[Amps] Alpha 9500 Idling Current

[Vic Rosenthal 4X6GP]

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