[TenTec] ten tec 1320

[Wj5mh at aol.com]

In a message dated 8/10/2003 11:31:35 AM Central Standard Time, 
wy7w at netzero.com writes:

> In other words, I do not want to hear too much receiver between dits and 
> dahs etc...

Tom,

Most operators want to go the other way by speeding the transition between 
transmit and receive to eliminate a "thump" or "click" between dits.  This is 
done by changing the value of C1 to .1mf ( or in my case...1 mf ).  Ten-Tec has 
suggested adding a 10K resistor from pin 8 of U4 (xmit mixer) to ground.

You have to remember that your receiver is always on, because it actually 
receives your xmit signal...and that is your sidetone.

Now, you may want to play with the AGC a little.  I wanted to have the AGC 
react quicker to strong signals, so I changed the value of R26 at U2B allowing 
the AGC amplifier to amplify more.  Since your receiver is receiving your 
transmit signal, changing this resistor to a higher value may quiet the receiver 
between dits.  (I say "may," because I haven't paid close attention to the role 
AGC plays during transmit.)  Also, you may experiment with the value of C41 in 
the same circuit.  Increasing this value will cause the AGC action to slow as 
the cap discharges, increasing the amount of time for the receiver to return 
to full sensitivity.

Now, R61, the sidetone level control, also plays a part in all of this, 
because it is controlling the IF gain through Q8 during transmit.

Wow, what fun...  

Have I confused you?

73,
Joe