[CW] "Amp Sequencer"

[N2EY at aol.com]

In a message dated 5/18/05 7:52:20 PM Eastern Daylight Time, n1ea at arrl.net 
writes:


> 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.

Is this meant for true QSK, or simply as a foolproof form of TATTOO 
(Transmitter Automatic Turner On-er/Offer)?
> 
> 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.
> 

Vacuum relay can do a lot faster than 10 ms.

> 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?
> 

The modern trick for QSK is to use vacuum relays or PIN switches, and a rig 
that is set up for separate rx antenna input, so only one relay has to switch.




> 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.

btw, the NCL 2000 is grid driven, but has a passive grid circuit.

73 de Jim, N2EY