[Elecraft] K1 issue on 20M (not crystal related)

[Don Herring]

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
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