KPA1500 Enhancement

With no interest in SO2R, I wonder why you would want a K3 and K3S both
connected to the same amp. Regardless, keeping the amp physically small
and lightweight is a great selling point.  External antenna switches are
readily available. For me, one input and one output is perfectly fine.

John KK9A

From Wayne n6kr m
Fri Apr 28 12:35:45 EDT 2017

Hi Tom,

I don’t believe we have enough rear panel or internal space in the KPA1500
to accommodate a two-rig switch. That said, if you (or anyone else) wants
to use a home-rolled or commercial rig/antenna switch, or an SO2R box,
we’ll try to find a way to help with integration.

For example, the KPA1500’s front-panel “ANTENNA” switch has a tap function
but not a hold function. We could create a hold function that would select
between two rigs via an external relay. There are various possibilities
for control that I’ll be happy to discuss with you if you’re interested.

73,
Wayne
N6KR



> On Apr 28, 2017, at 6:45 AM, Thomas Donohue <tomdon92 at gmail.com> wrote:
>
> Hi to all:
>
> I'm changing the topic back to my original question, which has not been
answered. Are there plans or thoughts to add a second RF input to the
amp similar to the two RF inputs on the Yaesu VL1000? I'm not interested
in SO2R, I am interested in feeding my K3 and K3S into a KPA1500, much
the same as I'm currently doing with the VL1000.
>
> Best 73,
> Tom/W1QU

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[Barry Baines]

John:

> On Apr 28, 2017, at 1:44 PM, [hidden email] wrote:
>
> With no interest in SO2R, I wonder why you would want a K3 and K3S both
> connected to the same amp.


Having two radio inputs on the KPA1500 or any amplifier, particularly if the RF exciter port selection is done either 1) automatically through RF Sensing or 2) remote selection would be a very cool feature for stations that are remote operated.

I currently use the K3/KPA500/KAT500 remotely for the vast majority of my contacts because my primary residence is over 1,800 miles from my HF station.  I also have a second radio (Flex 6000 series) that I’d love to be able to connect to a remotely controlled amplifier and be select as the input once SmartSDR v2.0 is released that will provide the ability the utilize the transceiver remotely. Currently,  I don’t have an amplifier attached to the Flex that can be remoted, so my only option at the moment is to operate that transceiver ‘barefoot’.  I manage the K3 through a  K3-Mini/0 with Remote Rig 1258, the KPA500 through the Remote Rig 1216H, and the rotor (Green Heron Controller) through a second Remote Rig 1216H.

I have put down a deposit for the new PowerGenius-XL amplifier offered through FlexRadio Systems not because I plan to operate SO2R but because it will accept two exciter inputs, will allow remote configuration through LAN, and not cause problems for the amplifier.  I currently have the ability to remotely select my antennas for the K3 and Flex using 403A’s Antenna Genius 8x2 antenna switch (it has a LAN connection) that I can control through my network connection to the shack.  The Antenna Genius allows only one active RF input per antenna port, which provides some degree of protection to both transceivers.  Thus, I will eventually have two radios both connected to the same amplifier operating as needed and then use the Antenna Genius to determine which radio is connected to which antenna (Dummy load/KT-36/End Fed Half Wave).

Of course, this flexibility comes at a price— The Power Genius is significantly more expensive than the KPA1500 and uses a different architecture (e.g. two RF source inputs and two outputs to separate antenna ports which allows operation on two different bands with rapid band switching).  

Given Wayne’s comments below that there isn’t space to incorporate two RF inputs into the KPA1500, someone else may consider offering such a feature that could be integrated into the KPA1500 architecture.  However, a 3rd party product adds to station complexity and space needed on the operating desk versus having it incorporated directly into a RF amplifier.  Where high reliability is essential for remote operation where you know “it works” and the status of which radio is actually operating through the amplifier is clearly delineated, I’d be more reluctant to depend upon a 3rd party “add-on” versus having the capability built into the amplifier with the ability to properly monitor equipment status.


FWIW,

Barry Baines, WD4ASW

> Regardless, keeping the amp physically small
> and lightweight is a great selling point.  External antenna switches are
> readily available. For me, one input and one output is perfectly fine.
>
> John KK9A
>
> From Wayne n6kr m
> Fri Apr 28 12:35:45 EDT 2017
>
> Hi Tom,
>
> I don’t believe we have enough rear panel or internal space in the KPA1500
> to accommodate a two-rig switch. That said, if you (or anyone else) wants
> to use a home-rolled or commercial rig/antenna switch, or an SO2R box,
> we’ll try to find a way to help with integration.
>
> For example, the KPA1500’s front-panel “ANTENNA” switch has a tap function
> but not a hold function. We could create a hold function that would select
> between two rigs via an external relay. There are various possibilities
> for control that I’ll be happy to discuss with you if you’re interested.
>
> 73,
> Wayne
> N6KR
>
>
>
>> On Apr 28, 2017, at 6:45 AM, Thomas Donohue <tomdon92 at gmail.com> wrote:
>>
>> Hi to all:
>>
>> I'm changing the topic back to my original question, which has not been
> answered. Are there plans or thoughts to add a second RF input to the
> amp similar to the two RF inputs on the Yaesu VL1000? I'm not interested
> in SO2R, I am interested in feeding my K3 and K3S into a KPA1500, much
> the same as I'm currently doing with the VL1000.
>>
>> Best 73,
>> Tom/W1QU
>
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[Jim Brown-10]

I have one of these switches, and put it on the bench with my VNWA
vector network analyzer before installing it. Isolation is greater than
100 dB between radios for any combination of selected antennas, WITH ALL
OUTPUTS UNTERMINATED, and only the two radio ports terminated by the 50
ohm source and 50 ohm load of the VNWA.  This is a worst case condition.
Return loss is also quite low up to 6M.

The switch offers many control options, from pulls to ground or to V+ or
BCD to the far more sophisticated Antenna Genius controller, so it's
sufficiently versatile that it can be used in almost any station. I'm
controlling mine with the "pull to ground" control output of a 5B4AGN
TXBPF filter set, which gets its input from the K3 AUX out band data.
Which control logic for the 8x2 is selected by a DIP switch, and wiring
is to a 15-pin DB connector.

This is an excellent switch, and by far the best I've measured. As a
point of reference, isolation for the Array Solutions 6x2 is about -55
dB, and return loss gets unpleasantly high above 15M. The 403A 6x2 is in
the range of 75 dB isolation.

I haven't measured any other switches.

73, Jim K9YC

On Fri,4/28/2017 12:05 PM, Barry Baines wrote:
> I currently have the ability to remotely select my antennas for the K3 and Flex using 403A’s Antenna Genius 8x2 antenna switch (it has a LAN connection) that I can control through my network connection to the shack.  The Antenna Genius allows only one active RF input per antenna port, which provides some degree of protection to both transceivers.  Thus, I will eventually have two radios both connected to the same amplifier operating as needed and then use the Antenna Genius to determine which radio is connected to which antenna (Dummy load/KT-36/End Fed Half Wave).


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