You've asked this question before in a different form. Check the
archives for the prior thread.
I'll PRESUME the capacitors need to be a different value in the
exterior switch box, but to what?...anyone have a schematic for a
Comtek 4-square? (the outdoor portion)
You will need to change *both* the capacitors and the inductors.
Formulas for both inductors and capacitors are here:
<https://www.researchgate.net/figure/Transmission-line-and-lumped-element-based-a-90-coupler-and-b-phase-delay-cell_fig2_224208944>
The inductors should probably be wound as a bifilar pair on a properly
sized toroid core for the desired power level.
As an alternative, you could replace the lumped circuit with a coaxial
"rat race" as shown in the upper left of that same reference. Since
50/(2)^.5 = 35 Ohms, the two "horizontal" legs can be a pair of 75 Ohm
cables in parallel with only minor impact.
73,
... Joe, W4TV
On 2022-01-22 5:22 PM, Mike Smith VE9AA wrote:
I am trying to go to all 4-squares like my contesting 4-sq buddy John, N8UM
in TN.
I am nearly there, having just installed a 15m one in time for CQWW CW.
There are no new dedicated 10m 4-squares to be found commercially, if my
internet searching skills
are telling me the truth, so recently I bought a 40m 4-Square (Older Comtek,
NOS) and am hoping to mod it for 10m, but I have no idea where to start.
I'll PRESUME the capacitors need to be a different value in the exterior
switch box, but to what?...anyone have a schematic for a Comtek 4-square?
(the outdoor portion)
Apparently Tim, K3LR (DX Engineering) was not happy with the performance
from the 10m Comtek 4-squares, so is not selling them anymore. I can
definitely respect that decision to not produce a top-notch product. I am
not looking to squeeze every fraction of a dB out of a 10m array. I just
want something that 'works', is directional and has some modest amount of
gain.
(I have built several K1WA/K8UR arrays and am not totally happy with them)
My SO2R contest station uses a single horizontal antenna on the 2nd radio
and a bunch of vertical 4-squares on the primary radio.
Any ideas on the Comtek Mod fellas?
Tnx
Mike VE9Antenna Antenna
Mike, Coreen & Corey
Keswick Ridge, NB
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