All comment appreciated & thanks! I tried to put together everyone's good
ideas and just finished etching a prototype board about an hour ago  sure
takes longer for the 3oz material.
The boards are for three sets of homebrew stack matches so there are 50 ohm
traces and 22 ohm traces. The relays are the TE/Shrack RT1 style so a bit
of a compromise/challenge to get the trace spacings to work out.
Using the online calculator that Jim linked me to, I ended up settling on
150 mil wide traces for the 50 ohm circuits and 300 mils for the 22 ohm
circuit based on 11A RMS and 15.5A RMS respectively. This should keep me at
about 25C max rise. For isolation I maintained at least 176 mils and 124
mils respectively for the 50 ohm and 22 ohm based on ~800900V and ~550600V
PEP. I will tin the traces and use a conformal coatings as well for extra
insulation per your recommendations.
Rick and Steve's comments about the position w.r.t. standing waves is
certainly applicable since the boxes will be mounted midway between antennas
 but with VF should be able to shoot for 1/2 wave multiples electrically
away from the feed points.
2.25:1 unun's are W2FMI trifillar style wound on FT240K's with homemade 22
ohm coax. I used the 4 layers of Scotch 92 wound on 14AWG thermalize recipe
with a tightly wrapped 1/8 outer braid.
I will test the boxes into a pair of dummy loads before installing them and
see what kind of heating I end up with...
Thanks again!
Matt
KM5VI
Original Message
From: TowerTalk [mailto:towertalkbounces@contesting.com] On Behalf Of Steve
Hunt
Sent: Sunday, August 03, 2014 3:33 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Circuit Board Question
On a mismatched line  whatever the load impedance  the voltage and current
maxima are a quarterwave apart.
Steve G3TXQ
On 03/08/2014 00:07, Richard (Rick) Karlquist wrote:
>
>
> If the load impedance is resistive, whether 50 ohms or not, the
> voltage and current maxima will occur at the same places.
>
> Rick N6RK
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