If the hand mike works fine, then the issue is NOT inside the radio but 
outside of the radio.
 As to using  a headset type mike, the proper values resistors and a DC 
coupling capacitor will be needed.   In my case, I was able to put these 3 
components inside the 8 pin mike connector.  It is a tight fit with two 1/8 
watts resistors and a 0.1 mfd capacitor.
 As a side comment, if you intend to use a "cheap" headset then expect equal 
results.  You will find that most Electrect mikes have much higher output 
level than dynamic mikes and some consideration for level adjustment must be 
made.  In this case, adjustment of the hardware mike gain will be necessary. 
Once this is done then the hand mike will not work satisfactorily for VOX 
operation.  Hence the value of the 2 resistors will need to be chosen such 
that the effective Electrect mike output is about equal to that of a dynamic 
mike.
 If your mike is a single wire mike then the circuit and resistor values will 
be different than a mike that is a 2 wire mike.  There's both types 
available.
73
Bob, K4TAX
 ----- Original Message ----- 
From: "John" <k4avx1@windstream.net>
To: <tentec@contesting.com>
Sent: Saturday, August 23, 2014 11:18 AM
Subject: [TenTec] MIKE & Eagle
 
I've had good luck on the older TT's using a computer mic on
them for contesting using the vox in the radio and the headset.
 I have tried different
circuits with the Eagle, using the 9 V. line for the mike, and
using a circuit with a 9 v. battery dropped to 5 v. regulated.
So far, no circuit works.
I'm thinking maybe the gain control internal to the Eagle
might need to be adjusted.  The hand mike works fine
on VOX, but I want a cheap headset, and don't want
to spend a fortune on a "ham" headset.
Any ideas??  Anyone had experience with another
mike besides the TT one?
Thanks,  73,
John, K4AVX
k4avx1@windstream.net
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