Tandem operation of KPA and ACOM 1500

[Jim AB3CV]

Just a note to document what I am planning for tandem (not simultaneous)
operation of my new acquired ACOM 1500 and my trusty KPA500/KAT500 combo.
I'm strictly single op and no SO2R here so a single feedline to my remote
antenna relay.

I bought the ACOM 1500 because I felt I needed additional power at times.
It is serving that need nicely. I'm slowly getting more accustomed to the
operation of a manual tune amplifier after a few years of automated
operation of the Electraft line.

But the KPA/KAT combo is nice for instant-on and quiet idling. I usually
leave my rig on all day if I'm in the house to grab the quick DX spot. At
the first spot of the day of course I need to wait 3 minutes plus tuning
time before getting in the pileup. I find that 3+ minutes torture. The ACOM
1500 fan is also a bit annoying.

So I've decided to put the KPA/KAT back in service in the following way.

Since I have a KANT3a in my K3S I will connect the KPA/KAT to ANT1 and the
ACOM 1500 to ANT2. Selection of the ANT line from the K3S will therefore
exclusively provide RF to one or the other.

Thanks to the internal preamp of the K3S the DIGOUT1 line is freed up to
provide a signal to switch the single feedline to the antenna farm between
the KPA/KAT and ACOM 1500 outputs. I haven't yet selected a legal limit A/B
relay but there appear to be several available. A separate relay also
driven by DIGOUT1 will switch the KEY line between the amps as well.

The KPA/KAT will connect via the AUX bus as usual to provide the former
automation including setting KPA per-band power levels. I'll need to put
the KPA in Standby to go "barefoot" and I already have the barefoot level
set to an appropriate value for the ACOM 1500. The normal drive power to
the KPA is also within the range of power I already use to tune the ACOM so
no problems there if I forget to put the KPA in Standby.

Since DIGOUT1 is per-band and per-antenna the appropriate setting will be
made for each. Of course DIGOUT1 being open collector it will need to be
pulled up and appropriate buffering added to ensure safe operation of the
relay coils.

So with two button presses I can switch between the two amps and the two
ANT connections eliminates the input switching relay and wiring.

Of course if a KPA1500/KAT1500 makes a debut all of this will be replaced
in a heartbeat!!!

Comments or suggestions welcomed!

73

jim ab3cv
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[KV5J]

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[HP]

I don't see a KANT3a listed - I was hoping to get something like that with my K3 - I wanted the ANT1 ANT2 function but had no need for the tuner . Was told there was not enough market for such an animal . Too late now, ended up buying a KAT3 to get the function , figured a K3 with tuner more appealing to many . I have same sort of deal -- KAT500/KPA500 until going gets rough - ANT2 gets the Alpha brick on key amp . ????? Hank K7HP ----- Original Message -----
> The KANT3a was a great add-on for those that don't want or need the
> internal
> tuner.
> Happy to have grabbed one.
> Keith, KV5J
> --
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[Jim AB3CV]

Typo on my part.

It's a KAT3a.

jim ab3cv

On Wed, Jan 11, 2017 at 4:58 PM, HankP <[hidden email]> wrote:

> I don't see a KANT3a listed - I was hoping to get something like that with
> my K3 - I wanted the ANT1 ANT2 function but had no need for the tuner . Was
> told there was not enough market for such an animal . Too late now, ended
> up buying a KAT3 to get the function , figured a K3 with tuner more
> appealing to many . I have same sort of deal -- KAT500/KPA500 until going
> gets rough - ANT2 gets the Alpha brick on key amp . ????? Hank K7HP -----
> Original Message -----
> > The KANT3a was a great add-on for those that don't want or need the
> > internal
> > tuner.
> > Happy to have grabbed one.
> > Keith, KV5J
> > --
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>

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[Rick Tavan-2]

That's similar to what I do when operating one K3 remotely. I use a Six Pak
driven by a pair of ACC-driven band decoders for antenna switching between
the two amps because it's there already, used for SO2R antenna switching
when I'm physically at the station. That would be overkill for you - as you
say, you just need a SPDT RF relay like the ancient Dow-Key's we used to
use for T-R switching in the 60's. You could even buy a Six Pak replacement
part open frame relay from WX0B and mount it in a mini-box with some
SO-239s, very inexpensive. If I were you, I'd use a simple SPST switch
instead of programming the many combinations of DIGOUT1.

I run Key Out from the K3 to the Alpha 87A and key the KPA500 through the
ACC cable. If I neglect to put the KPA in STBY when using the Alpha, it
keys in parallel but has no drive. No extra relay, no problem. You could
also key both amps concurrently with the K3 Key Out line and a Y-splitter.

Have fun!

/Rick N6XI

On Wed, Jan 11, 2017 at 7:39 AM, Jim Miller <[hidden email]> wrote:

> Just a note to document what I am planning for tandem (not simultaneous)
> operation of my new acquired ACOM 1500 and my trusty KPA500/KAT500 combo.
> I'm strictly single op and no SO2R here so a single feedline to my remote
> antenna relay.
>
> I bought the ACOM 1500 because I felt I needed additional power at times.
> It is serving that need nicely. I'm slowly getting more accustomed to the
> operation of a manual tune amplifier after a few years of automated
> operation of the Electraft line.
>
> But the KPA/KAT combo is nice for instant-on and quiet idling. I usually
> leave my rig on all day if I'm in the house to grab the quick DX spot. At
> the first spot of the day of course I need to wait 3 minutes plus tuning
> time before getting in the pileup. I find that 3+ minutes torture. The ACOM
> 1500 fan is also a bit annoying.
>
> So I've decided to put the KPA/KAT back in service in the following way.
>
> Since I have a KANT3a in my K3S I will connect the KPA/KAT to ANT1 and the
> ACOM 1500 to ANT2. Selection of the ANT line from the K3S will therefore
> exclusively provide RF to one or the other.
>
> Thanks to the internal preamp of the K3S the DIGOUT1 line is freed up to
> provide a signal to switch the single feedline to the antenna farm between
> the KPA/KAT and ACOM 1500 outputs. I haven't yet selected a legal limit A/B
> relay but there appear to be several available. A separate relay also
> driven by DIGOUT1 will switch the KEY line between the amps as well.
>
> The KPA/KAT will connect via the AUX bus as usual to provide the former
> automation including setting KPA per-band power levels. I'll need to put
> the KPA in Standby to go "barefoot" and I already have the barefoot level
> set to an appropriate value for the ACOM 1500. The normal drive power to
> the KPA is also within the range of power I already use to tune the ACOM so
> no problems there if I forget to put the KPA in Standby.
>
> Since DIGOUT1 is per-band and per-antenna the appropriate setting will be
> made for each. Of course DIGOUT1 being open collector it will need to be
> pulled up and appropriate buffering added to ensure safe operation of the
> relay coils.
>
> So with two button presses I can switch between the two amps and the two
> ANT connections eliminates the input switching relay and wiring.
>
> Of course if a KPA1500/KAT1500 makes a debut all of this will be replaced
> in a heartbeat!!!
>
> Comments or suggestions welcomed!
>
> 73
>
> jim ab3cv
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

--

Rick Tavan
Truckee, CA
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