[Elecraft] K2 is break-in only on CW?? Part II

[Don Wilhelm]

Jay and all,

There certainly IS a line in the K2 that can be used for sequencing
switching of transverters and other external devices.  The 8R line becomes
active about 20 ms before RF is presented at the antenna jack, and the
drop-out time can be adjusted via the K2 menu - so to my way of thinking,
the needed sequencer is already built into the K2.

The KPA100 amplifier keying output follows the state of this 8R line, and
the signal is used in the K2 to Elecraft transverter connection (KIO2) to
switch the Elecraft transverters.  For those who are driving non-Elecraft
devices with the base K2 (QRP), I suggest you look carefully at the 'K2
External Power Amplifier Keying Circuit' shown on the Elecraft website -
Builder Resources area, then select Application Notes, Eric originally
designed it for use with an external amplifier, but can do the same job with
external transverter equipment.

I believe that easy-to-build keying circuit will do the external switching
job you need - OTOH, if your external devices need more than 15 to 20 ms to
become properly active, you may still be in trouble, but that IS a
relatively long time period, even for relay operation and you may have to do
some work on the transverter end to make it switch faster.

73,
Don W3FPR

"Life is what happens when you are making other plans"
(John Lennon wrote it in a book, Mike Cross used it in a song - I don't know
who was first)

----- Original Message ----- 

>   Thanks for all for the replies to my question. My concern is using the
> K2 with V/UHF transverters, amps and preamps (some mast mounted). These
> are usually controlled with a sequencer that hard keys the radio last.
> In certain setups accidentally bumping the paddle and having the rig
> xmit could damage equipment down stream. I can use the PTT line from the
> sequencer, that would normally be used for hard keying the rig, to key a
> relay that doesn't allow CW to get to the K2 till all the up stream
> equipment is ready. However I use a foot switch and headset, that gets
> switched to three different rigs, on SSB. The footswitch is used to turn
> on the sequencers during both SSB and CW operation.. On weak signal VHF
> we often switch between SSB and CW. If I use PTT, from the sequencer, on
> SSB I haven't figured out a way to easily (automatically) disable the
> SSB PTT line on the K2 when I switch to CW. Any ideas, beside unplugging
> the mic connector or otherwise manually disabling the mic PTT line?? Is
> there some signal point inside the K2 that is active or grounded only
> during CW that could be used to possible drive a relay to disconnect the
> SSB PPT line while in CW??  Or better ideas??
>