[SMCARA] Couterpoise Question
Daniel Metcalf
kb3uun at gmail.com
Thu Sep 25 13:44:26 EDT 2014
I have only operated on vertical antennas at my QTH and one thing that I
have just recently done that helped my station out bunches was I buried the
coax (Be sure to use coax that supports direct bury ie. Jefatech LL400
non-flex). Here is the site that I referenced:
http://www.w8ji.com/common-mode_noise.htm here is what was listed in the
summary:
Follow these rules for receiving antennas:
1. With small magnetic loop antennas, make sure the antenna is properly
balanced
2. Lay feedlines directly on earth or bury feedlines in the soil so earth
losses reduce shield current and limit feedline common mode impedance
3. Be sure shield connections are properly made and snug
4. If noise levels are high or antenna sensitivity is very low, isolate the
feedline from the antenna as it approaches the antenna by using choke baluns
5. Ground the feedline a few dozen feet away from the antenna
6. Avoid autotransformers. Instead use isolated primary and secondary
isolated winding transformers
7. Use an independent ground on the antenna. Never connect an antenna signal
ground to the coaxial cable shield!
My current counterpoise involves 7 x 32' radials buried approx. 2" below the
surface. I used an edger to dig the lines for which the radials were laid in
and covered. I use the DX Engineering radial plate and hardware. It really
makes things easy to connect everything up to. Check it out:
http://www.dxengineering.com/parts/dxe-radp-3
Have FUN!
Dan -- KB3UUN
-----Original Message-----
From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Rene
Ramirez
Sent: Thursday, September 25, 2014 10:25 AM
To: Bill Jones
Cc: smcara at mailman.qth.net
Subject: Re: [SMCARA] Couterpoise Question
I go from the tuner into a switch panel..thru conduit out to the side of the
house into a box with my ICE supressors, then into conduit again to cross
the yard underground to the vertical. its all RG-8 and for the past
oh...5 years or so I have yet to have any "RF in the shack" issues". Like
the rest of the guys say. Lay it out, see what it does. If it works make
it permanent. One thing that i consider not an option is surge protection.
so do your research on polyphasors and ICE supressors (im an ICE man). Not
much that the amateur world can offer will protect you from a direct strike
but others will help you to survive the near strikes. But I digress.
On Thu, Sep 25, 2014 at 10:04 AM, Bill Jones <merc669 at gmail.com> wrote:
> Well elevated radials (counterpoise) would not work for me anyways.
> The better-half, dogs and grandkids would disapprove. And different
> reading for long wires are for the counterpoises to complete the other
> half of the circuit, otherwise the coax is used. How much feedback I
> am not sure but would prefer to not have it in the shack. So will try
> and get a few down and hopefully it will be good and I can enjoy
> getting on the air. Once everything else arrives...
>
> Bill
> KC3DEZ
>
> On Thu, Sep 25, 2014 at 9:54 AM, Rene Ramirez <w3bnyren at gmail.com> wrote:
>
>> I once got caught up in the whole counterpoise issue. I have a zero
>> three antenna and I have 60 40' #14 stranded THHN lowes copper wire
>> at dirt level. IF you can elevate them then yes you can do the tuned
>> radials thing (which I might add can be a PITN...literally if you
>> clothes line yourself) but not actually needed. Why 60 radials?
>> thats all the holes my DX engineering mounting plate had. I could
>> have doubled up to 120 radials but I felt it wasnt necessary. Yeah I
>> could have gone and done some modeling etc but I wanted to get on the
>> air. and 60 40' radials is a fair amount of wire to measure, cut,
>> crimp, solder, wash, rinse, repeat! Also, funny thing about elevated
>> radials is you really cant use that area for any kind of recreation, dog
walking etc without disturbing them. bummer...
>>
>> So just get wires down, (there is a method to do this and its almost
>> time to start that will keep your radials and the mower from
>> meeting...ask me offline or separate email on how to do this) and the
>> antenna up and get on the air and see what it does.
>>
>> Ren...
>>
>> On Thu, Sep 25, 2014 at 9:40 AM, Bill Jones <merc669 at gmail.com> wrote:
>>
>>> The End-Fed antenna is the Ultimax DxExtream 77 foot antenna. This I
>>> plan on one end in a tree about 40 feet up and slope it to 10. The
>>> balun itself will also have a 1:1 isolation balun for RF feedback
>>> prevention near the feedpoint and then going into the house. I have
>>> also read that length does not matter for counterpoise and others
>>> that say run a single length for the lowest band and have a few of
>>> these laid. All different opinions...
>>>
>>> Bill
>>> KC3DEZ
>>>
>>> On Thu, Sep 25, 2014 at 9:07 AM, Clarke, Tom AIR4.0P NATOPS <
>>> frederic.clarke at navy.mil> wrote:
>>>
>>> > Bill,
>>> >
>>> > I think the answer is "it depends"! Conventional wisdom has it
>>> > that
>>> the
>>> > length of the radials are not as critical when on the ground or
buried.
>>> > Ground conductivity gets into the act here also. Things would be
>>> > quite different in Arizona!
>>> >
>>> > In your case the 8.6 foot radial is a "tuned" radial and should
>>> > be in
>>> the
>>> > same plane as the antenna, although not critical if it hangs
>>> > vertically (although it may affect the directionality somewhat.
>>> > In the case of
>>> the 80
>>> > meter radial, again it should be elevated to function as a tuned
>>> radial,
>>> > but if your situation calls for it to be on the ground, the
>>> > elevation
>>> of
>>> > the feedpoint should not be added to the radial length, as it is
>>> > all
>>> part
>>> > of the radial length. Since part of the counterpoise is on the
>>> ground, it
>>> > will become detuned by the earth anyway. There are several
>>> > treatises
>>> in
>>> > the ARRL archives concerning grounds, radials, and counterpoises.
>>> >
>>> > FYI, I have a ground mounted vertical antenna and I simply have
>>> > 32, twenty-five foot radials on the ground or slightly buried.
>>> > This works
>>> very
>>> > well. When I had this antenna mounted on a tile roof in EA7 land,
>>> > I
>>> used 4
>>> > elevated, stub-tuned radials which worked very well. Adding
>>> > additional radials on the roof did not make any noticeable difference.
>>> >
>>> > What kind of end fed antenna are you using?
>>> >
>>> > Tom/W4OKW
>>> >
>>> > -----Original Message-----
>>> > From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of
>>> > Bill Jones
>>> > Sent: Thursday, September 25, 2014 6:08 AM
>>> > To: smcara at mailman.qth.net
>>> > Subject: [SMCARA] Couterpoise Question
>>> >
>>> > If I need a 65 to 70 foot counterpoise for 80 Meters and a 8.6
>>> > foot
>>> one for
>>> > 10 Meters and my balun from my end-fed antenna is 10 foot up do I
>>> need to
>>> > add 10 feet to the math to get the counterpoise to ground level
>>> > for it
>>> to
>>> > be effective. In the example of 10 meters the wire is just hanging
>>> > in
>>> air.
>>> > These would be run opposite to the feedline. Thanks!
>>> >
>>> > Bill
>>> > ______________________________________________________________
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>>> > ______________________________________________________________
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>>> >
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>>
>>
>
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