[TenTec] Tuning Rigs

[John Huffman]

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 at pobox.com
> 
> 
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