[TowerTalk] Radial Ends Buried???

Thu Dec 1 12:35:48 EST 2022

We have about 4 foot snow drifts and it's COLD but fortunately the snow is
easy to shovel. hi
Shortly, I plan on erecting the Hi-Gain AV-18HT Vertical and for now ,
laying 10 radials in the snow.
I'm not going to bury the radial ends.
I'm also in the middle of installing two 700 ft beverages 1000 feet from the
shack.
I was hopeful to get all done before snowfall but snow came early this year.
Now I'm shooting for Christmas.
I really appreciate all your comments!  
Dennis - K7OGW

-----Original Message-----
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Sent: Saturday, November 19, 2022 9:00 AM
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Subject: TowerTalk Digest, Vol 239, Issue 25

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Today's Topics:

   1. Re: Radial Ends Buried??? (Jim Brown)
   2. Fwd:  Radial Ends Buried??? (Larry Banks)
   3. Re: Radial Ends Buried??? (Pete Smith N4ZR)
   4. Re: Radial Ends Buried??? (Jim Brown)
   5. Re: Radial Ends Buried??? (Pete Smith N4ZR)
   6. Re: Radial Ends Buried??? (Lux, Jim)

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Message: 1
Date: Fri, 18 Nov 2022 14:10:27 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Radial Ends Buried???
Message-ID:
	<3d94140d-df4a-9dd0-ecb3-efd7d657868c at audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 11/18/2022 1:28 PM, Wes wrote:
> By serendipity, I measured the input impedance of one radial against 
> all of the others and it's resonant at 1.84 MHz.

About ten years ago, I did the experiment of modeling a pair of radials cut
to a free-space resonance,  starting with them as close as NEC2 would allow
it, and raising them in small increments to several feet. VF with that
closest contact was about 0.7. By 3-4 ft, was close to free space, taking
the #14 THHN jacket into account. I also did some measurements of THHN #14
pairs laying on the ground, but don't recall the result.

73, Jim K9YC

------------------------------

Message: 2
Date: Fri, 18 Nov 2022 19:52:58 -0500
From: Larry Banks <larryb.w1dyj at verizon.net>
To: Ham - Tower Talk <towertalk at contesting.com>
Subject: [TowerTalk] Fwd:  Radial Ends Buried???
Message-ID: <7d1672a5-6528-f5b1-6459-a93587ee8775 at verizon.net>
Content-Type: text/plain; charset=UTF-8; format=flowed

The only possible reason I can think of for burying the ends of on-ground
radials is the potential for high voltage at the end.? Just like being sure
that you can't touch the end of a raised radial.

73 -- Larry -- W1DYJ

On 11/18/2022 14:43, Steve Dyer W1SRD via TowerTalk wrote:
> I have a mish-mash of long, short, insulated, bare, solid, stranded, 
> thick, thin, on ground and below ground radials for 80 and 160 that 
> has accumulated over the years.
> It doesn't matter. What matters is how many and length (coverage) with 
> rapidly diminishing returns after 60 or so. Plenty of research to back 
> that number. Make them as long as you can and as symmetrical as you 
> can for the land you have. If you have land to do a beautiful circle 
> of perfectly sized radials, great. Otherwise do the best you can.
> Point being there is no reason for hand wringing over it. Tenths of a 
> dB on the low bands just don't matter.
>
> 73,
> Steve
> W1SRD
>
> On 11/18/2022 10:23 AM, Jim Brown wrote:
>> On 11/18/2022 8:38 AM, Test wrote:
>>> I'm about to install 20 radials for a Hi-Gain AV-18HT and Hi-Gain 
>>> recommends burying the Radial ends if installing less than 60 
>>> radials.
>>
>> There is ZERO reason for radials making electrical contact with the 
>> earth. Their function is to provide return current for the antenna IN 
>> PLACE OF the earth, which is very lossy (that is, it wastes 
>> transmitter power), and to SHIELD the antenna's fields from the earth.
>>
>> 73, Jim K9YC
>>
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
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>
> _______________________________________________
>
>
>
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------------------------------

Message: 3
Date: Fri, 18 Nov 2022 20:15:59 -0500
From: Pete Smith N4ZR <pete.n4zr at gmail.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Radial Ends Buried???
Message-ID: <1d670f1e-985f-5f5a-8bcd-4791e648bc82 at gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

I expect I'm an outlier, in a couple of respects.? I have 30 x 70-foot
radials on the ground under my 160M inverted L.? I'm sure this will bother
people, but I made up the radials from a spool of about a mile of AWG 20,
silver(!)- plated copper wire (military surplus) that I got at Dayton years
ago.? I haven't yet entirely finished the deployment (it's been too darned
cold here) but I'm wondering about the impact of using such small-gauge wire
for this purpose, even with the silver.

73, Pete N4ZR
Check out the new Reverse Beacon Network web server
at<https://reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.

On 11/18/2022 5:10 PM, Jim Brown wrote:
> On 11/18/2022 1:28 PM, Wes wrote:
>> By serendipity, I measured the input impedance of one radial against 
>> all of the others and it's resonant at 1.84 MHz.
>
> About ten years ago, I did the experiment of modeling a pair of 
> radials cut to a free-space resonance,? starting with them as close as
> NEC2 would allow it, and raising them in small increments to several 
> feet. VF with that closest contact was about 0.7. By 3-4 ft, was close 
> to free space, taking the #14 THHN jacket into account. I also did 
> some measurements of THHN #14 pairs laying on the ground, but don't 
> recall the result.
>
> 73, Jim K9YC
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

------------------------------

Message: 4
Date: Fri, 18 Nov 2022 18:21:29 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Radial Ends Buried???
Message-ID:
	<79e98668-c37c-0bf0-ef6e-57943fc6df22 at audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 11/18/2022 5:15 PM, Pete Smith N4ZR wrote:
> I haven't yet entirely finished the deployment (it's been too darned 
> cold here) but I'm wondering about the impact of using such 
> small-gauge wire for this purpose, even with the silver.

The only downside is mechanical -- larger wire may be a bit less subject to
damage.

73, Jim K9YC

------------------------------

Message: 5
Date: Sat, 19 Nov 2022 08:23:32 -0500
From: Pete Smith N4ZR <pete.n4zr at gmail.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Radial Ends Buried???
Message-ID: <1d46a23c-f6da-5301-b9d9-45c68e483d39 at gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

I'm fairly comfortable in that respect - the taxpayers who paid for this
stuff got a darned sturdy product.? It's a battle even to strip.

73, Pete N4ZR
Check out the new Reverse Beacon Network web server
at<https://reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.

On 11/18/2022 9:21 PM, Jim Brown wrote:
> On 11/18/2022 5:15 PM, Pete Smith N4ZR wrote:
>> I haven't yet entirely finished the deployment (it's been too darned 
>> cold here) but I'm wondering about the impact of using such 
>> small-gauge wire for this purpose, even with the silver.
>
> The only downside is mechanical -- larger wire may be a bit less 
> subject to damage.
>
> 73, Jim K9YC
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

------------------------------

Message: 6
Date: Sat, 19 Nov 2022 07:10:37 -0800
From: "Lux, Jim" <jim at luxfamily.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Radial Ends Buried???
Message-ID: <d4e69769-f61e-9d1f-a669-8c50c1f0c931 at luxfamily.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 11/18/22 2:10 PM, Jim Brown wrote:
> On 11/18/2022 1:28 PM, Wes wrote:
>> By serendipity, I measured the input impedance of one radial against 
>> all of the others and it's resonant at 1.84 MHz.
>
> About ten years ago, I did the experiment of modeling a pair of 
> radials cut to a free-space resonance,? starting with them as close as
> NEC2 would allow it, and raising them in small increments to several 
> feet. VF with that closest contact was about 0.7. By 3-4 ft, was close 
> to free space, taking the #14 THHN jacket into account. I also did 
> some measurements of THHN #14 pairs laying on the ground, but don't 
> recall the result.

To a first order, the propagation speed slows as sqrt((1+epsilon)/2) (i.e.
it's like being immersed in a dielectric of half air/half epsilon)

The interesting aspect is that for a dipole (or a wire) on the surface, a
large fraction of the power radiates into the soil, the fraction is epsilon
^(3/2), so with soil with epsilon 15, about 58 times as much power goes into
the soil, as opposed to radiates up in to the air. So radials work a LOT
better on poor rocky soil than on "good wet" soil.

If you want the theory: Rutledge, D. and M. Muha (1982). "Imaging antenna
arrays." IEEE Transactions on Antennas and Propagation 30(4): 
535-540.

------------------------------

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