[TenTec] OT: Sound Recording artifact with Gold line mike

[Mark Erbaugh]

Stuart,

I was wondering if an isolation transformer would help.  I've got one so I
just need to put the right adapters on it.  I don't know the exact
mechanism, but I believe that the Heil element is dynamic and thus doesn't
need any power.

I forgot to mention that I did try turning off the monitor. It made no
difference.

73,
Mark

----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: "Mark Erbaugh" <mark@microenh.com>; <tentec@contesting.com>
Sent: Thursday, April 05, 2001 4:28 PM
Subject: Re: [TenTec] OT: Sound Recording artifact with Gold line mike


>
> A high quality microphone such as the Gold line works better from the
> standpoint of stray pickup if audio is coupled by a 1:1 microphone
isolation
> transformer, if the audio level right out of the Heil is adequate in
level.
> A step up transformer for the audio would be used if both isolation and
gain
> is needed and impedance matching.
>
> Most ham transceiver inputs however, are low impedance compared to the
older
> models, and thus you need to look at the spec sheet for both mike and rig
> mike input circuit to know which to do.
>
> Sounds like the case of the Heil commons a power ground and the audio
shield
> ground, which it might if it has a Fet element.  The case then, is picking
> up some computer artifacts or switching.  You might do a further test of
> where it is originating, by turning off THE MONITOR.  Many of those are
high
> RFI sources right from the CRT!
>
> 73,
> Stuart K5KVH
>
>
>
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