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KPA1500 ATU - ability to handle more than two antennas

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john@kk9a.com

KPA1500 ATU - ability to handle more than two antennas

I use the band data from my K3S's to select the appropriate antenna and
bandpass filters.

John KK9A

Dan AE9K dan at ae9k.com
Thu Jan 25 14:48:50 EST 2018

While I'm awaiting the delivery of my KPA1500 I'm wondering if/how the amp's
ATU can accommodate more than two antennas. For example, if I have an
antenna switch connected to one of the amp's antenna jacks is there a
facility on the amp that would allow me to choose one of two /logical/
antennas beyond the ANT1 / ANT2 physical selection? Having two sets of
memories per band per physical port would accommodate 4 antennas.

Does the KPA1500 support this or something similar to allow for more than
two antennas? If not, this seems pretty simple to implement as a firmware
change - assuming there's enough memory available. If memory is a
constraint I suppose you could provide the option to halve the number of
tuning solutions stored per segment to keep the memory footprint the same.

Thanks,

Dan
AE9K

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Ignacy

Re: KPA1500 ATU - ability to handle more than two antennas

Multiple (4 to 6) antenna connectors is a nice feature of Expert amps. Once
you have antenna matched, QSY to up to 2-3 antennas per band is automatic.
The psychological effect is astounding, as trying to get SWR as close to 1:1
is becoming a waste of time. In my Expert 2k-fa I have 5 antennas connected.

Having two antenna connectors is probably enough for heavy duty contesters
where sophisticated antenna selection together with SO2R is done
externally.

However, Elecraft can provide several logical antennas software selected,
with each one matched separately. They can also come with an external
switch.

Only 2 connectors is a reason why I am not placing the order for KPA1500.

Ignacy, NO9E

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K9MA

Re: KPA1500 ATU - ability to handle more than two antennas

I'm concerned about the same issue: Multiple antennas on one band. I
have an automated antenna selection system. In addition to following
the band data from the transceiver, there are switches to select
antennas. I frequently have to very quickly switch antennas, so it must
involve only a single switch. Using a mouse with the computer is
nowhere near fast enough and I really don't want to make it dependent on
the computer, anyhway. However, my antennas have different impedances,
so require different ATU settings. So, how can I tie the KPA1500 ATU
into my antenna control switch so it automatically switches settings?
All the antenna switching is external to the amp, so only a single amp
output is used. The ideal would be a control line to the amp,
controlled by the same switch that selects antennas, which would select
ATU settings. I really don't want to make it dependent on the
computer. I expect others have the same issue. Can the KPA1500 be made
to do something like this?

73,
Scott K9MA

--
Scott K9MA

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Ignacy

Re: KPA1500 ATU - ability to handle more than two antennas

If there are only two antennas per band, perhaps this is doable with
dual-input antenna switch (like DXE-RR2X8B) and Microham StationMaster. For
each band, MH SM selects one antenna for A and another one for B. To change
an antenna within a band, select A or B in the amp or via CAT.

Ignacy, NO9E

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wayne burdick

Re: KPA1500 ATU - ability to handle more than two antennas

Administrator

In reply to this post by K9MA

This is definitely doable from the amp. All it takes is an external antenna switch with a control port compatible with RS232, Ethernet, USB, or one of the amp’s multi-purpose digital output lines. (These have other uses, too, such as SWR alarm output.)

To select among antennas from the amp, you could do any of the following:

- tap the ANT switch to go between two or more antennas in rotation

- tap ANT then use the UP/DN switches

- assign two frequently-used antennas to the front-panel PF1 and PF2 switches

In all cases, the LCD would show your selection from among N external antenna jacks.

We can adapt the firmware to handle any such scenario.

Wayne
N6KR

> On Jan 25, 2018, at 7:58 PM, K9MA <[hidden email]> wrote:
>
> I'm concerned about the same issue: Multiple antennas on one band. I have an automated antenna selection system. In addition to following the band data from the transceiver, there are switches to select antennas. I frequently have to very quickly switch antennas, so it must involve only a single switch. Using a mouse with the computer is nowhere near fast enough and I really don't want to make it dependent on the computer, anyhway. However, my antennas have different impedances, so require different ATU settings. So, how can I tie the KPA1500 ATU into my antenna control switch so it automatically switches settings? All the antenna switching is external to the amp, so only a single amp output is used. The ideal would be a control line to the amp, controlled by the same switch that selects antennas, which would select ATU settings. I really don't want to make it dependent on the computer. I expect others have the same issue. Can the KPA1500 be made to do something like this?
>
> 73,
> Scott K9MA
>
> --
> Scott K9MA
>
> [hidden email]
>
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K9MA

Re: KPA1500 ATU - ability to handle more than two antennas

How about using an external switch to select which ATU settings the amp
uses? Perhaps with a digital INPUT line?

Scott K9MA

On 1/26/2018 11:15, Wayne Burdick wrote:

> This is definitely doable from the amp. All it takes is an external antenna switch with a control port compatible with RS232, Ethernet, USB, or one of the amp’s multi-purpose digital output lines. (These have other uses, too, such as SWR alarm output.)
>
> To select among antennas from the amp, you could do any of the following:
>
> - tap the ANT switch to go between two or more antennas in rotation
>
> - tap ANT then use the UP/DN switches
>
> - assign two frequently-used antennas to the front-panel PF1 and PF2 switches
>
> In all cases, the LCD would show your selection from among N external antenna jacks.
>
> We can adapt the firmware to handle any such scenario.
>
> Wayne
> N6KR
>
>
>> On Jan 25, 2018, at 7:58 PM, K9MA <[hidden email]> wrote:
>>
>> I'm concerned about the same issue: Multiple antennas on one band. I have an automated antenna selection system. In addition to following the band data from the transceiver, there are switches to select antennas. I frequently have to very quickly switch antennas, so it must involve only a single switch. Using a mouse with the computer is nowhere near fast enough and I really don't want to make it dependent on the computer, anyhway. However, my antennas have different impedances, so require different ATU settings. So, how can I tie the KPA1500 ATU into my antenna control switch so it automatically switches settings? All the antenna switching is external to the amp, so only a single amp output is used. The ideal would be a control line to the amp, controlled by the same switch that selects antennas, which would select ATU settings. I really don't want to make it dependent on the computer. I expect others have the same issue. Can the KPA1500 be made to do something like this?
>>
>> 73,
>> Scott K9MA
>>
>> --
>> Scott K9MA
>>
>> [hidden email]
>>
>> ______________________________________________________________
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Scott K9MA

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Matt Murphy

Re: KPA1500 ATU - ability to handle more than two antennas

I think this is a very important aspect of station design and a big
consideration for any future amp purchase I make.

I'd like to respectfully suggest that Elecraft consider designing a
bulletproof 16x2 antenna switch rated for 5KW and 10:1 SWR (and lots of
isolation between ports) that integrates seamlessly with the amp and
tuner.

There is typically a need to switch both antennas and high power bandpass
filters, or at least the high cost of high power bandpass filters makes
using only one for each band (via switching) very useful.

So when the amp QSYs to 40m the ideal scenario allows the switching in of a
40m bandpass filter after the amp, and then whichever antennas are usable
on 40m, with the tuner knowing which antenna was chosen so that it can
switch to the previously known settings for instant TX.

73,
Matt NQ6N

On Fri, Jan 26, 2018 at 1:45 PM, K9MA <[hidden email]> wrote:

> How about using an external switch to select which ATU settings the amp
> uses? Perhaps with a digital INPUT line?
>
> Scott K9MA
>
>
> On 1/26/2018 11:15, Wayne Burdick wrote:
>
>> This is definitely doable from the amp. All it takes is an external
>> antenna switch with a control port compatible with RS232, Ethernet, USB, or
>> one of the amp’s multi-purpose digital output lines. (These have other
>> uses, too, such as SWR alarm output.)
>>
>> To select among antennas from the amp, you could do any of the following:
>>
>> - tap the ANT switch to go between two or more antennas in rotation
>>
>> - tap ANT then use the UP/DN switches
>>
>> - assign two frequently-used antennas to the front-panel PF1 and PF2
>> switches
>>
>> In all cases, the LCD would show your selection from among N external
>> antenna jacks.
>>
>> We can adapt the firmware to handle any such scenario.
>>
>> Wayne
>> N6KR
>>
>>
>> On Jan 25, 2018, at 7:58 PM, K9MA <[hidden email]> wrote:
>>>
>>> I'm concerned about the same issue: Multiple antennas on one band. I
>>> have an automated antenna selection system. In addition to following the
>>> band data from the transceiver, there are switches to select antennas. I
>>> frequently have to very quickly switch antennas, so it must involve only a
>>> single switch. Using a mouse with the computer is nowhere near fast enough
>>> and I really don't want to make it dependent on the computer, anyhway.
>>> However, my antennas have different impedances, so require different ATU
>>> settings. So, how can I tie the KPA1500 ATU into my antenna control switch
>>> so it automatically switches settings? All the antenna switching is
>>> external to the amp, so only a single amp output is used. The ideal would
>>> be a control line to the amp, controlled by the same switch that selects
>>> antennas, which would select ATU settings. I really don't want to make it
>>> dependent on the computer. I expect others have the same issue. Can the
>>> KPA1500 be made to do something like this?
>>>
>>> 73,
>>> Scott K9MA
>>>
>>> --
>>> Scott K9MA
>>>
>>> [hidden email]
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>
> --
> Scott K9MA
>
> [hidden email]
>
>
> ______________________________________________________________
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K9MA

Re: KPA1500 ATU - ability to handle more than two antennas

I don't think it's desirable to have the amplifier controls external
antenna relays. One might sometimes want to operate barefoot. Besides,
there are external antenna relay boxes available, as well as
programmable controllers. (And a few of us dinosaurs are using homebrew
antenna controllers.) In any case, an external controller can easily be
made to switch antenna relays, bandpass filters, etc. Another advantage
of doing all the antenna switching external to the amplifier is it
allows using a single coax, which can easily be disconnected when
there's lightning about.

If one already has the antenna switching and control set up, the ONLY
new thing the amplifier has to do is to be able to switch the ATU among
2 or more sets of parameters for each band, and have some way the
external control system can tell the amplifier which set to use. My
preference would be some logic inputs to the amplifier, say 3 bits,
which would allow 8 sets of parameters for each band. (That might be
excessive, but maybe not for some of the big muli-multi stations. I'd
settle for 2 bits, or even 1.) Using a serial port forces the user to
use either a computer or a controller with a serial port, not compatible
with simple homebrew systems.

My system, for example, has a toggle switch to select one of my two
tribanders. I can switch back and forth several times in a second when
trying to determine which direction the signal is coming from. I can't
possibly manipulate more than one switch that fast, nor to I want to
have to reach over to wherever the amplifier happens to be, and I
certainly don't want to be messing around with a mouse. (While all this
antenna switching is going on, the other hand is running the radio.)

73,
Scott K9MA

On 1/26/2018 16:25, Matt NQ6N wrote:

> I think this is a very important aspect of station design and a big
> consideration for any future amp purchase I make.
>
> I'd like to respectfully suggest that Elecraft consider designing a
> bulletproof 16x2 antenna switch rated for 5KW and 10:1 SWR (and lots
> of isolation between ports) that integrates seamlessly with the amp
> and tuner.
>
> There is typically a need to switch both antennas and high power
> bandpass filters, or at least the high cost of high power bandpass
> filters makes using only one for each band (via switching) very useful.
>
> So when the amp QSYs to 40m the ideal scenario allows the switching in
> of a 40m bandpass filter after the amp, and then whichever antennas
> are usable on 40m, with the tuner knowing which antenna was chosen so
> that it can switch to the previously known settings for instant TX.
>
> 73,
> Matt NQ6N
>
>
>
> On Fri, Jan 26, 2018 at 1:45 PM, K9MA <[hidden email]
> <mailto:[hidden email]>> wrote:
>
> How about using an external switch to select which ATU settings
> the amp uses? Perhaps with a digital INPUT line?
>
> Scott K9MA
>
>
> On 1/26/2018 11:15, Wayne Burdick wrote:
>
> This is definitely doable from the amp. All it takes is an
> external antenna switch with a control port compatible with
> RS232, Ethernet, USB, or one of the amp’s multi-purpose
> digital output lines. (These have other uses, too, such as SWR
> alarm output.)
>
> To select among antennas from the amp, you could do any of the
> following:
>
> - tap the ANT switch to go between two or more antennas in
> rotation
>
> - tap ANT then use the UP/DN switches
>
> - assign two frequently-used antennas to the front-panel PF1
> and PF2 switches
>
> In all cases, the LCD would show your selection from among N
> external antenna jacks.
>
> We can adapt the firmware to handle any such scenario.
>
> Wayne
> N6KR
>
>
> On Jan 25, 2018, at 7:58 PM, K9MA <[hidden email]
> <mailto:[hidden email]>> wrote:
>
> I'm concerned about the same issue: Multiple antennas on
> one band. I have an automated antenna selection system.
> In addition to following the band data from the
> transceiver, there are switches to select antennas. I
> frequently have to very quickly switch antennas, so it
> must involve only a single switch. Using a mouse with the
> computer is nowhere near fast enough and I really don't
> want to make it dependent on the computer, anyhway.
> However, my antennas have different impedances, so require
> different ATU settings. So, how can I tie the KPA1500 ATU
> into my antenna control switch so it automatically
> switches settings? All the antenna switching is external
> to the amp, so only a single amp output is used. The
> ideal would be a control line to the amp, controlled by
> the same switch that selects antennas, which would select
> ATU settings. I really don't want to make it dependent on
> the computer. I expect others have the same issue. Can
> the KPA1500 be made to do something like this?
>
> 73,
> Scott K9MA
>
> --
> Scott K9MA
>
> [hidden email] <mailto:[hidden email]>
>
>
>

Bill Frantz

Re: KPA1500 ATU - ability to handle more than two antennas

My switch uses an Arduino to read the band lines from the K3 and
select the last antenna(s) used on that band. It the code could
easily be modified to tell an antenna tuner -- in the K3, an
amp, or separate -- which antenna system is in use. Manual
switching is with a button for each antenna.

73 Bill AE6JV

On 1/27/18 at 11:31 PM, [hidden email] (K9MA) wrote:

>Another advantage of doing all the antenna switching external
>to the amplifier is it allows using a single coax, which can
>easily be disconnected when there's lightning about.

In my case, it minimizes the number of coax runs, which keeps my
wife happy.

>My system, for example, has a toggle switch to select one of my
>two tribanders. I can switch back and forth several times in
>a second when trying to determine which direction the signal is
>coming from. I can't possibly manipulate more than one switch
>that fast, nor to I want to have to reach over to wherever the
>amplifier happens to be, and I certainly don't want to be
>messing around with a mouse. (While all this antenna
>switching is going on, the other hand is running the radio.)

-----------------------------------------------------------------------
Bill Frantz | I don't have high-speed | Periwinkle
(408)356-8506 | internet. I have DSL. | 16345
Englewood Ave
www.pwpconsult.com | | Los Gatos,
CA 95032

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K9MA

Re: KPA1500 ATU - ability to handle more than two antennas

I designed my station controller over 20 years ago. Since I'm a
hardware designer, it's all hardware. I suppose, however, something like
your Arduino could be programmed to read the antenna switch and send a
serial command to the amplifier, though that seems a lot of trouble.

73,
Scott K9MA

On 1/27/2018 10:06, Bill Frantz wrote:

> My switch uses an Arduino to read the band lines from the K3 and
> select the last antenna(s) used on that band. It the code could easily
> be modified to tell an antenna tuner -- in the K3, an amp, or separate
> -- which antenna system is in use. Manual switching is with a button
> for each antenna.
>
> 73 Bill AE6JV
>
> On 1/27/18 at 11:31 PM, [hidden email] (K9MA) wrote:
>
>> Another advantage of doing all the antenna switching external to the
>> amplifier is it allows using a single coax, which can easily be
>> disconnected when there's lightning about.
>
> In my case, it minimizes the number of coax runs, which keeps my wife
> happy.
>
>
>> My system, for example, has a toggle switch to select one of my two
>> tribanders. I can switch back and forth several times in a second
>> when trying to determine which direction the signal is coming from.
>> I can't possibly manipulate more than one switch that fast, nor to I
>> want to have to reach over to wherever the amplifier happens to be,
>> and I certainly don't want to be messing around with a mouse. (While
>> all this antenna switching is going on, the other hand is running the
>> radio.)
>
> -----------------------------------------------------------------------
> B

Ignacy

Re: KPA1500 ATU - ability to handle more than two antennas

Microham Station Master listens to K3 traffic, decodes frequency and sets
switches as programmed. This is regardless whether the amp or computer are
on. Also very reliable unit. Can also be used for as rotator controller. I
cannot praise it enough.

I have Expert 2k-fa and it is a love-hate relationships. On one hand, 2
input and 6 outputs with a reasonable antenna tuner. I switch bands and
antennas, and no extra work. On the other hand, it failed 4 times, the PS
supply creates RFI (fixed partially by a large toroid), and it is pretty
loud., requiring headsets all the time. Also, ability to control antennas
outside of front panel (or an unreliable app) is variable under Flex only
(DDUTIL).

Expert 1.3k-fa has RFI quiet PS and is very light. Its back fans are quiet
but the one insides is annoyingly loud - apparently fixed in newer models.
Also only 4 antenna outputs. But it was brilliant working with KX3 as
CE0Y/NO9E.

So I am looking for an Expert replacement -quiet both acoustically and RFI,
as automatic and with good CAT. Perhaps KPA1500-2 will be it.

Ignacy, NO9E

--
Sent from: http://elecraft.365791.n2.nabble.com/
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K9MA

Re: KPA1500 ATU - ability to handle more than two antennas

I considered buying the Expert 2K, but decided against it because there
was no apparent way to tie the ATU into my antenna switch. I'm not sure
there is or will be with the KPA1500, either, but it is much more
attractive based on Elecraft's reputation. Besides, I've since built an
external tuner, which IS tied into my antenna switch, which matches both
tribanders almost perfectly, so it won't even be necessary to use the
ATU. That was, however, a lot of work.

73,
Scott K9MA

On 1/27/2018 12:06, Ignacy wrote:

> Microham Station Master listens to K3 traffic, decodes frequency and sets
> switches as programmed. This is regardless whether the amp or computer are
> on. Also very reliable unit. Can also be used for as rotator controller. I
> cannot praise it enough.
>
> I have Expert 2k-fa and it is a love-hate relationships. On one hand, 2
> input and 6 outputs with a reasonable antenna tuner. I switch bands and
> antennas, and no extra work. On the other hand, it failed 4 times, the PS
> supply creates RFI (fixed partially by a large toroid), and it is pretty
> loud., requiring headsets all the time. Also, ability to control antennas
> outside of front panel (or an unreliable app) is variable under Flex only
> (DDUTIL).
>
> Expert 1.3k-fa has RFI quiet PS and is very light. Its back fans are quiet
> but the one insides is annoyingly loud - apparently fixed in newer models.
> Also only 4 antenna outputs. But it was brilliant working with KX3 as
> CE0Y/NO9E.
>
> So I am looking for an Expert replacement -quiet both acoustically and RFI,
> as automatic and with good CAT. Perhaps KPA1500-2 will be it.
>
> Ignacy, NO9E
>
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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]