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K2 / XV50 interfacing to power amplifier?

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w2bvh

K2 / XV50 interfacing to power amplifier?

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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Oliver Dröse

Re: K2 / XV50 interfacing to power amplifier?

Lenny,

use a sequencer to avoid hot switching (sequencer puts the amp online first,
afterwards the transverter, then the K2, with delays between switching
stages). A quick Google search on "ptt sequencer" will provide a few good
solutions (including my own ;-)).

73, Olli - DH8BQA
http://www.dh8bqa.de

----- Original Message -----
From: "w2bvh" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, January 14, 2012 12:50 AM
Subject: [Elecraft] K2 / XV50 interfacing to power amplifier?

> 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
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
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>

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Don Wilhelm-4

Re: K2 / XV50 interfacing to power amplifier?

In reply to this post by w2bvh

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
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

w2bvh

Re: K2 / XV50 interfacing to power amplifier?

Thanks for your reply and explanation of your "footswitch mod" circuit
Don. It makes perfect sense now that you've elaborated on the
functionality. And I can see how putting a properly wired sequencer
between a foot switch and the "footswitch mod's" PTT input would protect
my amp.

I simply misunderstood the function of your mod. I thought the
"footswitch mod" activates the K2 and/or XV50 keyline without producing
rf. Based on that (wrong) assumption, I expected the XV50 "Key Out"
port to enable my amplifier after I pressed the foot switch.

I'll build up a sequencer and wire it in.

Tnx & 73,
Lenny W2BVH

On 1/13/2012 7:43 PM, Don Wilhelm wrote:

> 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
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>

KD7PY

Re: K2 / XV50 interfacing to power amplifier?

In reply to this post by w2bvh

Here is what I use to key my 8877 amp with the XV50

http://www.w6pql.com/relay_sequencer.htm

Ed K7WIA