[TenTec] Argo V Transmit Audio

[Thomas Thornton]

A few comments about my experiences so far with the
transmit audio on the Argonaut V -- aka TT-516.

My expectations at the outset were somewhat shaped by
experiences with the Scout (which I loved and wish I
had not traded).  On my specific 555, the ALC usually
was happiest at about three o'clock which roughly
equates to 75% gain.  Trying that with the Argo V
resulted in audio reports of topping out or flattening
of the audio with significant distortion.  So... I
turned the ALC down to where my listeners could no
longer hear the distortion -- about 8 or 9 o'clock
(25-30% ? ) -- but at that point the ALC light and
needle deflection was almost nil.  But to avoid
distortion I continued to operate at about 9 o'clock
or what I figure to be about 33%.

By the way -- a majority of this was on 40m SSB --
although I have tried on other bands with similar
reports.

Troubleshooting...  I replaced the mic with another
brand new (6 months old) Ten Tec hand mic.  Exactly
the same results.  Same problems at the same points.

My thinking is that the problem lies in one of three
areas:  poor operator; fault specific to my radio;
engineering fault.  I normally work on the assumption
that the problem lies with operator head-space as that
often is the case.  No luck so far.

So... going backwards, I decided to try a different
mic.  I contacted Heil to see if one of their mics
would work -- their response was 'ask Ten Tec.'  The
answer from TT was that the Heil series mics do not
have enough output to support the Argo V.

I looked at the specs.  The Argo requires 5 mV or -67
dB (200-50k ohm).  The Heil HC cartridges operate 1000
ohms at 1kHz and put out between -66 dB (HC-4) and -68
dB (HC-5).  Looks good to me -- or was I missing
something.

I have a Heil mic that I use on another radio, and
yesterday a cable arrived from AES to connect the Heil
Goldline to the Argo V.  Magic.

Great audio reports.  No topping out or distortion. 
ALC gain set anywhere from 9 to 3 o'clock resulted in
good clean audio reports (with obvious changes in the
audio level as I increased the ALC).

I will allow the rest of you to draw the conclusions
-- I have my own.  So now I think the answer is to
replace the stock handmic with a Heil HMM (I want to
run the Argo mobile-portable and the Gold Line is a
bit cumbersome.

For those of you that have actually read this far...
thanks for the interest.

Tom  ah6zz
Honolulu

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