D104 Question

[Bob Peters]

Hi Edwin and list...Again I will put  my  bucks worth  in....The 
D104  after about 1975 was designed to
be used with the pre amp in...This is according to  the head engineer at 
Astatic and the National Sales Manager...
They  both say that it was part of the EQ  curve  because of the terrible 
xtal elements out of Asia...Astatic stopped making there
own about 1972....It was not made to make a CB sound louder...This is from 
the horses mouth...My Golden Eagle and silver Eagle all
have amps in and work  great...See ya all at HAMCOM this weekend...

de W1PE  Bob


At 02:18 AM 6/19/03 -0600, EDWIN J FORWOOD wrote:
>All points well taken and agreed.  I had not noticed the hum problem.
>However I rarely work close stations on HF.  More usually on VHF.
>73 de Jerry, KØEJF
>
>On Wed, 18 Jun 2003 13:08:06 -0700 (PDT) Glen Zook <gzook at yahoo.com>
>writes:
> > Although my Heath SB equipment will work fine without
> > the amplifier, I have found that by using it that I
> > can keep down the microphone gain (usually run it at
> > about 9:00 o'clock with the preamplifier) which
> > results in much lower hum and noise on the transmitted
> > audio.  On my SB-110A this is well over 30 dB less
> > hum!
> >
> > The hum certainly meets specifications without the
> > preamplifier in use.  But, for example, when I am
> > working a local about a mile away my hum level runs
> > about S-8 when I am not using the preamplifier.  Of
> > course I am a true "60 dB over S-9" on my peaks.  When
> > I reduce the gain and then use the preamplifier, he
> > can just hear the hum and I am still "60 dB over S-9"!
> >  Of course, stations over 3 or 4 miles away cannot
> > hear the hum no matter which way I run the microphone.
> >
> > My Collins S-Lines, on the other hand, seem to have a
> > lot more gain in the audio chain and are definitely
> > over driven by the D-104 with the preamplifier.
> >
> > My Heath Apache and DX-100 work fine either way and my
> > Hammarlund HX-50A likes the microphone with the
> > preamplifier a bit better but will work fine without
> > it in use.
> >
> > Most problems are due to the fact that the microphone
> > gain on the transmitter is not reduced by many
> > operators to compensate for the gain in the
> > preamplifier.  Thus, the audio circuits in the
> > transmitter are overdriven and definitely distort.
> > Also, like in my Collins S-Lines, in many rigs there
> > is already so much gain available that using the
> > microphone with the preamplifier engaged is just
> > asking for trouble!
> >
> > That is why I rewired my D-104 with a switch that
> > allows me to engage the preamplifier when the rig
> > works better with it.  I have a switching box set up
> > so that I can use the same microphone on a number of
> > different rigs.  Not only do I switch the microphone,
> > but I also switch the push-to-talk function on the
> > microphone and on a foot pedal as well.
> >
> > Glen, K9STH
> >
> >
> > --- EDWIN J FORWOOD <e.j.forwood at juno.com> wrote:
> >
> > While it is true that some equipment may have some
> > additional gain when using the amplifier in the base
> > of the D104, I have found that none of my Heath SSB
> > equipment really need it.  The usual result is that a
> > lot of people ruin their audio output due to over
> > driving when using the amplifier.
> >
> > =====
> > Glen, K9STH
> >
> > Web sites
> >
> > http://home.attbi.com/~k9sth
> > http://home.attbi.com/~zcomco
> >
> > __________________________________
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> > http://sbc.yahoo.com
> >
> >
>
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Best 73's  Bob W1PE
Mesquite, TX 75149

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