[Kenwood] Mic Connections for Kenwood TS480

[Dennis Bradley, N5TZ]

Mac:

I posted to their internet site not here so I don't know the channels it 
goes through. After some experimenting and looking at the schematic for the 
radio the problem characteristics are as follows :

1.) There are no problems with any microphone as they have no path back to 
radio ground. I haven't had any issues with any mic I''ve tried (Kenwood 
including the stock mic and Kenwoods HM 57/58 touch tone mic, Heil GM5, etc.).

2.) There are no problems using external equipment (Rigblaster, W2IHY, etc) 
when powering such equipment through an isolated supply (wall supply, 2nd 
12v supply, etc).

3.) The problems show up when you want to power all the external devices 
and the radio via a common 12v supply. This arrangement causes some sort of 
feedback problems with the audio (and I've tried several different 
supplies, including switching, analog, etc).

Using pin 3 as audio ground and pin 5 as radio ground in item 3 above 
solves the problems.

So unless your in category 3 you will most likely not ever have any issues.

Dennis


At 09:03 AM 3/10/2005, you wrote:
>Dennis, Mac again I don't have anything connected to the rig, YET, i.e.
>rig blaster, but I'm wondering was that just with the hand mic that came
>with the radio? I'm surprised you haven't received a reply yet because
>I've seen inputs from K/Wood Customer Service on this reflector on other
>K/Wood problems and to me this is a very important question. Lets hope
>we see or hear an answer to your question soon, 73 Mac
>
>David S. McCallum/USAF RET./CMSGT/W7SAC/4
>----- Original Message -----
>From: "Dennis Bradley, N5TZ" <dennis at dbradley.net>
>To: <kenwood at mailman.qth.net>
>Sent: Thursday, March 10, 2005 8:58 AM
>Subject: [Kenwood] Mic Connections for Kenwood TS480
>
>
>All:
>
>           After wrestling with the audio feedback problems using
>external
>equipment (Rigblaster, etc) using the mic input on the radio I made some
>comparisons of the radio schematics with the manual and schematics and
>other Kenwood
>radios I have a (TS2000) that has virtually the same mic input circuit
>other than the mic connector itself. It appears there is a difference in
>the way the 480
>mic connector is wired compared to the other Kenwoods using the modular
>connector. Kenwood docs indicate that pin 3 is ground and pin 5 is mic
>audio ground, this does not appear to be the way the 480 is wired, the
>pins
>appear to be reversed (pin 3 is mic ground and pin 5 is radio ground). I
>have sent an email to KENWOOD to see if they will verify this but have
>not
>gotten a response other than the automated confirmation, we'll see what
>they say. In any case I solved my problems by reversing these
>connections.
>
>Any others have input ?
>
>Dennis
>
>
>
>Dennis Bradley,P.E. (N5TZ)      |       Fax  : 832-201-9803
>Email : dennis at dbradley.net     |       Mail : P.O. Box 79612
>Phone : 713-408-7113            |       Houston, Texas 77279
>Cell  : 713-408-7113            |
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Dennis Bradley,P.E. (N5TZ)      |       Fax  : 832-201-9803
Email : dennis at dbradley.net     |       Mail : P.O. Box 79612
Phone : 713-408-7113            |       Houston, Texas 77279
Cell  : 713-408-7113            |