[Elecraft] QRO Choices
Vic Rosenthal
[email protected]
Tue Jan 15 20:29:01 2002
Bill Myers wrote:
>
> What amplifier brands work, and what
> problems are typical with the QSK issue.
The TenTec amps, I believe, come with QSK. Some others (QRO Technology, Alpha,
e.g.) also have models that include QSK, and other brands may have it as an
option. QSK amps tend to be expensive.
Basically there are two solutions: PIN diodes and Vacuum relays. Each has its
proponents: the PIN diodes are faster, but can be damaged by static electricity
or high SWR (read: in the heat of a contest you transmit full power into the
wrong antenna). Vacuum relays have a finite life, but are available cheaply as
pulls, and are hard to damage.
I use a reed/vacuum relay setup which I've built into two miniboxes. I use
double male coax adapters to mount them right at the input and output terminals
of the amplifier. That way, I can use the system with any amplifier. I key it
with the amplifier keying circuit shown on the Elecraft web site at
<http://www.elecraft.com/Apps/Amp_keying_ckt.htm>.
The QSK circuit itself is described by Rich Measures AG6K, at
<http://www.vcnet.com/measures/D.a.07.GIF>. Rich sells a kit of all the parts
needed (except for vacuum relay, connectors, etc.) quite reasonably. Vacuum
relays can be obtained from Allen Bond at <http://www.mgs4u.com/president.htm>.
I find that this system works quite smoothly with the K2 and my Henry Radio
SS750HF solid state amp. I've removed an attenuator from the amp and cranked up
my K2 a bit, and I now get from 400-800 watts from the amp (depending on band)
when driving it with the K2 on CW.
73,
Vic, K2VCO
Fresno CA