----- Original Message -----
From: "Darrell Bellerive" <drbellerive.va...@gmail.com>
To: <drakelist@zerobeat.net>
Sent: Friday, June 17, 2011 3:09 PM
Subject: Re: [Drakelist] Sidetones (was Ten-Tec and Drake
Compared)
I notice that most vintage receivers provide a mute, at
least the ones
I've seen, yet it's use doesn't seem to be that popular.
Was this just
because the transmitters lacked sidetone or was there
other reasons such
as timing or poor recovery?
73,
Darrell Bellerive
Amateur Radio Station VA7TO
Depends on what you mean by mute. Most really old
receivers had a B+ switch, either for everything or for the
RF stages. This acted as a mute when used with a suitable
antenna relay. My original station used a BC-779 (Hammarlund
Super Pro). I had a relay mounted on the back to work the
B+. For CW it was bypassed simply by putting the front panel
Send-Receive switch on Receive. That left the receiver live.
I used an antenna relay but also had an auxilliary relay
right at the receiver antenna terminals. I had just enough
back wave from the transmitter to monitor my own CW. The
transmitter was a heavily modified BC-375E. I now don't
remember if it had some sort of tone generator on it for
monitoring CW. If it did I didn't use it. I am curious now
about which transmitters of the late 1940's to, say, 1960s
had some sort of monitoring tone. OTOH, there were external
monitors that would provide such a tone from sampling the
RF. I have a Bud code practice oscillator that is rigged
this way with a switch on the side to set it for monitoring.
It worked by means of a small sampling loop. None of these
tone generators would really tell you much about the air
quality of your CW signal. Listening on the receiver would
show up chirps or clicks right away as well as indicate the
shaping of the characters. I remember some transmitters,
maybe Collins S-Line, having a very identifiable fast attack
long decay characteristic that gave them an odd chime-like
sound.
--
Richard Knoppow
Los Angeles
WB6KBL
dickb...@ix.netcom.com
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