[Top] [All Lists]

[TenTec] Fixed: TT 700 Hand Mic

To: tentec@contesting.com
Subject: [TenTec] Fixed: TT 700 Hand Mic
From: K8JDC <K8JDC@sbcglobal.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 18 Dec 2010 20:35:16 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
For what it is worth, I got rid of the big spike by making two changes.  
First, there was a 2.2K resistor in the power line leading to the mic 
element.  This resistor is between the PTT switch and the element so I 
increased that to 22K.  I tested it with a resistor substitution box and 
the mic output was unchanged until the resistor value got to about 33K.  
At 22K, the output level is the same as before so it is not too much 

Secondly, there is a capacitor from the positive terminal of the mic 
element to ground.  I added extra capacitance at that point and those 
two changes got rid of the spike completely.  My theory was to prevent a 
voltage spike from being supplied to the mic element.  So, between the 
larger resistor and the larger cap, it allows the voltage to build up 
quickly instead of being a sudden power spike.  The audio output level 
is the same as before the changes and the audio quality also seems 
unaffected to me.

Just thought I would post what I did.  It was spiking to 100W every time 
I keyed the mic before the fix.  I'm not sure why but I'm happy with it now.

TenTec mailing list

<Prev in Thread] Current Thread [Next in Thread>