[Elecraft] OT: Elevated vs. Buried Radials

Sun May 19 17:14:18 EDT 2013

An oft overlooked advantage to elevated radials is that, properly 
terminated, they will keep your hat from blowing off.
________________________________
John T. Gwin
jtgwin at comcast.net
JudgeJohnGwin at WilsonCountyTN.com
----- Original Message ----- 
From: "Ralf Wilhelm" <ralf at super-deutschland.net>
Cc: "elecraft List" <elecraft at mailman.qth.net>
Sent: Sunday, May 19, 2013 3:59 PM
Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials


> My today's experience was that my nice KX3/ATU which happily tuned my 
> random wire when running from a power supply two weeks ago refused to load 
> the same wire at the same location on all bands below 10 megs when running 
> from the internal battery. However, I could convince it to tune the 
> antenna while I was touching the case of the transceiver (I have been 
> doing some simulations In order to gain some understanding why the german 
> "Multiband-Fuchskreis" sold by a german Elecraft reseller seems to work in 
> some situations and doesn't work for others and just used what I learned 
> from my simulations)
>
> Obviously the "counterpoise" was missing (or in my words the capacitance 
> of the case to ground was not high enough). I could not test if plugging 
> the headphones in and using them is sufficient to increase the capacitance 
> sufficiently ;-)
>
> So, although not directly related to elevated radials, this former OT post 
> has a relation to Elecraft equipment now ;-)
>
> BTW, is there any idea concerning the order of magnitude of the 
> capacitance of a human body (6ft tall, normal weight) with respect to 
> ground?
>
> Vy 73, Ralf, DL6OAP
>
> Am 19.05.2013 um 17:28 schrieb Walter Underwood <wunder at wunderwood.org>:
>
>> A vertical dipole can be balanced with the lower element shorter. It will 
>> have more capacitance to ground, which makes it electrically longer. This 
>> is like putting a capacitance hat on the end of an element.
>>
>> wunder
>> K6WRU
>>
>> On May 18, 2013, at 11:36 PM, Oliver Johns wrote:
>>
>>> ELEVATED RADIALS:  I think Joe hits it on the head here.  A vertical 
>>> with elevated "radials" is essentially an OCF dipole.  There is no 
>>> particular reason for the "radials" to be a quarter wavelength.  They 
>>> should be whatever length lets you resonate the antenna with a feed 
>>> impedance you can live with.
>>>
>>> IMPT POINT:  If you want your antenna actually to have a vertical 
>>> radiation pattern (low angle, omni-directional) then the elevated 
>>> radials must be symmetric.  If there are two, they must be of exactly 
>>> equal length and point in exactly opposite directions.  If there are 
>>> four, they must be equal and point in directions 90 degrees from one 
>>> another. This symmetry guarantees that the "radials" do not radiate. 
>>> The do carry currents, they do help resonate the antenna, but if they 
>>> are symmetric radiation from them cancels and they therefore do not 
>>> radiate appreciably.
>>>
>>> 73,
>>>
>>> Oliver
>>> W6ODJ
>>>
>>>
>>> On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <lists at subich.com> 
>>> wrote:
>>>
>>>>
>>>>> Personally, I do wonder about the new fangled "no radials required"
>>>>> antennas. But, I have an old R5 and it works well.
>>>>
>>>> The "no radials" antennas are basically a vertical OCF - the short
>>>> decoupling radials are the short leg and the vertical is adjusted
>>>> through the use of traps, stubs and/or loading to resonate on the
>>>> desired band with the fixed length (typically 42") of the short
>>>> "radials".
>>>>
>>>> 73,
>>>>
>>>> ... Joe, W4TV
>>>>
>>>>
>>>> On 5/18/2013 9:25 AM, Bill wrote:
>>>>> The cleanest installation is to put the radials in the ground - but, 
>>>>> not
>>>>> portable at all. The idea is a capacitance connection with the earth. 
>>>>> I
>>>>> have used welded steel cattle fence in the past - I build a mat that 
>>>>> is
>>>>> about 30 or 40 feet out from the base of the antenna.
>>>>>
>>>>> For raised radials - they must be resonate to function properly. Three
>>>>> or four per band or related band. They have to be high enough that 
>>>>> they
>>>>> present no danger to anyone roaming around your antenna field. They 
>>>>> can
>>>>> be drooping or horizontal - both work well.
>>>>>
>>>>> Personally, I do wonder about the new fangled "no radials required"
>>>>> antennas. But, I have an old R5 and it works well. Perhaps the way to 
>>>>> go
>>>>> is a new antenna that just gets bolted to a post and a feedline
>>>>> attached. Sure makes life easier and from folks I talk to all the 
>>>>> time -
>>>>> they do work. Forget that they are a little expensive. You buy an
>>>>> antenna to use for years.
>>>>>
>>>>> Read the eHam reviews and see what other users are saying before you 
>>>>> buy
>>>>> anything. Ask on the air.
>>>>>
>>>>> The best I ever had was a Butternut of some kind over a bunch of 
>>>>> buried
>>>>> fence. Might still be the way to go. But, if I was doing it now, I'd 
>>>>> be
>>>>> looking at a "no radials required" antenna. My reasoning is somewhat 
>>>>> age
>>>>> related.
>>>>>
>>>>> Be looking forward to the sage advice that will come from this post. 
>>>>> It
>>>>> is summer - so it is antenna time.
>>>>>
>>>>> Bill W2BLC
>>>>> ______________________________________________________________
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>>>>>
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>>>
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>>
>> --
>> Walter Underwood
>> wunder at wunderwood.org
>>
>>
>>
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