KXPA100: Manual antenna switching and output power limit questions

[KC2LST]

Hi All,

I searched Nabble and did not find these questions about the KXPA100 answered, so apologies in advance if they have been asked/answered previously.

1. If one has the KXAT100 ATU option installed, and is using the KXPA100 with an exciter other than the KX3 <gasp>, is manual antenna switching accomplished with a long press of the ATU TUNE button, as appears to be so from the legend on the control panel, or some other way?

(Full disclosure: I have an IC-703+ with the W4RT dual Collins filter kit installed that unfortunately I get to use seldom enough that I can't justify replacing with a KX3 at this time.)

2. Does the KXPA100 have any limitation on recommended power output when using high duty cycle digital modes such as RTTY, JT65, PSK?

Thanks in advance and 73 de Tyler, KC2LST



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[Lyle Johnson]

My unofficial response is that this is a thermal issue.  With adequate
cooling (operating on top of a glacier in Alaska in January), it can run
at 100W for a very long time.  In a bad thermal environment (operating
in an olive drab canvas tent near Yuma at 1 PM local time in late June
with a paperback book or two stacked on top of the heatsink), it will
protect itself and go offline if it gets too hot.

73,

Lyle KK7P

  2. Does the KXPA100 have any limitation on recommended power output when using high duty cycle digital modes such as RTTY, JT65, PSK?


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[Paul Saffren N6HZ]

Hi Tyler,

Basically what Lyle said about power output vs ambient temperature.  

Regarding the antenna switching, long press on the TUNE button changes antennas. You'll  also be able to configure the amp to select a pre-programmed antenna port based on band.  For example, a 6 meter beam on ANT2 and a dipole on ANT1 etc.  This will be configurable using the KXPA Utility.

73,

Paul

[Jim Brown-10]

On 6/20/2013 12:02 PM, [hidden email] wrote:
> I have an IC-703+ with the W4RT dual Collins filter kit installed that unfortunately I get to use seldom enough that I can't justify replacing with a KX3 at this time.)

You might want to re-think that, depending on what other radios you
own.  The KX3 with a 100W amp is a world class 100W radio, as good as
anything you can buy for for less than $10K.  Also, I suspect that the
IC703 isn't very clean with respect to phase noise and TX IM products
(check ARRL reviews), so it may not be clean enough to drive an amp to
100W. That could result in some pretty unhappy ham neighbors.

So just because you can doesn't mean that you should. :)

If it was me, I'd sell the 703 and buy the KX3.

73, Jim K9YC
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[KC2LST]

Thanks Lyle, Paul and Jim for your replies.

On 6/20/2013 5:49 PM, K9YC wrote:

> You might want to re-think that, depending on what other radios you
own.  The KX3 with a 100W amp is a world class 100W radio, as good as
anything you can buy for for less than $10K.  Also, I suspect that the
IC703 isn't very clean with respect to phase noise and TX IM products
(check ARRL reviews), so it may not be clean enough to drive an amp to
100W. That could result in some pretty unhappy ham neighbors.

> So just because you can doesn't mean that you should. :)

> If it was me, I'd sell the 703 and buy the KX3.

> 73, Jim K9YC

Jim - there's a method to my madness.

I was planning on getting the KXPA100 as a first step, having read those reviews about the '703 (which has been a fun radio for me running QRP).

Then, after driving the KXPA100 and seeing if it's not delivering a clean signal, I can say to the long-suffering Mrs. KC2LST "Wow, I really miscalculated. Looks like I'm going to NEED to go out and get a KX3 since I can't put this kind of signal on the air."

Now, I can add "And, K9YC said I'd better get a KX3."

Of course, she will quite rightly say "Didn't you just put a sub-receiver something-or-other into your K3 a few months ago?"

:-)

Hope to see you all on the air this weekend on Field Day!

73 de Tyler, KC2LST