[TenTec] On Noisy Transmitters

[Rick - DJ0IP / NJ0IP]

Ken, the noise we are talking about is called "phase noise" and none of
these radios had any phase noise (by design).

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Ken Brown
Sent: Sunday, July 06, 2014 8:50 PM
To: tentec at contesting.com
Subject: Re: [TenTec] On Noisy Transmitters

 > Just for kicks, try this with an old analog radio. It would be very rare
for it to have broadband noise because it has no synthesizer. 
Actually it can't have any, but maybe there is a way that I am >unaware of,
so I'll just call it rare.

I'd find it interesting to know what the measurements for transmit noise are
for older style radios. I suppose there would be about three types of
transmitters to consider:

1) Crystal oscillator, multiplier, power amplifier rigs.
2) VFO, multiplier, PA.
3) Transmitters using an IF, with heterodyne conversions using a VFO and
crystal oscillators to get to the output frequency.

My guess is that all of these configurations have very little wideband noise
or phase noise. Any of them could have key clicks, which could be fixed with
the right envelope shaping components. Any of them could have excessive
harmonics, and the heterodyne conversion style could have various spurs from
undesired mixes and images in the heterodyne conversion process. Any of them
could mess up a whole band when operating in phone modes with the mic gain
too high. Overall I would guess that every one of these old style rigs would
have less "in the same ham band noise" than most new rigs. Thess kinds of
measurements were seldom if ever made in product reviews back when those
rigs were being manufactured. I wonder if some well equipped radio lab has
collected any of this kind of data?

DE N6KB
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