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K1 issue on 20M (not crystal related)

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Don Herring

K1 issue on 20M (not crystal related)

Greetings

I'm a newbie building a K1-4. Everything was going OK until the
receiver alignment phase of the build where I ran into a problem where I
could not hear anything on 20M.

After searching the list and several exchanges with Elecraft support, I
had not gotten anywhere in resolving the problem. Based on previous
issues seen on the list regarding 20M, Elecraft did send me a couple of
replacement crystals for the band.

In the mean time, I completed the transmitter section and was able to
get output on 40, 30, and 15 - no output on 20 as per an external
wattmeter.

Replacing the 20M crystal had no effect. Using my Ten-Tec RX-320D, I
was able to verify operation of all the crystals, including 20M.

I put together a RF probe this weekend and started signal tracing. This
is what I have found, though the finding does not make much sense to my
inexperienced mind.

At step 8 in the signal tracing procedure in the K1 Manual, I was
getting 0 voltage on 20M, and anywhere from 0.025 t0 .035 on the other
bands.

I started tracing back from P1 pin 6, and took a reading at T2 which is
the source of my puzzlement.

I can see voltage on all bands going into T2 on lead 3, but no voltage
at lead 2 for 20M - I'm getting a reading on lead 2 for all other bands.

So it appears T2 may be the source of my problem. But it doesn't click
with me that the toroid can be a problem with just one band.

One other oddity is that even though I'm not seeing any signal on the
external wattmeter I can hear 20M on the RX-320.

Am I on the right track here, or do I need further testing before
working on T2?

THX, and 73

Don, KJ4MRB
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Don Wilhelm-4

Re: K1 issue on 20M (not crystal related)

Don,

Are you certain you have the Pre-mixer capacitors set properly for 15
meters? It is quite possible to set them for a response in the 31 MHz
range instead of the correct 25 MHz range. If that happens, you will
not be able to align the Pre-mix bandpass to 20 meters. Start with the
15 meter capacitors set near the center position (with the slot pointing
to the narrow end of the capacitor) and do not vary them more than 30
degrees from that position while tuning.

Be certain you are really hearing signals in the 15 meter band when
doing the initial receive alignment of the pre-mixer bandpass filter.
If you do not have a signal generator for 15 meters, use another ham
transmitter transmitting at low power into a dummy load and connect a
short antenna wire to the K1 - place the wire near the dummy load.

After aligning 15 meters, try aligning 20 meters again.

73,
Don W3FPR

Don Herring wrote:

> Greetings
>
> I'm a newbie building a K1-4. Everything was going OK until the
> receiver alignment phase of the build where I ran into a problem where I
> could not hear anything on 20M.
>
> After searching the list and several exchanges with Elecraft support, I
> had not gotten anywhere in resolving the problem. Based on previous
> issues seen on the list regarding 20M, Elecraft did send me a couple of
> replacement crystals for the band.
>
> In the mean time, I completed the transmitter section and was able to
> get output on 40, 30, and 15 - no output on 20 as per an external
> wattmeter.
>
> Replacing the 20M crystal had no effect. Using my Ten-Tec RX-320D, I
> was able to verify operation of all the crystals, including 20M.
>
> I put together a RF probe this weekend and started signal tracing. This
> is what I have found, though the finding does not make much sense to my
> inexperienced mind.
>
> At step 8 in the signal tracing procedure in the K1 Manual, I was
> getting 0 voltage on 20M, and anywhere from 0.025 t0 .035 on the other
> bands.
>
> I started tracing back from P1 pin 6, and took a reading at T2 which is
> the source of my puzzlement.
>
> I can see voltage on all bands going into T2 on lead 3, but no voltage
> at lead 2 for 20M - I'm getting a reading on lead 2 for all other bands.
>
> So it appears T2 may be the source of my problem. But it doesn't click
> with me that the toroid can be a problem with just one band.
>
> One other oddity is that even though I'm not seeing any signal on the
> external wattmeter I can hear 20M on the RX-320.
>
> Am I on the right track here, or do I need further testing before
> working on T2?
>
> THX, and 73
>
> Don, KJ4MRB
> ______________________________________________________________
> 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
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.375 / Virus Database: 270.13.10/2231 - Release Date: 07/11/09 05:57:00
>
>

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Don Herring

Re: K1 issue on 20M (not crystal related)

Thank you, that appears to have been the problem.

While I don't have access to a signal generator or another transmitter,
I did find a strong signal on 15. I then worked on 20 and low and
behold, the band came alive.

I now feel that I can proceed with the KAT1 and finish this thing up.

But before I install the KAT1, I will try to locate a signal generator
and make sure I've got everything aligned before installing the tuner.

Thanks again

73,
Don KJ4MRB

Don Wilhelm wrote:

> Don,
>
> Are you certain you have the Pre-mixer capacitors set properly for 15
> meters? It is quite possible to set them for a response in the 31 MHz
> range instead of the correct 25 MHz range. If that happens, you will
> not be able to align the Pre-mix bandpass to 20 meters. Start with
> the 15 meter capacitors set near the center position (with the slot
> pointing to the narrow end of the capacitor) and do not vary them more
> than 30 degrees from that position while tuning.
>
> Be certain you are really hearing signals in the 15 meter band when
> doing the initial receive alignment of the pre-mixer bandpass filter.
> If you do not have a signal generator for 15 meters, use another ham
> transmitter transmitting at low power into a dummy load and connect a
> short antenna wire to the K1 - place the wire near the dummy load.
>
> After aligning 15 meters, try aligning 20 meters again.
>
> 73,
> Don W3FPR
>
> Don Herring wrote:
>> Greetings
>>
>> I'm a newbie building a K1-4. Everything was going OK until the
>> receiver alignment phase of the build where I ran into a problem
>> where I could not hear anything on 20M.
>>
>> After searching the list and several exchanges with Elecraft support,
>> I had not gotten anywhere in resolving the problem. Based on
>> previous issues seen on the list regarding 20M, Elecraft did send me
>> a couple of replacement crystals for the band.
>>
>> In the mean time, I completed the transmitter section and was able to
>> get output on 40, 30, and 15 - no output on 20 as per an external
>> wattmeter.
>>
>> Replacing the 20M crystal had no effect. Using my Ten-Tec RX-320D, I
>> was able to verify operation of all the crystals, including 20M.
>>
>> I put together a RF probe this weekend and started signal tracing.
>> This is what I have found, though the finding does not make much
>> sense to my inexperienced mind.
>>
>> At step 8 in the signal tracing procedure in the K1 Manual, I was
>> getting 0 voltage on 20M, and anywhere from 0.025 t0 .035 on the
>> other bands.
>> I started tracing back from P1 pin 6, and took a reading at T2 which
>> is the source of my puzzlement.
>>
>> I can see voltage on all bands going into T2 on lead 3, but no
>> voltage at lead 2 for 20M - I'm getting a reading on lead 2 for all
>> other bands.
>>
>> So it appears T2 may be the source of my problem. But it doesn't
>> click with me that the toroid can be a problem with just one band.
>>
>> One other oddity is that even though I'm not seeing any signal on the
>> external wattmeter I can hear 20M on the RX-320.
>>
>> Am I on the right track here, or do I need further testing before
>> working on T2?
>>
>> THX, and 73
>>
>> Don, KJ4MRB
>> ______________________________________________________________
>> 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
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - www.avg.com Version: 8.5.375 / Virus Database:
>> 270.13.10/2231 - Release Date: 07/11/09 05:57:00
>>
>>
>