[CW] "Amp Sequencer"

[Mike Hyder -N4NT-]

What you need is an old electronic T-R switch, David.  Just keep your 
lead-length from the amplifier output to the T-R switch as short as 
possible.

73, Mike N4NT

----- Original Message ----- 
From: "David J. Ring, Jr." <n1ea at arrl.net>
To: <CW at mailman.qth.net>
Sent: Wednesday, May 18, 2005 7:51 PM
Subject: [CW] "Amp Sequencer"


Recently I saw in "QST" an advertisement for a new "Amp Sequencer".

http://netcertus.com/cgi-bin/netc/net.cgi?page=ampsequencer

This sequencer acts immediately on the keying pulse from the key (or from
the Push-to-Talk keying line) to close the relays on an r.f. amplifier (it
also handles sequencing the switching of additional preamps), then delaying
via a buffer the keying signal to the transmitter (transceiver) by an
adjustable delay (or a factory default delay) to allow the amplifier relays
to close, then the transceiver to be keyed, r.f. to be generated and
amplified, then after the key (or PTT) is released, the amplifier is
switched off after the adjustable delay (or factory default delay), the
preamp is turned back on.

What it amouns to is about a 10 ms delay before the start of the CW, and a
equal delay in holding the amplifier on.

The web page says that 10 ms delay isn't objectable, but I would think that
a 250 ms (1/4 of a second) would be nutty, but I don't know.

Is a 10 ms delay before you hear audio for your keyer irritating?  60 wpm
has 25 dots per second, which means it has a pulse length of 1/50 of a
second (1:1 dot:space ratio).  1/50 of a second is .02 seconds or 20 ms.  So
perhaps at 60 wpm where the delay is 50% of the dot it might be irratated.

But the delay could be eliminated (to the ear) by using an external keyer,
you hear the audio, the amplifier switches, the delayed key pulse goes to
the transceiver, (you have to turn the sidetone off) and the r.f. goes out
for 10 ms longer than the keyer is making a noise, then the amplifier turns
off.

Sounds sweet.

Any better units out there?

I have an old National Radio NCL-2000 amplifier which is tuned grid, tuned
plate (not grounded-grid) and runs two 8122 RCA ceramic tubes.

I'd like to run QSK but I don't want to hot switch the amplifer.

73
David N1EA