The r-f loss at the operating frequency in a set of buried radials varies
with the conductivity and permittivity of the earth in which they are
buried.
The NEC4.2 study below shows that for poor earth conditions (within about
1/2WL from the base of the monopole), the number and length of
That's a lot of good information, Richard! Thanks for sharing!
73,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Richard
Fry
Sent: Friday, February 14, 2014 7:00 AM
To: topband@contesting.com
Subject: Re: Topband: Question - optimum
On 02/14/2014 09:15 AM, Charlie Cunningham wrote:
That's a lot of good information, Richard! Thanks for sharing!
73,
Charlie, K4OTV
The whole topic of radials as it applies to me on my small lot is put
in as many as you can. The same probably applies to others on small
lots. On top band I
Besides optimim number(s), I wonder if there is supporting analysis for the
connection of the radial ends??
I have around 80 elevated radials that range from 50 foot lengths, running east
and west, and 25 foot lengths running north and south (all of that a function
of being geographically
While Tom touched on the subject yesterday the subject of an individuals
ground conductivity has to be stressed, continuously it seems. The FCC maps
arent perfect and hams usually dont have the options of perfect siting for
their verticals as do many of the BC stations.
Home developers often
Hi, Bill
Well, like you, I also live on a fairly small city lot with way too much
bedrock coming up to the surface and a long concrete driveway, so buried
radials just aren't feasible for me! So I hung my inverted L in a tall tulip
poplar in one corner of the lot and I ran two elevated resonant
Yeah, just a few elevated resonant radials can work wonders as you have
discovered, Carl! And rock does get in the way of buried radials!! The
models teach that elevated resonant radials should work very well!
73,
Charlie, K4OTV
-Original Message-
From: Topband
I would expect it to work OK with 75 ohm cable. An open-circuited 1/4 wave
line looks like a short at its sending end and you would be looking for a
null as the line reaches a 1/4 wavelength, so I would expect the method to
work fine with 75 ohm line. In fact, the 50 or 75 ohm line, if we
I used a noise bridge to cut all the RG-11 stacked yagi and phased verticals
phasing lines as well as harmonic stubs here when running a 2 station single
op contest, before SO2R.
Using the station receiver also works well as the backround noise null is
easily heard. I did that several times
Hello,brethren-in-low-bands,
Anyone who has had experience with EWE antennas please share the wealth of your
knowledge:
1. How critical are the physical parameters of the aerial, e.g. if I go 3
meters high and 13 meters long?
2. Any suggestions on the change impedance with the change of
Null depth is a function of cable loss.
Heliax produces the deepest null, small diameter coax (RG-59, RG-58) is quite
poor
75 vs. 50 ohm should make no difference.
73
Frank
W3LPL
- Original Message -
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To:
Has anyone heard or worked these guys on 80 or 160?
73, Jim K9YC
_
Topband Reflector Archives - http://www.contesting.com/_topband
Jim,
N6SS in AZ worked him a few days ago at our SS on 80m. They were on 80m
RTTY yesterday at SS and workable in AZ. I don't do RTTY, so still looking
for them,
They were also on yesterday at SS on 160m but no one west of W5 land heard
or worked them.
Its going to be difficult with the Contest
They have been on 160/80 almost every day, so far I have not heard
a peep on 160, seems they are on for their sunset and then move
to 80. Right now at 1700Z they are 579 at my sunrise peak on 3510
Think they start on 160 about 1400-1430Z
73 Merv K9FD/KH6
Has anyone heard or worked these
In reference to all the ground radial postings;
A link to a source of RF ground radial links, all in one place without
having to search the web, links are always updated.
-73-
http://www.rossradio.net/
+
Today's Topics:
1. Re: TO7CC
- Original Message -
From: donov...@starpower.net
To: topband@contesting.com
Sent: Friday, February 14, 2014 11:42 AM
Subject: Re: Topband: Palomar R-X Noise Bridge
Null depth is a function of cable loss.
** Yup
Heliax produces the deepest null, small diameter coax (RG-59,
Heard bits and dits on 160 last night my sunset gray line, but noise from
snow was too great for solid copy. Worked them at 0100 on 80 on Wednesday.
Not strong, but workable. They have said that they will operate through
their night if there is an opening on 80 and/or 160.
73,
Ken - K4XL
On
On 2/14/2014 11:04 AM, Kenneth Grimm wrote:
They have said that they will operate through
their night if there is an opening on 80 and/or 160.
They need to understand grey line propagation to work NA on 160 and 80,
and to realize that there's an opening to Zone 3/4 around their sunset
and
Jim,
Your points about understanding grey line propagation is right. I know
that they have been on almost everyday working just that. If you have a
great circle map located on your QTH you will see a very great difference
in paths between FT5ZM and TO7CC. FT5ZM was almost a East West path and
On 2/14/2014 10:55 AM, Carl wrote:
The highest VF and lowest loss produces the deepest null but also the
least deep null bandwidth due to the higher Q.
Not always -- stubs made with higher Vf cables are longer, so in my
experience they come out about the same for attenuation and bandwidth.
Makes sense. The lower the return-loss, the deeper the null!
73,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
Sent: Friday, February 14, 2014 4:17 PM
To: topband@contesting.com
Subject: Re: Topband: Palomar R-X Noise
- Original Message -
From: Jim Brown j...@audiosystemsgroup.com
To: topband@contesting.com
Sent: Friday, February 14, 2014 4:16 PM
Subject: Re: Topband: Palomar R-X Noise Bridge
On 2/14/2014 10:55 AM, Carl wrote:
The highest VF and lowest loss produces the deepest null but also the
List
Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex
Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of
resonance point on the tower. To refresh everyone's memory here are the
specifics:
90' Skyneedle that is 12 round at the base and 4
Sorry Carl, I hit the send button before responding..Now.
I believe that first #14 wire is a bit small.
I do not believe that you will find a 50ohmZ and X=0 point.
I have 80ft of Rohn 45G with a Telrex 20M546 at 80ft, 3el on 15 at 90 and 3el
on 10 at 100ft. I shunt feed the tower for 160
with
Is the single 14AWG too thin causing goofy readings?
Absolutely! Treating the Sky Needle and the #12 wire as a folded
dipole and using 8 for the diameter of the tower, you have a 16:1
step-up with the single #14 wire.
If you made a cage of 4 or 6 wires with a 6 to 8 diameter, back of
the
Thanks Dean
The one I'm looking at is the old heathkit with the various coil plug ins. The
kit comes with a coil that goes down to 1.600.
Is there another one you can recommend that may go down further? ON4UN says my
tower should be close to 115 degrees others say closer to 140 degrees
There seems to be some confusion, Carl!
First of all, since the gamma match (regardless of the diameter of the gamma
rod) is a shorted transmission line, less than 1/4 wavelength it WILL have
series inductive reactance that you will need to tune out with a series
variable capacitance.
Second, I
Hi Carl,
It sounds like you are trying to find 50 ohms on the tower without any
series capacitor by looking at R and X. I would not try to do that. The
reactance puts you out of range on the MFJ bridge. You are down to a few
bits difference between data points the PIC needs in the MFJ.
Well, of course not, Tom! I need to be more precise and keep in mind the
audience on this Reflector, and that you are always lurking out there in the
weeds to chide and chastise me! Of course devices that are pure real over the
frequency range of interest would not be resonant! I guess I was
On 2/14/2014 2:17 PM, Carl wrote:
Isnt that what lowest loss means? At least that was my intention.
I must not have written clearly enough. I was not questioning the low
loss, only that the high Vf was the way to get it.
You DO get the low loss by going to larger coax, (like the 7/8-in hard
All generally true, I expect, but I also believe that dielectric constant
and dielectric losses also figure in and the lowest loss lines would be
filled with air, dry nitrogen or evacuated. I expect those would likely be
the lowest loss AND highest velocity factor cases.
73,
Charlie, K4OTV
By the way, Carl, you indicated that whe you were tapped at 90', the real
part was 60 ohms when you tuned ou't the series reactance with th;e series
capacitor!!
Gee!! That ain't a bad match!! Should result in about 1.2:1 VSWR when fed
with 50 ohm cable!! Not bad at all and certainly not enough
Tom and all
Thanks for the responses.
I was under the assumption that I would find a 50 ohm tap on the tower but with
a lot of reactance requiring a cap that would tune out the X but leave the 50
ohm resistive value in place.
I knew my tap was too low at 46' when I saw less than 50 ohms
On 2/14/2014 7:00 PM, Charlie Cunningham wrote:
All generally true, I expect, but I also believe that dielectric constant
and dielectric losses also figure in and the lowest loss lines would be
filled with air, dry nitrogen or evacuated. I expect those would likely be
the lowest loss AND highest
Well, if those 4 discrete tap points are the only ones that you have
available, Carl, you likely won't find one that give that gives you 50 ohms
real. So the best that you can do is pick the one that falls closest to 50
ohms real when you tune out the series inductive reactance with the
Thanks, Jim
Well, I confess that most of my professional work has been near or above 1
GHz
Thanks for tip about the Times datasheets!
73,
Charlie,K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
Sent: Saturday, February 15, 2014
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