[Submitted this earlier today with a picture attached of "how I made
mine", however it seems the picture is causing the message to bounce, so
now sending w/o picture]
Is your K2 one with a PA Key out? If so, just an RCA cable and a coax
jumper.
If your K2 is a K2/100 then it will have PA key out as the KPA100
provides it. If your K2 is a K2/10 (without KPA100), then, to ponder:
On
https://ftp.elecraft.com/K2/Mod%20Notes%20Alerts/K2%20Amplifier%20Keying%20Circuit.pdf
there is an application note from Wayne on how to build a simple circuit
to get this PA KEY output. The application note suggests adding a small
PCB inside the K2.
Notice that the connector of the KIO2 ("do not connect a straight
through cable") has all the signals that Wayne's circuit needs. So, it
is possible to build this PA key out circuit on a small PCB that fits
inside the hood of a DE9 connector, the one that connects to the KIO2
connector.
Hence, it is possible to build a "KIO2 special cable" that houses the PA
KEY circuit, and also provides connectivity to pin 2, 3, 5 (only these
pins!) so that a RS232 device can be connected, and not make any change
to the K2 itself.
And there would not be a need to drill a hole in the K2 casing, find
place for Wayne's circuit - it all fits in the cabling that connects to
the K2, and, at the same time, protects the non-RS232 signals of the
KIO2 connector.
In my "special cable dongle", sharp eyes will see some deviations: I did
not connect the RS232 pins because my transverters don't need it, but I
did add a 3rd transistor (2nd 2N2222) and a LED to indicate when the PA
KEY circuit is activated. A red LED now lights when the K2 activates the
TX PA circuit.
And if you have done the Unspeakable and connected a RS232 device via a
full-wired straight cable, then you may find
http://folk.uio.no/sverre/LA3ZA/blog/K2/N0SS/k2_wrong_ser_cbl_damage.pdf
of interest. Note that updating a K2 to the "B" revision makes a number
of changes that, at least in theory, should reduce some of the damage
done. It is still best to NEVER make this mistake, though.
73, Geert Jan PE1HZG
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