[Elecraft] K2 External T-R Relay Driver Kit now available... finally!

Tom Hammond n0ss at earthlink.net
Mon Nov 13 20:26:34 EST 2006


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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