 2, 2021 at 3:22 PM Lee STRAHAN 
mailto:k7...@msn.com>> wrote:
Hi Mike,
   Assuming that you did not miss that this was a tapped winding and not 
separate windings as Csaba mentioned. I see on reflection that he measured 
1:1.16 on one of his tests. In reality it wont likely get much better than 
that. That test was likely the 3:12 he mentioned using. The high impedance side 
of these transformers are a little unpredictable using simple formulas with 
winding capacitance and magnetizing inductance added in the mix.
  Sometimes I use wire wrap wire if it is not going to be used outside 
otherwise I use #27 high temp motor winding class insulation wire which helps 
keep from shorting the wires to the core. I have the benefit of many part 
spools of motor winding wire scraps from a best friend and Ham in the Motor 
rewinding business. By the way, Norton amplifiers require 1:11:4 which is the 
same problem to solve as they are separate windings in the ones I use. I also 
fit shrink tubing in the Norton amp cores for insulation first. I don’t use 
Teflon because it has a dielectric constant around 5 which increases the 
capacitance from the wire to the core. Its tedious but can be done easily. And 
in the case of the Norton amp it leaves room for a larger wire on the 1 turn 
winding. Yes 4 AND16 for 20 total can be done but yes it takes time and lots of 
patience. For those turns counts I go to # 75 material toroid cores which have 
slightly more winding room but require more turns usually for 160 meter stuff.  
All this probably more than you wanted to know. HNY
Lee  K7TJR  OR

From: Mike Waters mailto:mikew...@gmail.com>>
Sent: Saturday, January 2, 2021 11:44 AM
To: Lee K7TJR mailto:k7...@msn.com>>
Cc: HA3LN mailto:l...@ha3ln.hu>

Re: Topband: Important Alert

[Lee STRAHAN]

  I looked at the headers in that email and one IP address was reported as a 
shop in Fremont Ca. The other IP addresses in the email did not report any 
information except the lookup was denied due to excessive lookups of the IP 
address. 
  So for now I still treat that email as very suspicious.
Lee  K7TJR   OR


-Original Message-
From: Topband  On Behalf Of W7TMT 
- Patrick
Sent: Thursday, January 28, 2021 10:55 AM
To: fmoeves ; topband@contesting.com
Subject: Re: Topband: Important Alert

That is the right question!


From: Topband  on behalf of 
fmoeves 
Sent: Thursday, January 28, 2021 10:53:51 AM
To: topband@contesting.com 
Subject: Re: Topband: Important Alert

Is this a scam?Sorry I get many scams in the past year. Fred KB4QZH
 Original message From: Admin  Date: 1/28/21  
1:50 PM  (GMT-05:00) To: topband@contesting.com Subject: Topband: Important 
Alert You have received an important message.Due to new covid19 
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Re: Topband: The Magic-T

[Lee STRAHAN]

Hi Low Band people,
   Nice presentation Steve. I would like to point out that Beverage users or 
even other phased antenna users should not use paralleling two 75 ohm coaxes 
and then matching them back to 75 for the receiver. While on the surface that 
all sounds good there is a little problem for the individual antennas. If you 
look from the wire through the Beverage transformer to the parallel junction 
the antenna transformer actually sees the other antenna at 75 ohms in parallel 
with the rig matching transformers 75 ohms. This causes the real load impedance 
on the Beverage transformer to be 37.5 ohms and not 75. This may cause the 
Beverage to not have the anticipated impedance flat curve or possible 
performance problems. This could also make the end load resistor not be an 
anticipated value. If you use a delay line in one antenna for stagger, the 
following should be noted. It has been my experience that although 
theoretically you only need to match at least one end of a coax for the phase 
delay in circuit to match the proper terminated value, I have found that 
terminating both ends reduces problems from component tolerances not 
terminating the proper coax impedance causing unwanted phase shifts. Using a 
Magic Tee will help terminating the coaxes with their proper impedance keeping 
the phase delay where you expect it.  Early designers of passive 4 or more 
element receiving arrays missed this point when making combiners for arrays 
using paralleled transmission lines. 
   Bottom line is to yes yes, use a Magic Tee or some version of a hybrid 
combiner for combining which will isolate between  antennas.. Then the antennas 
as well as the receiver will see the 75 ohm load as likely designed.
 Here is a nice technical tutorial on the Magic Tee. 
https://michaelgellis.tripod.com/magict.html 
Lee  K7TJR  OR

-Original Message-
From: Topband  On Behalf Of 
donov...@erols.com
Sent: Tuesday, February 9, 2021 3:28 PM
To: topband 
Subject: Re: Topband: The Magic-T


This is the corrected URL for Steve's Magic-T video 


www.youtube.com/watch?v=_Bbt1IcC4bk 


73 
Frank 
W3LPL 
- Original Message -

From: "VE6WZ_Steve"  
To: "topband"  
Sent: Tuesday, February 9, 2021 10:29:54 PM 
Subject: Topband: The Magic-T 

Today I uploaded a video to my RX series which explains the Magic-T combiner. 
I have received a few emails asking me “how do I make the magic-T”? so I 
thought a video would be helpful. 

I show the method for winding and building the Magic-T combiner and I explain 
how it is used in phased RX antennas. 
The associated 2:1 impedance transformer is discussed, and I show the 
difference between an isolated and auto-transformer architecture. 

I also discuss an error that can be made when building phased RX antennas if 
care is not taken to avoid an unintentional 180 phase shift at one of the 
elements, especially if using home-brew matching boxes. 

YouTube video: https://youtu.be/_Bbt1IcC4b - 

73, de steve ve6wz 
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Re: Topband: The "Magic-T" vs 0 degree and 180 degree hybrid combiner/splitters

[Lee STRAHAN]

Hi All,
Rick I have to agree with you up to a point. Your 9 circle and other 8 
circle receiving arrays except mine are on wide footprints and only use 4 
active antennas at a time. All of my antennas are reduced footprint antenna 
arrays which require much more phasing accuracy for optimum performance. In a 
small array such as a 4-square there is a need for at least 2 combining 
channels before a final combination. Many more in the all active 8 element 
array. Some with delay lines and some without. If you accurately measure a 
Magic Tee or an inverting transformer or even a 2:1 impedance matching 
transformer at 160 meters you will find that each one of these has a finite 
degree or 2 of phase shift. Fortunately this phase shift closely scales with 
frequency. I have not tried to fully understand why except they do indeed have 
line length. What is important is I have learned to use various combinations of 
the Magic Tee and the matching transformers, or inverters to my advantage in 
balancing the
  intrinsic phase shift between the inputs and delay lines improving the 
accuracy of the phasing over a broad range of frequencies. Sometimes the 
transformers are introduced into a phasing channel where one is not necessarily 
needed just to balance the phasing. Past conventional thinking about antennas 
was that if you could get 20 dB of front to back ratio on any array you were 
doing good. In my arrays with lots of front to back ratio (not all models)  
this attention to detail of phasing almost always produces 30 dB of front to 
back ratio and when combined with new version more accurate element amplifiers 
I am getting reports of 40 dB front to back 
 So sometimes what looks unneeded and out of place may not be just because it 
looks out of place.
  Lee  K7TJR  OR



I often see 8 circle phasing networks that use a 3 piece ensemble of separate 
magnetic parts, consisting of:

1.  A 1:1 transformer wired for a 180 degree phase shift 2.  A 0 degree hybrid 
("magic-tee"), and 3.  A 37.5 ohm to 75 ohm transformer.

A single 180 degree hybrid replaces all 3 of the above.
(There is nothing "incorrect" about the 3 piece ensemble; it's just needlessly 
complicated).

My 9 circle array uses this very successfully.

73
Rick N6RK
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Topband: FW: The WD8DSB mini-flag antenna (LONG!)

[Lee STRAHAN]

Hi John,
   What did you use as the P3 bandwidth for your noise measurement?  And 
conversion to 1Hz equivalent.
 The P3 has its own bandwidth and is not affected by setting the receiver 
bandwidth.
Lee  K7TJR OR

(Note:  what follows is a long, technical discussion about noise and “small” 
antennas.  I invoke some math and physics here, so if you are not comfortable 
with it, feel free to disregard or delete this e-mail.  I went through this 
exercise to help teach myself the limits here and maybe others might find it 
helpful or educational as well.)

  
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