I've been using the MFJ Matchmaker and it does a good job. I really
like being able to tune without putting a signal on the air.
Previously, I used the Palomar Tuner-Tuner. It's the same theory, but a
different implementation.
The big difference is what happens when you screw up and transmit into
the unit. The MFJ has a circuit to automatically by-pass. The Palomar
has a 1/16 amp fuse. When using the Palomar, I had to stock up on the
fuses :-)
You do have to tune on the air to find the general settings of your
tuner for the frequencies you normally use. You log those tuner
settings. From then on you can use the Matchmaker to touch up the
settings without putting a signal on the air.
I find I have to have the attenuator on to use the matchmaker. Sure
wish I the unit had an adjustment for the noise level it creates.
73 de K1ESE
John
Kevin Purcell wrote:
It could even be a useful retrofit into existing rigs -- especially
easy in rigs that run 50 ohm connections between separate boards.
A minor problem I see of putting it in the receive line is there is
usually a LPF filter beyond the TR switch (shared between the Tx and
Rx) designed for 50/75 ohms. Given an 50 ohm load (or particularly a
reactive load) you might see a transformation through the LPF. But a
50 ohm resistive load on the antenna connector will still look like a
50 ohm resistive load on the other side of the LPF.
Still it's easy to do: a resistive bridge, a pulsing noise source (or
even a continuous one, but the former is easier to hear) and some
switching in out (and turning off the noise source).
On Sep 30, 2007, at 9:41 PM, Dr. Gerald N. Johnson wrote:
On Sun, 2007-09-30 at 20:54 -0700, Denton wrote:
I have very often wondered why these newer rigs do not have a
built in noise
bridge!
It sure wouldn't be complex to do... just a bit of switching to insert
in the line and it might well be the receive line so that it never had
to see transmit power...
73, Jerry, K0CQ
--
Kevin Purcell
kevinpurcell@pobox.com
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