[TowerTalk] 80m Folded Counterpoise / 4 square

[John Simmons]

N6BT's vertical on ring design. See:
https://nextgenerationantennas.com/presentations-1


-- 
73,
-de John NI0K in rural Debs, MN USA

Thomas Collins wrote on 3/30/2021 10:27 AM:
> Gentlemen,
>
> This Spring/Summer/Early Fall project is to attempt to erect an 80m wire 4
> square off my tower, but using Folded Counterpoise(s) for each element.  I
> don't have enough property to use elevated radials, and the next door
> neighbor is difficult to deal with.
>
> I'll be using a Comtek box for phasing.  My understanding is that the
> feedpoint of each element needs to be ~ 35 ± 0 ohms for the system to work
> correctly.
>
> I'm not exactly sure what the feedpoint impedance of an FCP with a 1/4
> wavelength element is supposed to be.  I assume from K2AV's article that it
> will be close to 50 ohms.
>
> I do have the isolation transformers for the FCPs.
>
> So, my plan is this:
>
> 1] Erect element #1 with an FCP.
> 2] Use my Zoom 230, a length of coax, and calibrate the Zoom 230 with an
> Open, Short, Load at the end of the test cable.
> 3] Measure the feedpoint impedance.
> 4] Use SimSmith to calculate the matching network to transform the
> impedance of the feedpoint to 35 ± 0 ohms.
>
> Questions/issues:
>
> 1] The isolation transformers are from Balun Designs and are inside the
> typical 4" x 4" x 2" grey PVC box.  My plan is to remove the SO-239
> connector on the box, and add a second grey pvc box "side to side" but with
> the covers 180° from each other.  Then drill holes for the "hot" and ground
> wires from the transformer toroid, so that they can enter the second pvc
> box (keep them separated).  Then use the empty box for the transformation
> network, and connect it to a SO-239 mounted on the box.  Having no idea
> what the impedance is, do you think that would work?
>
> 2] Do I tune the element/FCP to resonance (where the reactance is 0) first
> (~ 3.55 MHz, as per the Comtek manual) THEN measure the impedance, and
> build the network?   Or do I just "get close enough" with the element/FCP,
> then build the network, and then adjust the element for ~ 3.55 MHz?
>
> Or, am I not asking the right question(s)?
>
> Private replies with step by step instructions are welcome!
>
> Thanks!
>
> Tom, N2SR
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk