Elecraft

K2 Muting

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R March

K2 Muting

I want to switch between a K2 and another XCVR. When I am transmitting on
the other XCVR, the K2 should be muted. Can someone enlighten me as to how
best to mute the K2 (other than keying the transmit line)? Thanks, Bob
N7UA

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S55M

Re: K2 Muting

Switch the RX of unused radio to dummy load when transmitting with the other
one.
If you want to do it "perfect" , you can use low power coax relays (cx120 or
something smaller it depends on PWR u use) or better , transfer relays.
If u use high isolation switch between the two radios and one antenna it
should be enough :)
100W is +50dBm and if u have a switch (manual or coaxial) with at least 60dB
of isolation it should not harm the other radio (-10dbm on ant port or
0,1mW).
If u r using 5W QRP even better :)

73's
Adi
S55M
9A8WW

----- Original Message -----
From: "R March" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, November 15, 2005 12:08 AM
Subject: [Elecraft] K2 Muting

> I want to switch between a K2 and another XCVR. When I am transmitting on
> the other XCVR, the K2 should be muted. Can someone enlighten me as to
how

> best to mute the K2 (other than keying the transmit line)? Thanks, Bob
> N7UA
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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S55M

Re: K2 Muting

And if u have a switch, wich shorts unused port to ground it should be even
better :)))

> Switch the RX of unused radio to dummy load when transmitting with the
other
> one.
> If you want to do it "perfect" , you can use low power coax relays (cx120
or
> something smaller it depends on PWR u use) or better , transfer relays.
> If u use high isolation switch between the two radios and one antenna it
> should be enough :)
> 100W is +50dBm and if u have a switch (manual or coaxial) with at least
60dB

> of isolation it should not harm the other radio (-10dbm on ant port or
> 0,1mW).
> If u r using 5W QRP even better :)
>
>
> 73's
> Adi
> S55M
> 9A8WW
>
>
> ----- Original Message -----
> From: "R March" <[hidden email]>
> To: <[hidden email]>
> Sent: Tuesday, November 15, 2005 12:08 AM
> Subject: [Elecraft] K2 Muting
>
>
> > I want to switch between a K2 and another XCVR. When I am transmitting

> > the other XCVR, the K2 should be muted. Can someone enlighten me as to
> how
> > best to mute the K2 (other than keying the transmit line)? Thanks, Bob
> > N7UA
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

S55M

Re: K2 Muting

Searched a bit on the net and found this:

Daiwa CS-201 two port switch has 50dB of isolation between ports on 300MHz
(HF should be better), and as stated, unused ports are grounded .

Ok, now i will stop :)

Adi

----- Original Message -----
From: "S55M" <[hidden email]>
To: "S55M" <[hidden email]>; "R March" <[hidden email]>;
<[hidden email]>
Sent: Tuesday, November 15, 2005 12:26 AM
Subject: Re: [Elecraft] K2 Muting

> And if u have a switch, wich shorts unused port to ground it should be
even
> better :)))
>
>
>
> > Switch the RX of unused radio to dummy load when transmitting with the
> other
> > one.
> > If you want to do it "perfect" , you can use low power coax relays
(cx120

> or
> > something smaller it depends on PWR u use) or better , transfer relays.
> > If u use high isolation switch between the two radios and one antenna it
> > should be enough :)
> > 100W is +50dBm and if u have a switch (manual or coaxial) with at least
> 60dB
> > of isolation it should not harm the other radio (-10dbm on ant port or
> > 0,1mW).
> > If u r using 5W QRP even better :)
> >
> >
> > 73's
> > Adi
> > S55M
> > 9A8WW
> >
> >
> > ----- Original Message -----
> > From: "R March" <[hidden email]>
> > To: <[hidden email]>
> > Sent: Tuesday, November 15, 2005 12:08 AM
> > Subject: [Elecraft] K2 Muting
> >
> >
> > > I want to switch between a K2 and another XCVR. When I am

transmitting
> on
> > > the other XCVR, the K2 should be muted. Can someone enlighten me as
to
> > how
> > > best to mute the K2 (other than keying the transmit line)? Thanks,
Bob

> > > N7UA
> > >
> > > _______________________________________________
> > > Elecraft mailing list
> > > Post to: [hidden email]
> > > You must be a subscriber to post to the list.
> > > Subscriber Info (Addr. Change, sub, unsub etc.):
> > > http://mailman.qth.net/mailman/listinfo/elecraft
> > >
> > > Help: http://mailman.qth.net/subscribers.htm
> > > Elecraft web page: http://www.elecraft.com
> > >
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
>
>

Don Wilhelm-3

RE: K2 Muting

In reply to this post by R March

Bob,

This was discussed some time back, but I can't find the details at the
moment. The essentials follow:

You can dig into the K2 and find the /MUTE line (on the Control Board) that
goes from the microprocessor to the muting FETs Q6 and Q7. Insert a series
resistor in this line (try 2.2k and experiment lower from there, using the
highest value that allows K2 to mute normally with this resistor inserted),
and bring your external muting line into the K2 such that the gates of Q6
and Q7 are grounded when you wish to mute the K2 from the external control
source (open for normal operation).

This will mute the audio - keeping RF out of the non-transmitting K2 is
another matter.

73,
Don W3FPR

> -----Original Message-----
>
> I want to switch between a K2 and another XCVR. When I am transmitting on
> the other XCVR, the K2 should be muted. Can someone enlighten me
> as to how
> best to mute the K2 (other than keying the transmit line)? Thanks, Bob
> N7UA
>
>

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Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
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S55M

Re: K2 Muting

In reply to this post by S55M

Sorry- I missed argument completely!

----- Original Message -----
From: "S55M" <[hidden email]>
To: "S55M" <[hidden email]>; "R March" <[hidden email]>;
<[hidden email]>
Sent: Tuesday, November 15, 2005 12:26 AM
Subject: Re: [Elecraft] K2 Muting

> And if u have a switch, wich shorts unused port to ground it should be
even
> better :)))
>
>
>
> > Switch the RX of unused radio to dummy load when transmitting with the
> other
> > one.
> > If you want to do it "perfect" , you can use low power coax relays
(cx120

transmitting
> on
> > > the other XCVR, the K2 should be muted. Can someone enlighten me as
to
> > how
> > > best to mute the K2 (other than keying the transmit line)? Thanks,
Bob