[Elecraft] K2 / XV50 interfacing to power amplifier?

[Don Wilhelm]

Lenny,

The W3FPR "footswitch" mod should work with the XV50 just like it does 
with the base K2.
The K2 cannot be keyed until the "PTT" line to the W3FPR circuit is closed.
The XV50 will be keyed as normal by the K2 firmware through the cable 
between the K2 and the XV50.  You should have NO connection to the XV50 
Keyin line.

Maybe your calling my circuit the "footswitch" mod is your problem - it 
is really PTT for CW, and will do the job if it is connected correctly 
into the system.  You need to have a sequencer. The footswitch (or 
whatever other switch you choose) starts the sequencer chain - the first 
output from the sequencer isolates any preamps, the second output 
activates the amplifier, and the third output goes to my circuit to make 
its "PTT IN" input active.
That last action will then allow a dot or dash key closure into the K2 - 
the K2 in turn will activate the XV50.

If your problem is on SSB rather than CW, and you use the PTT line in 
the mmic jack,  you may need to make one additional change to the K2 - 
open the PTT line before it gets to the SSB board.  You can normally 
just not put the PTT jumper on the mic configuration header, and then 
run a wire between the mic jack PTT pin to the DOT input of my W3FPR CW 
PTT circuit.

73,
Don W3FPR

On 1/13/2012 6:50 PM, w2bvh wrote:
> HI!
>
> If you have a K2 / XV50 combo and have interfaced it to a power
> amplifier I'd like to hear from you on how you did it and what pitfalls
> you might have encountered.
>
> I've got a 6 Meter KW amp that I'd like to hook up to the K2 /XV50 and
> I'm concerned about possibly hot switching the RF on the output side of
> the amp with its 25 mS rf relay. The amp is switched active by grounding
> its keyline input.
>
> According to Elecraft, RF is only delayed by 3 mS from when the rig is
> keyed and as stated above, my amplifier output relay takes 25 mS to switch.
>
> I tried adding the W3FPR footswitch mod to the K2 hoping it would do the
> trick.  It works  just fine when the K2 is set for any of the HF bands,
> but it doesn't seem to have any effect when using 6 Meters. Its possible
> that I implemented it wrong, but I don't think so because it does work
> OK without the XV50.
>
> Ideally I'd like to have a set-up where the K2, XV50 and amplifier could
> be thought of as just a single high power transceiver whose band switch
> has been set to 6 Meters.
>
> Any experience you've had doing a setup with the K2, XV50 and a power
> amp would be very much appreciated.
>
> 73
> Lenny W2BVH
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