[TenTec] din connector, etc.

[Jim Brown]

On Thu,9/25/2014 9:02 AM, Roy wrote:
> I operate everyday from 35 wpm to 45 wpm with QSK amplifiers. With the 
> built-in Eagle keyer, transmitted weight is perfectly adjustable 
> internally and with an external key or keyboard, weight is also 
> perfectly adjustable using the weight controls on the external keyer 
> to compensate for truncating effect of  the 17ms. And again, of course 
> Eagle works QSK with QSK amps.!!! 

Thinking more about this -- the ARRL scope traces compare the RF output 
of the rig with the keying signal. This is NOT the same as the output of 
a power amp being keyed by the radio.

I think we need to define a QSK amplifier. There is more than one way to 
do it. The original Ten Tec way -- you key the Titan and the Titan keys 
the radio. The limitation of this setup is that the rig must have a very 
short delay on the RF signal. All amps, including the Titans, accept a 
DC keying signal (either a DC short or +DC). As Rick has noted, amps 
with vacuum relays switch very quickly, and can follow keying to fairly 
high speeds.

And there's also the matter of what does the operator listen to in order 
to decide if his keying is being shortened. If he listen to sidetone in 
his headphones, that is generated in the rig, and does NOT accurately 
represent the actual output of the rig or the amp. It's only what he's 
TRYING to send with his keyer or key. To hear what we are ACTUALLY 
sending, we must listen on a second radio (with no antenna connected and 
the RF gain turned all the way down)!

Looking at ARRL test reports for the Eagle and the TS590S -- the "TX to 
RX turnaround time" for the Eagle is 70 msec" and 20 msec for the 590. 
So, as Rick noted, at high keying speeds we're not going to hear between 
the dits, even barefoot. For both rigs, there's no shortening of the 
dits in full QSK at 60 wpm, and if the key signal to the power amp is 
coincident with the keying signal to the rig, an amp with a vacuum relay 
or diode switching should reproduce the keying waveforms, while an amp 
with open frame relays is likely to hot switch (unless there's a speedup 
circuit).

73, Jim K9YC