[TenTec] Orion's break in

[Paul Christensen]

> That's interesting to hear because I don't get such fast QSK with my
> O II.

I just discovered that extremely fast QSK may *not* be a good thing whether 
its from a Ten Tec or not.  On the K3, there's a "QRQ" menu option that 
allows for blistering fast QSK -- almost to the point where your own 
sidetone becomes just another signal on the band.

This sounds like a good thing, right?

It is except under certain ionospheric conditions.  For the past week, I've 
been noticing audible, high intensity "clicks" after each keyed element 
during the daytime on 40m CW.  I thought I had a problem with my PIN-diode 
switching system.  But after scope measurements, nothing is wrong with my 
set-up.  Here were some of the conditions with QRQ mode engaged:

- Clicks heard much more at high power (1KW) than at 100W.  Clicks gone 
completely under 50W.
- Clicks noticeable on 40m, but only during the day.  Weak echoes heard at 
night on 40m.   No other bands affected at any power level, nor other time 
of day.
- Also, within the last month, my 80m dipole which is normally at a height 
of 60 ft, is now at just under 40 ft while I make a new set of 600-ohm open 
feeders.

See a pattern developing here?

The problem has been severe only recently, especially with the temporary 
1/4-wave dipole height on 40m.  The dipole at that height is producing a 
take-off angle straight up at 90-degrees (i.e., NVIS).   When the dipole was 
up at its usual 60 ft height, the 90-degree lobe almost completely 
disappears since the dipole is about 1/2-wave above the ground.  Conditions 
on 40m have been strange at night too as I'm hearing my echoes but not 
clicks. However, as the band goes long in the evening, I think the NVIS path 
disappears and some other ionospheric factor is responsible for the weak 
echoes.

The F1 layer is roughly a 400-mile round trip, longer to/from F2.  At the 
speed of light, a 40m transmission launched at a 1/4 wave in height during 
the day shoots straight up and is returned approximately 2 ms later in time, 
perhaps double that time at night via only F2. The K3 has a super fast 
switch time from Tx back to Rx.  How much?   I don't know yet, but I'm going 
to measure it this week with a digital storage scope.

If I switch back to normal QSK which is still very fast (akin to TT), the 
problem completely disappears day and night.  The only explanation I can 
offer is that in QRQ mode, the receiver is recovering within 2 ms after Tx 
during the tail end of the ionospheric return.  Perhaps only 1 ms of my own 
signal is being heard, thus resulting in what sounds like a click and not a 
tone during the day.  But at night, I hear the tone as an echo when the band 
goes long.

So, while I never would have believed one could have QSK that is too fast, 
I've all but convinced myself that under the right conditions -- it can be 
too fast.  I'll know more about the Rx recovery time after my T/R 
measurements this week.

Paul, W9AC