[Elecraft] OT- Radials for Vertical Antenna

[Barry LaZar]

Mike,
     Tuned radials are really not needed in an elevated radial setup. 
You just put an ATU at the base of the vertical section and run 2-4 
radials from the ground of the ATU. The only issue is making sure the 
antenna system is really high enough to be called raised. I would shoot 
for elevations in excess of 1/10 wavelength, and preferably a bit more.  
Impedance of the antenna is totally unimportant as the ATU takes care of 
making sure your transmitter "sees" a proper load.

73,
Barry
K3NDM

On 7/1/2013 12:49 PM, Mike WA8BXN wrote:
> Randy,
>   
> I think elevated radials need to be tuned, that is a particular length for a
> given band. If you will be operating multiple bands, a set is needed for
> each band. Radials on or under ground do not need to be a particular length
> to work (more and longer is probably always good).
>   
> What band(s) do you want to operate? If 20 meters, you might consider an end
> fed half wave vertical that would not need much ground system.
>   
> 73 - Mike WA8BXN
>   
>   
> -------Original Message-------
>   
> From: Randy Cook
> Date: 07/01/13 12:30:28
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] OT- Radials for Vertical Antenna
>   
> I would appreciate any help from the group on my unusual antenna situation.
> Not really Elecraft related, so OK to respond off line.
>   
> Recently, we had to gut our back yard, as several Redwood trees were
> undermining a retaining wall. Bad situation. So, the trees had to go, and
> with them my antenna supports! I now have essentially a 50ft by 30ft yard
> with 6ft fences on the three sides, house and porch on the fourth. Some
> hardscape prevents long radials. For aesthetic reasons, I don't have a tower
> or tall supports. My first shot was a fiberglass pole, at about 34ft, with a
> wire up the middle. Terminates in the base to an MFJ antenna autotuner. I
> placed the pole a few feet from the corner of the lot where, when painted,
> blends into a neighbors tree behind, and is an barely visible from the
> street.
>   
> My limitations are the radial field. I did some research, and started with 8
> wires, varying from 15' to 35' in a 100 degree spread on the flower beds and
> small lawn. Another ham suggested elevated radials as an alternative, so I
> tried two 35' radials at 90 deg angles along two fence sides, about 4' off
> the ground. Much of what I read was from hams with big lots and dozens of
> radial in all directions. Couldn't find much on my situation.
>   
> Conditions have not been that good, and other commitments have prevented
> much testing. I have some time now and want to find the best solution.
> Questions for the group--
>   
> Give the limits on the radial field (90-110 degrees, limited length) is 10
> buried better than 2 elevated?
>   
> Does it make sense to use BOTH elevated and buried?
>   
> Some prelim testing, using some SE Asia DX stations, showed little
> difference in the receive signal strength switching in either or both radial
> plans. I plan on using some on air events this week to gather signal
> strength reports on my transmissions.
>   
> Any thoughts?
>   
>   
> 73
>   
> Randy Cook - K6CRC
> K3 #2051
> k6crcus at gmail.com
>   
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