|[AMRadio] Receiver Muting|
AAR7IR at Hotmail.Com
Fri Jan 10 18:00:15 EST 2014
I would be very much interested in seeing your plans if it isn't too much
trouble. I have at least 7 years of ER, perhaps you can first tell me what
year/month you published? I will probably substitute an Arduino mini
controller for the RTL logic gates because I have many of them laying around
here and I'm comfortable working with them. I also have mercury wetted
relays in my junk box and that would be a great application for them.
Thanks for sharing,
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of JAMES HANLON
Sent: Friday, January 10, 2014 5:18 PM
Subject: Re: [AMRadio] Receiver Muting
I run a bunch of receivers and transmitters together, two groups of twelve
to be exact, and I use the extra RF gain control in series with the existing
RF gain control to ground technique with the receivers. I've built up a
break-in keying system out of simple, discrete RTL logic gates and several
mercury wetted relays. The relays are very fast, they do not "bounce" on
contact closure or opening, and they are very low resistance when closed.
They will handle currents up to several amps when closed, and they don't
mind switching at least 300 volts, so they handle cathode-keyed rigs very
nicely. I sequence them with the RTL logic system so that the first thing
that happens upon key closure is that my antenna is transferred from the
receiver to the transmitter and a transfer relay in the receiver with its
swinger grounded opens across the added RF Gain (monitor level) control and
closes across the receiver antenna terminals, thus setting the receiver up
to become a good moni tor for my transmitted signal. The next thing that
happens is that I get a relay key closure for the oscillator and low powered
stages in my transmitter. After that I get a relay key closure for the
amplifier stage of my transmitter. When I open the key, the relays open up
in the reverse sequence. The whole thing follows my keying to well over 30
wpm which is about as fast as I ever go. I can control the monitor volume
level by adjusting the extra RF Gain pot, so I can make it the same level as
the incoming signal.
If anyone is interested I can supply details on the break-in keying system.
I wrote it up for Electric Radio magazine several years ago. My friend,
Mac, WQ8U, duplicated it for his rig, so it can be done.
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