Hi Folks:
Several years ago, using an Elecraft design, I developed a PC board
which would allow K2 owners to key an external T-R relay for the
purposes of controlling an external QRO RF Amp, or other external
devices. Over the years that design has morphed a bit into a more
robust device, using MOSFETs, which now has the ability to key up to
+150VDC and several amps of current (if required). Fortunately, few,
if any, T-R relays require more than a couple hundred mA of current,
BUT several of the Heathkit amps do present +120 VDC as the coil
voltage on their T-R relays.
I am now offering a kit of parts, including etched, drilled and
tinned PC board, and all components, for this device. You can
download the assembly and installation instructions from:
http://www.n0ss.net/k2_t-r_rly_drvr_v2r0.pdf
Cost of the kit is $16 (US) and $17 (DX), postpaid to your mailbox.
This a proven design.
PLEASE NOTE: If you already have a KPA100 100W amp or a K60XV
60-meter adapter installed in your K2, you DO NOT need this kit since
both of the above devices already provide the ability to key an
external T-R relay. Additionally, most HF amps which use open-frame
T-R relays will NOT be able to operate at QSK (full break-in) relay
switching speeds, so you will NOT be able to operate QSK with these
amps. However, you can increase the T-R delay length (in MENU) to
eliminate most of the 'thrashing' of the relay during keying, so the
amount of 'hot switching' of the relay will be reduced significantly.
If you are interested, please contact me directly.
73 and thanks for your interest in this kit.
73,
Tom Hammond N0SS
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