[AMRadio] Re: GB> AM vs SSB???


Bob Macklin macklinbob at msn.com
Fri Apr 6 20:04:10 EDT 2007


Soe of you people should have been around in 1958 at the peak of the best
solar cycle in recent memory.

In those days SSB was not the predominent phone mode. AM was. SSB was the
NEW KID ON THE BLOCK. There were realy very few SSB recievers and most of us
hams could not afford them. The two that I remember were the 75A4 and
NC-88(??). If we wanted to listen to SSB we had to learn to tune our GC
receivers to it.

It was detemined that the audio band needed for COMMUNICATION QUALITY voice
was 300CPS to 2700CPS, That is where the 2.7KC SSB filter came from.

The receivers for this mode were made for PUNCH, not to sound good.

My SX-110 sounds reall good on AM but it is a piece of crap for SSB. But I
think it was manufactured before SSB began being commonly used on the ham
bands.

Bob Macklin
K5MYJ
Near Seattle, Wa

"Real Radios Glow In The Dark"
----- Original Message ----- 
From: "Grant Youngman" <nq5t at tx.rr.com>
To: "'Discussion of AM Radio in the Amateur Service'"
<amradio at mailman.qth.net>
Sent: Friday, April 06, 2007 4:43 PM
Subject: RE: [AMRadio] Re: GB> AM vs SSB???


> The main reason ssb will sound better on a collins than on some of the
> cheaper rigs is that their audio chain has 1% distortion instead
> of the usual 10% distortion, and they also use a decent loudspeaker.

Actually, I've never thought Collins SSB sounded all that terribly good.
The KWS-1 has a bit wider transmit filter than the other usual suspects, but
in general, the transmit bandwidth is too narrow.  There are important audio
queues in both the low end and high end (up to 4Khz or so) speech spectrum
that are completely missing.  This isn't just a Collins problem -- I'm not
singling them out to pick on.  And the typical receiver, with it's shiny 2.1
Khz mechanical filter or equivalent, chops those important queues out even
if they were being transmitted.

I am not a proponent (nor opponent, either) of high fi SSB, but you don't
have to go too far beyond what is the politically correct norm to get a
signal that can actually be well understood (per Bacon's point).

And of course there are other factors -- tuning errors, distortion products,
a heavy hand on the "processing" control, what-have-you.  AM signals can be
mushy and hard to understand, too.

Grant/NQ5T

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