[amsat-bb] TS2000 Downconverter mounted on Tower
john at papays.com
Fri Dec 2 17:49:41 PST 2011
The suggestion to mount the converter on the tower
near the antenna might have some good results, however,
there are two problems. The first is that you will need
two coax relays or a transfer switch up on the tower to
switch the converter in and out of the circuit. Then you
have the potential to transmit into the converter when you
are uplinking on uhf if you forget to switch the relay. When
you mount the converter in the shack, you can use an inexpensive
You could use a single relay with two feedlines. One would
be for the converter output which goes to the rx aux ant jack.
That line could be lossy since the converter has some gain
and the 10 meter output will be attenuated less than at UHF.
The other would be your best coax and would connect to the
type N port on the TS2000. This would prevent any possibility
of transmitting into the converter. In other words, the
antenna would be switched to the converter input or directly to
the TS2000 Type N connector.
The second problem is that when you have electronics with
frequency determining elements (crystal oscillators) mounted
outside, temperature variations will cause drift. Having
the converter inside stabilizes the temperature and the
converter doesn't drift. Mounting electronics outside
also requires special attention to keeping things dry. It's
just a lot easier to keep things inside and use good quality
coax. Heliax is often available at prices not much greater than
LMR400 etc. If sealed up, it will last a lifetime.
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