|[AMRadio] 7160 tonight: Suggestion|
macklinbob at msn.com
Thu Apr 2 21:00:12 EDT 2009
You had to be on 75, 40, or 20 AM in 57 and 58 to really appreciate the
problem. In the evening 75 and 40 phone segments were wall to wall AM QSOs.
The hetrodyne noise was terrible. During the daytime the 20M phone segment
was the same way.
At this time SSB was the new kid on the block.
The advantage of AM is that you do not have to critically tune the Rx if it
is a classic BA. The VFOs of that period were also not precise.
Kent (Seattle), Wa,
"Real Radios Glow in the Dark"
----- Original Message -----
From: "Jim Wilhite" <w5jo at brightok.net>
To: "Discussion of AM Radio in the Amateur Service"
<amradio at mailman.qth.net>
Sent: Thursday, April 02, 2009 3:15 PM
Subject: Re: [AMRadio] 7160 tonight: Suggestion
> These are the arguments I remember from the mid 50s about why we
> needed to restrict bandwidth of our transmitted signals. Also the
> fact that there were so many more hams that were on the air.
> Collins lead the way with the 75A1A which, with modifications would
> have, what, 2.4 Kc bandwidth? Other manufacturers followed suit.
> Most receivers and transceivers have 2.4-2.7 Kc bandwidth at the
> most. So the outcome was the ARRL supported SSB to double the
> number of stations that could transmit at the same time. Today
> people are decrying the fact that there are fewer hams than in past
> years. That should give us more space.
> Today we modify our rigs to utilize from 100 or so cycles out to
> 8-10 Kc so we sound better. Even the SSB crowd is doing it out to
> about 5 or 6 Kc. I'm sorry my WRL VFO is not stable enough to stay
> on one frequency for an extended period. It does wander at least
> 100-500 cycles between transmit and receive.
> So if someone using a modern transceiver wants to move about 1.5 Kc
> near me, they better have an auto notch function or be prepared to
> change the notch knob as my VFO wanders. Last I read part 97 there
> are no standards for frequency stability on the ham bands.
> I do try to be considerate, I just wish the SSB crowd, especially
> the contest and DX bunch would try.
> >I see this all over, and its just poor operating practice.
> > Some guys will be 2 or even 3 KHz low, someone else might be 1 or
> > 2 KHz
> > high, some guys are overmodulating and/or have no restrictions on
> > the high
> > end of the audio, and the qso is 10 KHz wide, which is rude.
> > Not so important on an empty band, but still poor operating
> > practice all
> > around.
> > I know its hard to keep some rigs on frequency, you need to zero
> > beat often.
> > When I had the drake R4C, sometimes I only heard one guy in a qso,
> > the other
> > guy was out of the passband!
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