[Milsurplus] TCS Antenna Matching, Again.

[David Stinson]

Good Morning.
I'm de-bugging TCS-13 RX/TX  to prepare them
for trade.  Was discussing this with a friend who
says he's going to "get around to getting mine
on the air."  He said he needed to gather a
bunch of parts to "build a matching box for
the antenna" and/or add turns to the link
output.   We've talked about this before,
but perhaps it is time to take this old horse
out for another ride.

Each to his own, of course.  But if your
goal is to match the output of your TCS
to a 50-ohm, resonant, coax-fed antenna,
you need exactly *one* part per band:
A good-quality, RF capable capacitor
like these 100pFd from Ebay:
https://www.ebay.com/itm/264384761640
https://www.ebay.com/itm/192780283722

Shop around, because some suppliers think
they are made of gold.  The ones from
Ukraine and Russia are usually good,
but there are exceptions. These from Russia
are also garbage.  Threw them all in the trash:
https://www.ebay.com/itm/274483321049

Do NOT buy the blue or red dipped ceramics.
These are Chinese garbage and useless at RF.

Here's the one I prefer.  They show-up on
Ebay from time to time.  You should grab some.
https://photos.app.goo.gl/giUwmLB9uDmDEEPq8

For 75-80 Meters, use 100 pFd.  It connects in series
with your coax center conductor and Antenna
connector, NOT to ground.
For 40-30 Meters, just switch the lower-left
control to "SERIES."  This places an internal 50 pFd
cap in the circuit and the rig will tune right up
on those bands into your 50-ohm load.
I don't remember what I used for 160M,
but it was somewhere between 750 pFd and
1000 pFd, a good USA- or UK-made high voltage
disc ceramic.

In this video, the transmitter ANT post
is connected to a coax jumper.  That runs
to the Wattmeter (not using the tuner-
using the dummy load).  The coax
jumper center conductor goes to the cap
and the other end of the cap goes to the
SO-238 center pin connection.  Coax
shield to ground, of course.  Here is the
result of this configuration on 75M:
https://photos.app.goo.gl/cWKT5nhQbKuhWJaT9

Everyone do what they think best, of course.
As for me, "simpler is better."

GL OM ES 73 DE Dave AB5S


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