Cal,
I have used inverted V's and half slopers for the past 40 years on my
towers. I have had mixed results, however most have been successful. On my
Current 50 ft tower I use the top guy wires as half slopers on 12, 40 & 60M.
The major lobe will be in the direction of the sloper from the tower, but
still maintains reasonable omni-directivity.
I placed the guy supports posts out from the tower so the guy wires would be
approximately 45 degree angle to the tower. That angle places the antenna
feed point around 50 ohm impedance. All my guy wires are fed with a single
coax at the top. Insulators are adjusted on the ends to obtain resonance at
the desired frequency. I then also installed insulators at the ground
mounting post. This essentially isolates the unused guy wire without adding
ground capacitance to the active wire.
I have another set of Guy wires midway up the tower and they are also
insulated on both ends so they are floating in the air to reduce any ground
capacitance to the active antenna wires.
I have never modeled an antenna, I just put it up and adjust it until I'm
satisfied with the operation.
Antennas are kind of like the Bumble bee. Aeronautical engineers tell you it
can't fly, but they failed to tell the Bumble Bee.
* 73's Jim W5IFP *
>On Mon, Apr 20, 2009 at 4:27 PM, Cal Zethmayr <w4gmh@cox.net> wrote:
>>
>> I'm working on plans for a 90' tower.
>> Has anyone used the top set of guy wires, with johnnyball
>insulators at the correct places of course to make an inverted
>V, or Sloper?
>>
>>
>> OR..maybe using the guy wires connected at 60' for another
>sloper or Inverted V?
>>
>> And of course using johnnyball insulators on the lower two
>sets of guys to break them up into non-resonant lengths..
>>
>> Ironically I was studying the K1WA sections of the antenna
>handbook this morning and contemplating sending this question
>out to the towertalk panel of experts.
>>
>> Cal Zethmayr
>> W4GMH@cox.net
>>
>> _______________________________________________
>>
>>
>>
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