----- Original Message -----
From: "Darrell Bellerive" <[email protected]>
To: <[email protected]>
Sent: Friday, June 17, 2011 12:15 PM
Subject: Re: [Drakelist] Ten-Tec and Drake Compared
I notice the use of sidetones, and receiver muting does not
seem to be
commonly used in separate operation on the same frequency.
Obviously
sidetone would be needed when operating on different
transmit and
receive frequencies.
I have often wondered about the lack of sidetone circuits
in vintage
transmitters. I have always had transcievers and sidetone,
so it all
just seems odd to me. :-)
73,
Darrell Bellerive
Amateur Radio Station VA7TO
I think it depends on how vintage. The first Collins 32V
transmitters had side tone but it was discontinued in the
32V-3, the reason given was that they could not meet TVI
suppression specs with it. I think most of the Johnson
transmitters had it. Not sure of others. Side tone is useful
if you are transmitting on a different frequency than
receiving, common for DX. For other purposes I always
monitored in the receiver, there being enough leakage signal
so that I could hear my own.
There are a lot of curiousities in both receiver and
transmitter design and features offered. For instance,
Johnson included a speech clipper and filter in the Valliant
but Collins never did in the 32V series although they did in
the much more expensive 30K and KW-1. It may have been
simply a matter of cost.
One of the few places where a thorough analysis of
design and cost can be found is in the Collins documents for
the R-390A. This was probably a much more thorough
investigation than was typical for a production product
anywhere outside of the telephone company. At some point, in
any project, one has to stop trying to make it better and
begin to make it or decide that it shouldn't be made at all.
In the case of the R-390 the cost of all that investigating
was probably absorbed by the government contracts (meaning
you the taxpayer), in general, development costs have to be
paid for out of profits, if any, on a new product so that
when a project is cancelled it can be quite expensive. I
don't know that a lot of absolute dogs got into production
but at least some did. To me the Hammarlund Pro-310 is the
prime example, a very poor receiver however sexy looking,
that should never have been approved for production. It
would be interesting to know what had happened at Hammarlund
that led to this since they seem to have fallen off the edge
altogether at about that time.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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