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DIGOUT1 to switch K3's key out to two separate amps based on band (HF or 6m)

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W7VH

DIGOUT1 to switch K3's key out to two separate amps based on band (HF or 6m)

I'd like to use DIGOUT1
to switch the K3's key out between two amps based on band
(HF and 6m). I'm not that technical and am not used to designing
little transistor switching circuits and wondered if you can give
me some info on how to do it. I guess I'd need a transistor that
would switch based on the DIGOUT1 voltage and could handle the
power needed to switch a reed relay to key the separate amps.

If you have any info that could help, I'd appreciate it.

Thanks,

Jon

Don Wilhelm-4

Re: DIGOUT1 to switch K3's key out to two separate amps based on band (HF or 6m)

Jon,

I would use a 2N7000. The circuit could be quite easy - a 10k resistor
from +12 volts (K3 +12 volts out will do fine) - the source goes to
ground - the drain connects to the relay coil. I would strongly
recommend a diode (1N400x) between the drain and ground (cathode toward
the drain). The other side of the relay connects to a voltage source
that matches the relay coil rating (I would suggest a 12 volt relay just
because it is easier).

If you use a SPDT relay, you can connect the common to the K3 KEYOUT and
the NO and NC contacts each go to their own amplifier.

Set CONFIG menu DIGIOUT1 to OFF for all bands and antennas that you want
the relay to be activated, and to ON for all bands and antennas that you
do *not* activate the relay. There are no "don't care" settings.

Because of the lack of "don't care" states, you may be better off
decoding 6 meters from the band data outputs - a logical AND of BAND3
and BAND1 will do because those two bits will only be active for 6
meters (You don't have to set things correctly for the other bands).
Follow a NAND with an inverter (another two input NAND with both inputs
tied together) and that drives the 2N7000 - omit the resistor from the
gate to +12 volts if you do it that way, the drain and source
connections to the 2N7000 are unchanged. A single CD4011 will do with 2
gates left over and will operate on a 12 volt supply.

73,
Don W3FPR

73,
Don W3FPR

W7VH wrote:

> I'd like to use DIGOUT1
> to switch the K3's key out between two amps based on band
> (HF and 6m). I'm not that technical and am not used to designing
> little transistor switching circuits and wondered if you can give
> me some info on how to do it. I guess I'd need a transistor that
> would switch based on the DIGOUT1 voltage and could handle the
> power needed to switch a reed relay to key the separate amps.
>
> If you have any info that could help, I'd appreciate it.
>
> Thanks,
>
> Jon
>

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Don Wilhelm-4

Re: DIGOUT1 to switch K3's key out to two separate amps based on band (HF or 6m)

In reply to this post by W7VH

Jon and all,

Tom W8JI caught a problem in my circuit description. The diode across
the transistor will do nothing. Put the diode across the relay coil.
The cathode still goes to the end where the drain connects.

73,
Don W3FPR
--------------------------------------------------------------------------

Jon,

I would use a 2N7000. The circuit could be quite easy - a 10k resistor
from +12 volts (K3 +12 volts out will do fine) - the source goes to
ground - the drain connects to the relay coil. I would strongly
recommend a diode (1N400x) between the drain and ground (cathode toward
the drain). The other side of the relay connects to a voltage source
that matches the relay coil rating (I would suggest a 12 volt relay just
because it is easier).

If you use a SPDT relay, you can connect the common to the K3 KEYOUT and
the NO and NC contacts each go to their own amplifier.

Set CONFIG menu DIGIOUT1 to OFF for all bands and antennas that you want
the relay to be activated, and to ON for all bands and antennas that you
do *not* activate the relay. There are no "don't care" settings.

Because of the lack of "don't care" states, you may be better off
decoding 6 meters from the band data outputs - a logical AND of BAND3
and BAND1 will do because those two bits will only be active for 6
meters (You don't have to set things correctly for the other bands).
Follow a NAND with an inverter (another two input NAND with both inputs
tied together) and that drives the 2N7000 - omit the resistor from the
gate to +12 volts if you do it that way, the drain and source
connections to the 2N7000 are unchanged. A single CD4011 will do with 2
gates left over and will operate on a 12 volt supply.

73,
Don W3FPR

73,
Don W3FPR

W7VH wrote:

Don Wilhelm-4

Re: DIGOUT1 to switch K3's key out to two separate amps based on band (HF or 6m)

OK all,

Tom again caught a problem with my description. The cathode of the
diode goes to the end of the relay coil where the + voltage connects and
the *anode* connects to the other end of the relay and the drain of the
2N7000.

Thanks for catching that Tom. He sent a private note to me, and I gave
him permission to post it on the reflector, but being the gentleman he
is, he did not see fit to do that.

Anyway, now if someone tries to duplicate that circuit, you know the
proper way to connect the diode.

73,
Don W3FPR

Don Wilhelm wrote:

> Jon and all,
>
> Tom W8JI caught a problem in my circuit description. The diode across
> the transistor will do nothing. Put the diode across the relay coil.
> The cathode still goes to the end where the drain connects.
>
> 73,
> Don W3FPR
> --------------------------------------------------------------------------
>
>
> Jon,
>
> I would use a 2N7000. The circuit could be quite easy - a 10k resistor
> from +12 volts (K3 +12 volts out will do fine) - the source goes to
> ground - the drain connects to the relay coil. I would strongly
> recommend a diode (1N400x) between the drain and ground (cathode toward
> the drain). The other side of the relay connects to a voltage source
> that matches the relay coil rating (I would suggest a 12 volt relay just
> because it is easier).
>
> If you use a SPDT relay, you can connect the common to the K3 KEYOUT and
> the NO and NC contacts each go to their own amplifier.
>
> Set CONFIG menu DIGIOUT1 to OFF for all bands and antennas that you want
> the relay to be activated, and to ON for all bands and antennas that you
> do *not* activate the relay. There are no "don't care" settings.
>
> Because of the lack of "don't care" states, you may be better off
> decoding 6 meters from the band data outputs - a logical AND of BAND3
> and BAND1 will do because those two bits will only be active for 6
> meters (You don't have to set things correctly for the other bands).
> Follow a NAND with an inverter (another two input NAND with both inputs
> tied together) and that drives the 2N7000 - omit the resistor from the
> gate to +12 volts if you do it that way, the drain and source
> connections to the 2N7000 are unchanged. A single CD4011 will do with 2
> gates left over and will operate on a 12 volt supply.
>
> 73,
> Don W3FPR
>
> 73,
> Don W3FPR
>
> W7VH wrote:
>> I'd like to use DIGOUT1
>> to switch the K3's key out between two amps based on band
>> (HF and 6m). I'm not that technical and am not used to designing
>> little transistor switching circuits and wondered if you can give
>> me some info on how to do it. I guess I'd need a transistor that
>> would switch based on the DIGOUT1 voltage and could handle the
>> power needed to switch a reed relay to key the separate amps.
>>
>> If you have any info that could help, I'd appreciate it.
>>
>> Thanks,
>>
>> Jon
>>
>
>