from:"lee"

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: (2wire) Beverage transformers

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

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

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

Topband: FW: CQWW a bust this year

2020-12-01 Thread 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
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Looking for a 2n5109

2020-10-22 Thread 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

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

Topband: RX Power over Coax

2020-10-06 Thread Lee STRAHAN

 an interesting experiment even if its inconclusive.
   I can modify the new amps for this external power on direct to me special 
request..
73

Lee   K7TJR
Hi-Z Antennas




Subject: Topband: RX Power over Coax

Regarding the issue of voltage over coax to power the preamps used at the base 
of short verticals, Lee, K7TJR, developed an alternative power feed system for 
his new SMD preamps using a separate RG6 coax. Apparently, K3LR is using such 
an approach to avoid sending voltage down the coax in his 8 element HiZ array 
at his contest station.
DXE has begun selling the new version 2 preamps but the description in their 
catalog does not mention this separate power feed system. The older HiZ 
preamps, and the YCCC preamps, can probably be modified to the voltage with a 
separate wire from the combiner box to each vertical antenna preamp.
One question I have with this approach is whether an external power wire would 
also need a common mode choke on it.  Perhaps Lee could offer some opinions on 
this alternative power approach.
73, Dennis W0JXMilan, OH
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Adding connectoirs to CATV Hardline

2020-06-04 Thread lee

Hi Guys,
There is an article in one of the ham magazines from years ago that
describes how to make an adapter from brass tubing compression sleve fittings
(from auto parts store) that adapts from 1/2 inch CATV Hardline cable to UHF
male connectors RG-8 size. Anti-oxidants required. I have been doing this for
years with no problems at 1500 watts. There is a pair on my 80 meter 4-square
as we speak. Its been so long that I have since forgotten where the article
was. Perhaps an internet search would bring it up. I would write something up
but I have my hands full at the moment with cleaning up after a tornado like
storm with 100 MPH winds that went right over my house. Minimal damage except
for the top 1/3 of my 160 vertical and lots of tall trees down in what's left
of the yard. All else is fine with nothing I can't repair.
Good luck.
Lee K7TJR Culver OR

Clamps do work ok with CATV hardline, but you have to be careful as it is very
easy to crush the hardline. Also, waterproofing is always a pain.

As W7WKR posted, I also adapt pin connectors, which are the standard way of
terminating catv hardline. Here are some comments:

Pin connectors have the same thread size (5/8") that is found on so-239s or N
connectors. They are fairly cheap to buy new or can be found on ebay. One
difficulty with pin connectors compared to many other hardline connectors is
that it is nearly impossible to install them on catv hardline unless you have
a coring tool of the right size to fit the hardline. This is because the pin
connectors clamp onto the shield from both sides, so you have to completely
remove the insulation from the hardline for 1-2" back up into the cable. Coring
tools are > $100 new, but I have found them used for $20-$40. The used ones are
often pretty worn out: however, with care you can sharpen the cutting parts
with a file or stone, which makes a big difference. It can also be tricky to
figure out how much center conductor you need sticking out for a given pin
connector- some of the connectors have little tick marks on the outside that
show the correct length to cut the center conductor.

Once you have the pin connector on, then:

1. For type N: the body of a "clamp" type N connector will screw directly onto
the pin connector (discard the smaller clamp part with male threads that
normally goes on the RG-8). I just cut the pin to length and file the end down
to a point. You do have to be careful that the point is not too wide, otherwise
it might break the female contact.

2. For UHF: there are similar clamp-type UHF connectors available with the same
5/8 thread in the connector body. Here is one example:

https://www.w5swl.com/Coax-Connector-UHF-Female-Clamp-fits-RG-8AU-RG-213-Series-Cable--by-W5SWL_p_466.html

just cut the pin to the right length, solder on the center female connector,
and screw the body on.

3. You can also just drill a hole in a metal box and attach the pin connector
with a nut meant to go on SO239s.

There are also splice connectors to join two pieces of hardline. These are nice
because they don't require any waterproofing. There are also some that end in
an F connector instead of a pin.

Tor
N4OGW

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

Re: Topband: Loop on the ground as a counterpoise

2020-05-06 Thread 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




   

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

Re: Topband: Herb

2020-04-30 Thread James Lee

Always sad to learn that a giant in any field has left the battle.  Herb was a 
great positive influence and no doubt a role model for many in our hobby.

James T. Lee, MD
NK7B
Minnesota

> On Apr 30, 2020, at 08:02, topband-requ...@contesting.com wrote:
> 
> Send Topband mailing list submissions to
>   topband@contesting.com
> 
> To subscribe or unsubscribe via the World Wide Web, visit
>   http://lists.contesting.com/mailman/listinfo/topband
> or, via email, send a message with subject or body 'help' to
>   topband-requ...@contesting.com
> 
> You can reach the person managing the list at
>   topband-ow...@contesting.com
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Topband digest..."
> 
> 
> Today's Topics:
> 
>   1. Herbert Schoenbohm, KV4FZ: Silent Key (d...@np2j.com)
>   2. Re: Herbert Schoenbohm, KV4FZ: Silent Key
>  (lennart.michaels...@telia.com)
>   3. Re: Herbert Schoenbohm, KV4FZ: Silent Key
>  (Richard (Rick) Karlquist)
>   4. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Greg - ZL3IX)
>   5. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Jon Zaimes)
>   6. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Jeffrey Embry)
>   7. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Victor A. Kean, Jr.)
>   8. Re: Herbert Schoenbohm, KV4FZ: Silent Key
>  (daraym...@iowatelecom.net)
>   9. Re: Herbert Schoenbohm, KV4FZ: Silent Key (John Harden, D.M.D.)
>  10. Re: Herbert Schoenbohm, KV4FZ: Silent Key (John Harden, D.M.D.)
>  11. KV4FZ (Joe Dube)
>  12. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Nagi)
>  13. Re: Herbert Schoenbohm, KV4FZ: Silent Key (terry burge)
>  14. Re: Herbert Schoenbohm, KV4FZ: Silent Key (jh-...@sbcglobal.net)
>  15. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Eugene Popov /RA0FF/)
>  16. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Chris G3SVL)
>  17. Herbert Schoenbohm, KV4FZ: Silent Key (Ilmo Anttil)
>  18. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Gary Smith)
>  19. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Chris G3SVL)
>  20. Re: KV4FZ (tony@verizon.net)
>  21. Re: Herbert Schoenbohm, KV4FZ: Silent Key (Ed Hughes)
> 
> 
> --
> 
> Message: 1
> Date: Wed, 29 Apr 2020 13:21:13 -0500
> From: d...@np2j.com
> To: topband@contesting.com
> Subject: Topband: Herbert Schoenbohm, KV4FZ: Silent Key
> Message-ID: <0feb6045fa2051112ed5bf6ca2d57...@np2j.com>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
> 
> It is with great regret that I have been informed that Herb Schoenbohm 
> KV4FZ has passed away this morning at his home.
> Herb was 84 years of age.
> 
> Herb has been a fixture on Topband since the very beginning, having 160 
> DXCC #2 (I believe) and has been active in all 160 Meter contests over 
> the years setting many records.
> 
> I personally have been amazed at his stamina in contests, even recently, 
> he would stay up all night CQing long after this 62 year old called it 
> quits...I hope I live as long as Herbie, and be able to put half the 
> rare ones in the log as he did routinely
> 
> 73 Herb
> 
> Best wishes to Herbs wife of over 50 years Monica and Sons Tom, Timmy 
> and Eric
> 
> 
> --
> 
> Message: 2
> Date: Wed, 29 Apr 2020 21:56:19 +0200
> From: 
> To: ,  
> Subject: Re: Topband: Herbert Schoenbohm, KV4FZ: Silent Key
> Message-ID: <000101d61e60$408e4e50$c1aaeaf0$@telia.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Oh, so sad!
> During all my years om 160, my favorite band, Herb has been the man behind
> thosea consistent and loud signals!
> 
> REST IN PEACE dear Herb
> 
> Len Michaelsson
> SM7BIC
> 
> -Ursprungligt meddelande-
> Fr?n: Topband 
> F?r d...@np2j.com
> Skickat: den 29 april 2020 20:21
> Till: topband@contesting.com
> ?mne: Topband: Herbert Schoenbohm, KV4FZ: Silent Key
> 
> It is with great regret that I have been informed that Herb Schoenbohm KV4FZ
> has passed away this morning at his home.
> Herb was 84 years of age.
> 
> Herb has been a fixture on Topband since the very beginning, having 160 DXCC
> #2 (I believe) and has been active in all 160 Meter contests over the years
> setting many records.
> 
> I personally have been amazed at his stamina in contests, even recently, he
> would stay up all night CQing long after this 62 year old called it
> quits...I hope I live as long as Herbie, and be able to put half the rare
> ones in the log as he did routinely
> 
> 73 Herb
> 
> Best wishes to Herbs wife of over 50 years Monica and Sons Tom, Timmy and
> Eric _

Re: Topband: RG-6 Delay cables

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

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

Re: Topband: RG-6 Delay cables

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

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

Re: Topband: RG-6 Delay cables

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

Re: Topband: RG-6 Delay cables

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

 

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

Topband: RG-6 Delay cables

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

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

Re: Topband: Slightly OT - amplifier noise

2020-03-16 Thread 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

Re: Topband: Slightly OT - amplifier noise

2020-03-16 Thread 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  > <mailto:n2ica...@gmail.com>> 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

Re: Topband: Hi Z amplifiers for 160m

2020-03-12 Thread 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

   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

   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 bu

Re: Topband: Hi Z amplifiers for 160m

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

Re: Topband: Hi Z amplifiers for 160m