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KXPA100 not making antenna connection

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Josh Lehan

KXPA100 not making antenna connection

Hi there!

I assembled my KXPA100 (with ATU) recently, serial number 0595.
Unfortunately, it isn't working. The link to the KX3 works great
(rather slick, everything was instantly recognized), but the KXPA100 is
not making any antenna connection cleanly. KX3 is properly configured
to link with the KXPA100.

I heard nothing at all, on any band, as if the antenna wasn't connected
at all. I tried initiating an ATU tuning cycle, only to see a SWR fault
on the KXPA100 almost instantly, so I stopped that rather quickly. The
SWR wouldn't improve below 32.0-1 (terrible).

I opened it up again and removed then reconnected the tricky little TMP
connectors, and that helped a little. Using needlenose pliers made all
the difference. I am now pretty confident I have the TMP connectors
fully inserted (they weren't, earlier). Now, I can hear stations very
faintly, S0 at most (not enough to light up any signal bars on the KX3).
This is still very bad, because when bypassing the KXPA100 by using a
barrel connector to connect the KX3 to the antenna directly (for
testing), it's loud and clear, around S5-S9, which is normal for my antenna.

I can transmit just fine, using the KX3 and its built-in ATU, without
the KXPA100, so I can rule out anything else in my setup that might be
causing a problem. Both antenna and dummy load normally work great.
Ruled out cables by using barrel connector to join two cables together
directly (cutting the KXPA100 out of the circuit) and that also worked
great. I just can't get a good connection when going through the KXPA100.

Now, I'm at a loss what to do. I think there might be a fault with the
ATU connection internally of the KXPA100. It was straightforward to put
it together, though, I don't think I made any mistakes there, but
probably will disassemble it all and try again.

Switching between antenna 1 and antenna 2 makes an audible difference in
the noise level, so I know that works. However, the ATU switch on the
KXPA100 doesn't seem to make a difference at all, there is no difference
in noise level between bypass/manual/auto. Shouldn't there be an
audible difference here? There also is no difference when KXPA100 is
powered off vs. on, which seems strange to me. Same SWR fault happens
instantly when trying to tune with ATU, or doing any transmission for
that matter.

What should be my next step in troubleshooting?

Thanks!

Josh
K6JSH
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Kurt Pawlikowski

Re: KXPA100 not making antenna connection

Josh,

Unfortunately, I'm not familiar enough with the KXPA100 to know if,
when bypassing the unit internally, there is DC continuity between the
input and output. If there is (I suspect so), you should be able to
measure between them with a regular ohm meter. While not 100%
definitive, if it fails this test (again, assuming DC continuity), that
would be a major indicator of some connection problem.

Hope that helps!

kurtt WB9FMC
2015 Hamfesters Hamfest Chairman
Looking for my replacement since 2014!
http:\\ham-ham.org

On 9/3/2014 03:24, Josh Lehan wrote:

> Hi there!
>
> I assembled my KXPA100 (with ATU) recently, serial number 0595.
> Unfortunately, it isn't working. The link to the KX3 works great
> (rather slick, everything was instantly recognized), but the KXPA100 is
> not making any antenna connection cleanly. KX3 is properly configured
> to link with the KXPA100.
>
> I heard nothing at all, on any band, as if the antenna wasn't connected
> at all. I tried initiating an ATU tuning cycle, only to see a SWR fault
> on the KXPA100 almost instantly, so I stopped that rather quickly. The
> SWR wouldn't improve below 32.0-1 (terrible).
>
> I opened it up again and removed then reconnected the tricky little TMP
> connectors, and that helped a little. Using needlenose pliers made all
> the difference. I am now pretty confident I have the TMP connectors
> fully inserted (they weren't, earlier). Now, I can hear stations very
> faintly, S0 at most (not enough to light up any signal bars on the KX3).
> This is still very bad, because when bypassing the KXPA100 by using a
> barrel connector to connect the KX3 to the antenna directly (for
> testing), it's loud and clear, around S5-S9, which is normal for my antenna.
>
> I can transmit just fine, using the KX3 and its built-in ATU, without
> the KXPA100, so I can rule out anything else in my setup that might be
> causing a problem. Both antenna and dummy load normally work great.
> Ruled out cables by using barrel connector to join two cables together
> directly (cutting the KXPA100 out of the circuit) and that also worked
> great. I just can't get a good connection when going through the KXPA100.
>
> Now, I'm at a loss what to do. I think there might be a fault with the
> ATU connection internally of the KXPA100. It was straightforward to put
> it together, though, I don't think I made any mistakes there, but
> probably will disassemble it all and try again.
>
> Switching between antenna 1 and antenna 2 makes an audible difference in
> the noise level, so I know that works. However, the ATU switch on the
> KXPA100 doesn't seem to make a difference at all, there is no difference
> in noise level between bypass/manual/auto. Shouldn't there be an
> audible difference here? There also is no difference when KXPA100 is
> powered off vs. on, which seems strange to me. Same SWR fault happens
> instantly when trying to tune with ATU, or doing any transmission for
> that matter.
>
> What should be my next step in troubleshooting?
>
> Thanks!
>
> Josh
> K6JSH
> ______________________________________________________________
> 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]
>

______________________________________________________________
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]

Josh Lehan

Re: KXPA100 not making antenna connection

On 09/03/2014 03:17 AM, Kurt Pawlikowski wrote:
> Josh,
>
> Unfortunately, I'm not familiar enough with the KXPA100 to know if,
> when bypassing the unit internally, there is DC continuity between the
> input and output. If there is (I suspect so), you should be able to
> measure between them with a regular ohm meter. While not 100%
> definitive, if it fails this test (again, assuming DC continuity), that
> would be a major indicator of some connection problem.

Good advice. I used a multimeter to measure for continuity. Yikes, the
tip and the ring of my "RX IN" jack appear to be shorted to each other,
and also shorted to ground! Is that normal?

I'm going to open it up and check the wires carefully on the panel where
the jacks are, hopefully nothing is touching.

I've heard that measuring antenna stuff at DC can be an illusion, as
some things are supposed to appear open or appear shorted at DC, as
they're designed to carry RF, not DC. My meter can only measure
resistance at DC, it can't do anything fancier (no capacitance or
inductance, no measuring resistance at AC/RF, no impedance or reactance).

Also, when the antenna is selected, the tip and the ring of "ANT 1" (or
"ANT 2" if selected) also appear to be shorted to each other and to
ground. The KXPA100 isolates the antenna that is *not* selected: its
ring is still shorted to ground, but its tip has no connection.

Josh
K6JSH

>
> Hope that helps!
>
>
> kurtt WB9FMC
> 2015 Hamfesters Hamfest Chairman
> Looking for my replacement since 2014!
> http:\\ham-ham.org
>
> On 9/3/2014 03:24, Josh Lehan wrote:
>> Hi there!
>>
>> I assembled my KXPA100 (with ATU) recently, serial number 0595.
>> Unfortunately, it isn't working. The link to the KX3 works great
>> (rather slick, everything was instantly recognized), but the KXPA100 is
>> not making any antenna connection cleanly. KX3 is properly configured
>> to link with the KXPA100.
>>
>> I heard nothing at all, on any band, as if the antenna wasn't connected
>> at all. I tried initiating an ATU tuning cycle, only to see a SWR fault
>> on the KXPA100 almost instantly, so I stopped that rather quickly. The
>> SWR wouldn't improve below 32.0-1 (terrible).
>>
>> I opened it up again and removed then reconnected the tricky little TMP
>> connectors, and that helped a little. Using needlenose pliers made all
>> the difference. I am now pretty confident I have the TMP connectors
>> fully inserted (they weren't, earlier). Now, I can hear stations very
>> faintly, S0 at most (not enough to light up any signal bars on the KX3).
>> This is still very bad, because when bypassing the KXPA100 by using a
>> barrel connector to connect the KX3 to the antenna directly (for
>> testing), it's loud and clear, around S5-S9, which is normal for my
>> antenna.
>>
>> I can transmit just fine, using the KX3 and its built-in ATU, without
>> the KXPA100, so I can rule out anything else in my setup that might be
>> causing a problem. Both antenna and dummy load normally work great.
>> Ruled out cables by using barrel connector to join two cables together
>> directly (cutting the KXPA100 out of the circuit) and that also worked
>> great. I just can't get a good connection when going through the
>> KXPA100.
>>
>> Now, I'm at a loss what to do. I think there might be a fault with the
>> ATU connection internally of the KXPA100. It was straightforward to put
>> it together, though, I don't think I made any mistakes there, but
>> probably will disassemble it all and try again.
>>
>> Switching between antenna 1 and antenna 2 makes an audible difference in
>> the noise level, so I know that works. However, the ATU switch on the
>> KXPA100 doesn't seem to make a difference at all, there is no difference
>> in noise level between bypass/manual/auto. Shouldn't there be an
>> audible difference here? There also is no difference when KXPA100 is
>> powered off vs. on, which seems strange to me. Same SWR fault happens
>> instantly when trying to tune with ATU, or doing any transmission for
>> that matter.
>>
>> What should be my next step in troubleshooting?
>>
>> Thanks!
>>
>> Josh
>> K6JSH
>> ______________________________________________________________
>> 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]
>>
>
>

Don Wilhelm-4

Re: KXPA100 not making antenna connection

Josh,

Yes, DC measurements can be confusing - it all depends on the input and
output networks.
Rather than attempting to make that measurement at DC, connect your
antenna analyzer to the RF IN jack and a dummy load to the ANT jack.

73,
Don W3FPR

On 9/3/2014 5:41 PM, Josh Lehan wrote:

Kurt Pawlikowski

Re: KXPA100 not making antenna connection

In reply to this post by Josh Lehan

Josh,

Looking at the owner's manual, page 41, there is a simplified
schematic. In theory, if the unit is in "bypass," it should be a direct
"in" to "out" connection. There could still be some other
considerations, but I would suspect that's the way it is. Until someone
from Elecraft says otherwise or someone with a working unit can measure
theirs to disprove of prove the idea, I would operate under that
assumption. You might also want to give the good folks at Elecraft a
call about your problem. Maybe it has a very simple solution.

Hope you get it operational soon!

kurtt WB9FMC
2015 Hamfesters Hamfest Chairman
Looking for my replacement since 2014!
http:\\ham-ham.org

On 9/3/2014 16:41, Josh Lehan wrote:

> On 09/03/2014 03:17 AM, Kurt Pawlikowski wrote:
>> Josh,
>>
>> Unfortunately, I'm not familiar enough with the KXPA100 to know if,
>> when bypassing the unit internally, there is DC continuity between the
>> input and output. If there is (I suspect so), you should be able to
>> measure between them with a regular ohm meter. While not 100%
>> definitive, if it fails this test (again, assuming DC continuity), that
>> would be a major indicator of some connection problem.
> Good advice. I used a multimeter to measure for continuity. Yikes, the
> tip and the ring of my "RX IN" jack appear to be shorted to each other,
> and also shorted to ground! Is that normal?
>
> I'm going to open it up and check the wires carefully on the panel where
> the jacks are, hopefully nothing is touching.
>
> I've heard that measuring antenna stuff at DC can be an illusion, as
> some things are supposed to appear open or appear shorted at DC, as
> they're designed to carry RF, not DC. My meter can only measure
> resistance at DC, it can't do anything fancier (no capacitance or
> inductance, no measuring resistance at AC/RF, no impedance or reactance).
>
> Also, when the antenna is selected, the tip and the ring of "ANT 1" (or
> "ANT 2" if selected) also appear to be shorted to each other and to
> ground. The KXPA100 isolates the antenna that is *not* selected: its
> ring is still shorted to ground, but its tip has no connection.
>
> Josh
> K6JSH
>
>
>> Hope that helps!
>>
>>
>> kurtt WB9FMC
>> 2015 Hamfesters Hamfest Chairman
>> Looking for my replacement since 2014!
>> http:\\ham-ham.org
>>
>> On 9/3/2014 03:24, Josh Lehan wrote:
>>> Hi there!
>>>
>>> I assembled my KXPA100 (with ATU) recently, serial number 0595.
>>> Unfortunately, it isn't working. The link to the KX3 works great
>>> (rather slick, everything was instantly recognized), but the KXPA100 is
>>> not making any antenna connection cleanly. KX3 is properly configured
>>> to link with the KXPA100.
>>>
>>> I heard nothing at all, on any band, as if the antenna wasn't connected
>>> at all. I tried initiating an ATU tuning cycle, only to see a SWR fault
>>> on the KXPA100 almost instantly, so I stopped that rather quickly. The
>>> SWR wouldn't improve below 32.0-1 (terrible).
>>>
>>> I opened it up again and removed then reconnected the tricky little TMP
>>> connectors, and that helped a little. Using needlenose pliers made all
>>> the difference. I am now pretty confident I have the TMP connectors
>>> fully inserted (they weren't, earlier). Now, I can hear stations very
>>> faintly, S0 at most (not enough to light up any signal bars on the KX3).
>>> This is still very bad, because when bypassing the KXPA100 by using a
>>> barrel connector to connect the KX3 to the antenna directly (for
>>> testing), it's loud and clear, around S5-S9, which is normal for my
>>> antenna.
>>>
>>> I can transmit just fine, using the KX3 and its built-in ATU, without
>>> the KXPA100, so I can rule out anything else in my setup that might be
>>> causing a problem. Both antenna and dummy load normally work great.
>>> Ruled out cables by using barrel connector to join two cables together
>>> directly (cutting the KXPA100 out of the circuit) and that also worked
>>> great. I just can't get a good connection when going through the
>>> KXPA100.
>>>
>>> Now, I'm at a loss what to do. I think there might be a fault with the
>>> ATU connection internally of the KXPA100. It was straightforward to put
>>> it together, though, I don't think I made any mistakes there, but
>>> probably will disassemble it all and try again.
>>>
>>> Switching between antenna 1 and antenna 2 makes an audible difference in
>>> the noise level, so I know that works. However, the ATU switch on the
>>> KXPA100 doesn't seem to make a difference at all, there is no difference
>>> in noise level between bypass/manual/auto. Shouldn't there be an
>>> audible difference here? There also is no difference when KXPA100 is
>>> powered off vs. on, which seems strange to me. Same SWR fault happens
>>> instantly when trying to tune with ATU, or doing any transmission for
>>> that matter.
>>>
>>> What should be my next step in troubleshooting?
>>>
>>> Thanks!
>>>
>>> Josh
>>> K6JSH
>>> ______________________________________________________________
>>> 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]
>>>
>>
>