Re: [TenTec] Using a comptuer microphone with a Triton 4 (544)

["Bob McGraw - K4TAX" <RMcGraw@Blomand.net>]

Interesting........ the non amplified D-104 that I use on the Collins 32S-1 
always receives "outstanding audio" reports.  I guess that's due to a crappy 
radio and crappy microphone combination.
73
Bob, K4TAX


----- Original Message ----- 
From: "Dr Gerald N Johnson" <geraldj@storm.weather.net>
To: <tentec@contesting.com>
Sent: Friday, November 16, 2007 10:36 AM
Subject: Re: [TenTec] Using a comptuer microphone with a Triton 4 (544)


> On Fri, 2007-11-16 at 07:25 -0600, Bob McGraw - K4TAX wrote:
> > The D-104 has proven to be a time tried consistent performer.
> > Unfortunately, many D-104 mike today have an element that is defective.
> > Defective not as in no or low output, but brittle thus one that sounds 
> > bad.
> > New replacements are hard to come by and somewhat expensive. 
> > Replacements
> > such as the Heil HC-5 work and typically sound good.  However, to drive
> > older radios, the amplified base stand is usually required.  But this 
> > then
> > is no longer a D-104.
> The D-104 is a crappy microphone for SSB, always has been. It has a
> rising characteristic intended (in the 30s) to emphasize the highs at
> the transmitter that were rolled off in the typical AM receiver IF
> selectivity that had a very rounded pass band. Further the crystal and
> ceramic D-104 were designed to work with a very high impedance load for
> solid state, preferred load a megohm. Today a high impedance solid state
> audio input impedances is likely to be under 100K. That load on a D-104
> changes it from rising to peaked and falling, makes it sound muffled. It
> it still had the rising characteristic with the solid state input Z, it
> can overdrive audio and balanced modulator with audio components
> rejected by the SSB filter unless in super wide SSB mode which draws a
> lot of fire on the bands.
> > Secondly, those with the amplified base stand may have their problems 
> > too.
> > Many due to efforts to configure them to drive different loads and 
> > various
> > PTT switching arrangements.
> Or simply from supply VOLTs of audio to an input circuit designed for a
> couple millivolts. NO ham rig has ever needed an amplified microphone.
> Amplified microphones were only needed with fixed transmit audio gain
> CBs that were intentionally very under modulated to absolutely prevent
> over modulation.
> > At the same time, in view of all of the above,  a good D-104 is an
> > outstanding performer on SSB and AM too.  The following link is very 
> > helpful
> > in wiring the mike, configuring the PTT switching and such.
> > http://www.shadowstorm.com/cb/Astatic_D-104_Papers.html
> >
> > 73
> > Bob, K4TAX
> Yes, I have a D-104 (case) hooked to my Corsair II. The cartridge is a
> Shure limited bandwidth communications element no longer made.
>
> 73, Jerry, K0CQ
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec