[TenTec] Mic Extension Cable Doesn't Work

[John Huffman]

Bob -

Thanks for the explanation  I soldered the shield, pin 2, and the shell on the 
Pegasus end all together.

Didn't help.

I do have more symptoms to report.

All testing done with transmit disabled.  No RF is being generated so RF getting 
in is eliminated as a problem.

If I press the PTT on the 706, the 706's light goes on and it keys the rig.  The 
rig remains keyed and pressing the PTT won't turn it off.  But, while the PTT is 
locked if I press the VOX button, the PTT button now works and keys and unkeys 
the rig.  The light, however, remains on.  If the Pegasus is in VOX mode, 
speaking into the mic keys and unkeys the rig correctly.  But, no amount of 
pushing the VOX button will disconnect the microphone from VOX mode.  Pushing 
the PTT and then VOX doesn't work either.

I appreciate the help already received and further suggestions will be welcomed.

73 de NA8M
John

> The shield should be connected to pin 2 and the connector shell at the
> transceiver end.  Based on your description, the shield is floating and is
> thus not at system ground potential.  Hence, RF getting into the cable and
> keeping the PTT circuit in the base of the mike latched on.
>
> In audio, the rule is:  Shield is shield and is thus not a current carrier.
> Shield should be connected to ground at the load end only.  Thus the shield
> from the mike to the connector is connected at pin 2 of the female mike
> connector which is the same point that a ground wire from the mike is
> attached.  Then on the extension cable male, pin 2 only has the wire
> designated as ground and shield is not connected.  Then at the transceiver,
> the female cable connector has the ground and shield connected together.
> With this method there is a dedicated ground wire from one end to the other
> and the shield is connected at one end only.
>
> 73
> Bob, K4TAX
>
>
>
> ----- Original Message ----- 
> From: "John Huffman" <hjohnc at adelphia.net>
> To: "tentec" <tentec at contesting.com>
> Sent: Wednesday, December 28, 2005 7:49 AM
> Subject: [TenTec] Mic Extension Cable Doesn't Work
>
>
>>I have a new Ten Tec 706 microphone that I'm using with my Pegasus.  It
>>works
>> fine, no problems.
>>
>> The cord is too short, so I bought an extension cable with a 4 pin female
>> connector on one end.  I wired a 4 pin male to the other end.  I connected
>> the
>> extension cable to the Pegasus and the mike to the other end of the cable.
>>
>> Audio works fine, but the PPT button and the VOX button on the microphone
>> won't
>> go off.  You have to unplug the mike from the cable to get them to go off.
>> I
>> start with the buttons off, all is well. I push either button and it locks
>> in
>> the on position.
>>
>> I've checked the cable a dozen times.  Pin 1 goes to pin 1 and nowhere
>> else.
>> Same for pins 2, 3, and 4.  None of the pins are connected to the shield
>> of the
>> cable or the shells of the connectors.  None of the pins are shorting
>> against
>> each other.
>>
>> This even happens when I have the "Xmit Disable" button pushed on the N4PY
>> program, so no RF is causing the problem.
>>
>> I'm guessing it may be a ground problem with the PTT circuit in the base
>> of the
>> mike.  I've tried jumpering the shells at each end of the extension cable
>> with
>> no luck.
>>
>> I am at a loss to understand how extending 4 wires would cause the PTT to
>> lock
>> on.
>>
>> Any suggestions will be greatly appreciated.
>>
>> 73 de NA8M
>> John
>>
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>>
>
>
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