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PA set up issues

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gd0tep

PA set up issues

Hi to the group,

I've just installed my KPA3 100w upgrade into my factory built K3.

I've followed the calibration procedure starting out with 5w per band, and
then moved to 50w per band, as per instructions.

I must be missing something, or perhaps not understand what I'm reading as
once I've completed the calibration, some of the HF bands are fine with 100w
out, other bands seem to upset the radio as follows: When using the radio
into a 200w 50 ohm load, and measuring power with a bird 43, I can see how
the power increases as I raise the power output, yet on certain bands there
seems to be a point where at around 85w to 90w the power out appears to fold
back and the radio switches itself off.

There doesn't seem to be any link to what band is causing the problem, as I
have the problem on 160m, 30m 21m 12m, 10m and 6m.

So, what am I missing, or perhaps I should ask 'what have I done wrong or
forgotten to do'??

73,

Andy

http://gd0tep.com

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Don Wilhelm-4

Re: PA set up issues

Andy,

I would first do the wattmeter calibration as indicated in the manual.
You can make it match your Bird if that is what you trust.
After that use K3 Utility to do the 5 and 50 watt (and 1 mW if you have
the KXV3). Using the K3 Utility to do the TX Gain calibration is a
snap, you just sit back and watch it change bands and 'do its thing'.

Re-check your conditions after those steps.

73,
Don W3FPR

GD0TEP wrote:

> Hi to the group,
>
>
>
> I've just installed my KPA3 100w upgrade into my factory built K3.
>
>
>
> I've followed the calibration procedure starting out with 5w per band, and
> then moved to 50w per band, as per instructions.
>
>
>
> I must be missing something, or perhaps not understand what I'm reading as
> once I've completed the calibration, some of the HF bands are fine with 100w
> out, other bands seem to upset the radio as follows: When using the radio
> into a 200w 50 ohm load, and measuring power with a bird 43, I can see how
> the power increases as I raise the power output, yet on certain bands there
> seems to be a point where at around 85w to 90w the power out appears to fold
> back and the radio switches itself off.
>
>
>
> There doesn't seem to be any link to what band is causing the problem, as I
> have the problem on 160m, 30m 21m 12m, 10m and 6m.
>
>
>
> So, what am I missing, or perhaps I should ask 'what have I done wrong or
> forgotten to do'??
>
>
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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gd0tep

Re: PA set up issues

Hi Don,

Thanks for the info, I downloaded the program and carried out the
calibration procedure, and yes, it was interesting to watch but didn't cure
the problem.

Here's the results I get, the power indicated is taken from the KW. I start
out at 50w, then increase the power heading towards 100w:

160m - 97w & radio trips, next test found fine adjustment of front control
made the 100w
80m - 100w Appears OK
40m - 100w Appears OK
30m - 100w Appears OK
20m - radio tripped off, next test found that all I could get is 85w before
it would trip again.
17m - 94w & radio trips off, repeated attempts results in the radio tripping
off @ 85w
15m - 95w & radio trips off, repeated attempts results in the radio tripping
off @ 94w
12m - 90w & radio trips off, repeated attempts results in the radio tripping
off @ 88w
10m - 100w
6m - 94w & radio trips off, repeated attempts results in the radio tripping
off @ 86w

So, now what should I try??

73,
Andy
http://gd0tep.com

-----Original Message-----
From: Don Wilhelm [mailto:[hidden email]]
Sent: 25 June 2010 22:50
To: GD0TEP
Cc: [hidden email]
Subject: Re: [Elecraft] PA set up issues

Andy,

I would first do the wattmeter calibration as indicated in the manual.
You can make it match your Bird if that is what you trust.
After that use K3 Utility to do the 5 and 50 watt (and 1 mW if you have the
KXV3). Using the K3 Utility to do the TX Gain calibration is a snap, you
just sit back and watch it change bands and 'do its thing'.

Re-check your conditions after those steps.

73,
Don W3FPR

GD0TEP wrote:

> Hi to the group,
>
>
>
> I've just installed my KPA3 100w upgrade into my factory built K3.
>
>
>
> I've followed the calibration procedure starting out with 5w per band,
> and then moved to 50w per band, as per instructions.
>
>
>
> I must be missing something, or perhaps not understand what I'm
> reading as once I've completed the calibration, some of the HF bands
> are fine with 100w out, other bands seem to upset the radio as
> follows: When using the radio into a 200w 50 ohm load, and measuring
> power with a bird 43, I can see how the power increases as I raise the
> power output, yet on certain bands there seems to be a point where at
> around 85w to 90w the power out appears to fold back and the radio

switches itself off.

>
>
>
> There doesn't seem to be any link to what band is causing the problem,
> as I have the problem on 160m, 30m 21m 12m, 10m and 6m.
>
>
>
> So, what am I missing, or perhaps I should ask 'what have I done wrong
> or forgotten to do'??
>
>
>

Roger D Johnson

Re: PA set up issues

GD0TEP wrote:

> Hi Don,
>
> Thanks for the info, I downloaded the program and carried out the
> calibration procedure, and yes, it was interesting to watch but didn't cure
> the problem.
>
> Here's the results I get, the power indicated is taken from the KW. I start
> out at 50w, then increase the power heading towards 100w:
>
> 160m - 97w & radio trips, next test found fine adjustment of front control
> made the 100w
> 80m - 100w Appears OK
> 40m - 100w Appears OK
> 30m - 100w Appears OK
> 20m - radio tripped off, next test found that all I could get is 85w before
> it would trip again.
> 17m - 94w & radio trips off, repeated attempts results in the radio tripping
> off @ 85w
> 15m - 95w & radio trips off, repeated attempts results in the radio tripping
> off @ 94w
> 12m - 90w & radio trips off, repeated attempts results in the radio tripping
> off @ 88w
> 10m - 100w
> 6m - 94w & radio trips off, repeated attempts results in the radio tripping
> off @ 86w
>
> So, now what should I try??
>
> 73,
> Andy
> http://gd0tep.com
>
>
>

Hi Andy....

I had the same problem originally. It was the power supply current
limiting! Supposedly,
a 25 amp supply, it would start limiting at about 18-20 amps. This
dropped the voltage
which would cause the radio to shut itself off.

73, Roger

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Don Wilhelm-4

Re: PA set up issues

Andy,

As Roger suggested, check your power supply - I did not initially
realize that the K3 "trips off", I had previously thought that it had
reached some maximum power that it would not go above. Check the power
cable connections to be certain they are tight both inside and outside
the power supply enclosure.
If that is not the problem --
Measure the current drawn just below just below the point where the K3
trips off and include that information in an email to [hidden email]

73,
Don W3FPR

Roger D Johnson wrote:

> GD0TEP wrote:
>
>> Hi Don,
>>
>> Thanks for the info, I downloaded the program and carried out the
>> calibration procedure, and yes, it was interesting to watch but didn't cure
>> the problem.
>>
>> Here's the results I get, the power indicated is taken from the KW. I start
>> out at 50w, then increase the power heading towards 100w:
>>
>> 160m - 97w & radio trips, next test found fine adjustment of front control
>> made the 100w
>> 80m - 100w Appears OK
>> 40m - 100w Appears OK
>> 30m - 100w Appears OK
>> 20m - radio tripped off, next test found that all I could get is 85w before
>> it would trip again.
>> 17m - 94w & radio trips off, repeated attempts results in the radio tripping
>> off @ 85w
>> 15m - 95w & radio trips off, repeated attempts results in the radio tripping
>> off @ 94w
>> 12m - 90w & radio trips off, repeated attempts results in the radio tripping
>> off @ 88w
>> 10m - 100w
>> 6m - 94w & radio trips off, repeated attempts results in the radio tripping
>> off @ 86w
>>
>> So, now what should I try??
>>
>> 73,
>> Andy
>> http://gd0tep.com
>>
>>
>>
>>
> Hi Andy....
>
> I had the same problem originally. It was the power supply current
> limiting! Supposedly,
> a 25 amp supply, it would start limiting at about 18-20 amps. This
> dropped the voltage
> which would cause the radio to shut itself off.
>
> 73, Roger
>
> ______________________________________________________________
> 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
>
>

gd0tep

Re: PA set up issues

Aha...

Although I don't see any problems with the PSU I was trying, I moved the K3
over to my shack main PSU, a 72a jobby that is fine when more than one radio
is TXing at the same time.

You were of course all correct, the radio is fine so it must have been the
original PSU. DOH!

All sorted, my thanks to everyone for the response to my original query.

73,
Andy
http://gd0tep.com

-----Original Message-----
From: Don Wilhelm [mailto:[hidden email]]
Sent: 26 June 2010 17:57
To: GD0TEP
Cc: [hidden email]
Subject: Re: [Elecraft] PA set up issues

Andy,

As Roger suggested, check your power supply - I did not initially realize
that the K3 "trips off", I had previously thought that it had reached some
maximum power that it would not go above. Check the power cable connections
to be certain they are tight both inside and outside the power supply
enclosure.
If that is not the problem --
Measure the current drawn just below just below the point where the K3 trips
off and include that information in an email to [hidden email]

73,
Don W3FPR

Roger D Johnson wrote:

> GD0TEP wrote:
>
>> Hi Don,
>>
>> Thanks for the info, I downloaded the program and carried out the
>> calibration procedure, and yes, it was interesting to watch but
>> didn't cure the problem.
>>
>> Here's the results I get, the power indicated is taken from the KW. I
>> start out at 50w, then increase the power heading towards 100w:
>>
>> 160m - 97w & radio trips, next test found fine adjustment of front
>> control made the 100w 80m - 100w Appears OK 40m - 100w Appears OK 30m
>> - 100w Appears OK 20m - radio tripped off, next test found that all I
>> could get is 85w before it would trip again.
>> 17m - 94w & radio trips off, repeated attempts results in the radio
>> tripping off @ 85w 15m - 95w & radio trips off, repeated attempts
>> results in the radio tripping off @ 94w 12m - 90w & radio trips off,
>> repeated attempts results in the radio tripping off @ 88w 10m - 100w
>> 6m - 94w & radio trips off, repeated attempts results in the radio
>> tripping off @ 86w
>>
>> So, now what should I try??
>>
>> 73,
>> Andy
>> http://gd0tep.com
>>
>>
>>
>>
> Hi Andy....
>
> I had the same problem originally. It was the power supply current
> limiting! Supposedly, a 25 amp supply, it would start limiting at
> about 18-20 amps. This dropped the voltage which would cause the radio
> to shut itself off.
>
> 73, Roger
>
> ______________________________________________________________
> 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
>
>