I don't see the point of RF-operated EBS (especially for CW) unless the
driver is poorly designed. If the transceiver has a key out line that is
activated a few ms before RF is output, then that can operate the t/r
circuitry in the amplifier, including bias switching. If not, then an
internal or external sequencing circuit is a better choice.
RF-operated EBS is like old-fashioned ALC, a way of closing the barn
door after the horse is out. How can it not screw up the rising side of
a CW element?
73,
Vic, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 29 Dec 2016 20:35, Paul Christensen wrote:
"Paul, My Alpha 9500 runs 232 ma idling current with 3535 volts on the
plate no load and 3420 volts on the plate when idling. Larry, WA9MAG:
That amount of Ip idle current seems high to me for the 9500. Possibly
W6WRT and W8ZR can weigh-in with their findings. Possibly, it was set
higher in software?
The Alpha 8406 I use on 6m idles at 200+ mA, but I deliberately set it high
in software to help offset an internal EBS timing error. Hard to believe,
but the 8406 was truncating CW characters in QSK mode. It was so bad, I
first suspected a fault with the RF input sensor but it's sensing fine.
When observing a QSK-keyed CW waveform on a scope, the 9500 suffers from the
same EBS issue, albeit it's much more subtle and as is typically the case
with EBS, it only affects the very onset of the waveform.
Paul, W9AC
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