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K3 synthesizer problem

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NQ7R

K3 synthesizer problem

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k6dgw

Re: K3 synthesizer problem

On 2/9/2012 4:07 PM, Tom Kramer wrote:

> I have exchanged a number of emails with Gary Surrency about
> this with basically no conclusion and an apparent lack of desire to
> solve it.

That would be a first for this group.
>
> I discovered that when attempting to transmit between 24,910.0 and
> 24,930.0 the swr bar graph shows a pulsating full scale reading and
> the dial reads SWR between 9:1 and 12:1, and power output of maybe 20
> watts.

Do you have the K3 ATU?

If you're getting 20W with that SWR, you must have the 100W PA, true?

With an antenna connected, what do you hear on RX as you tune into one
of these regions?

Why do you think it's a synthesizer problem?

Do you have any method [another receiver] to check the freq of your TX
signal as you cross into one of the high SWR regions?

If it happened across an entire band, I'd suspect you maybe
inadvertently selected ANT2 on that band and "elephant-brain" K3
remembered it. I'd suspect that because that's what I did, and got a
phone call from Wayne -- first thing he asked me to check.

If you have the ATU and it is in AUTO, it may have "remembered" a
setting for that band segment that is wildly wrong.

Others will no doubt speak up here.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

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David Gilbert

Re: K3 synthesizer problem

In reply to this post by NQ7R

You've never said whether or not you can receive OK in those band
segments. If so, I doubt that the synth board would be the problem.

Dave AB7E

On 2/9/2012 5:07 PM, Tom Kramer wrote:

> I am a new person in this group and I will admit that I have not looked at many of the hundreds of previous posts so I will apologize in advance for being a bit lazy if this topic has been dealt with before.
>
> I have a home assembled K3 SN 4210 that has developed a most annoying problem. I have exchanged a number of emails with Gary Surrency about this with basically no conclusion and an apparent lack of desire to solve it.
>
> I discovered that when attempting to transmit between 24,910.0 and 24,930.0 the swr bar graph shows a pulsating full scale reading and the dial reads SWR between 9:1 and 12:1, and power output of maybe 20 watts. Outside this range SWR is normal and power output is full 100 watts. This can be into a resonant antenna or dummy load.
> I have done the synthesizer calibration preceded of course by the ADC ref calibration multiple times. I sent Gary a list of all the parameters outputted by these tests and he says all look to be in the normal range. I have since discovered that the same problem appears between 28,500 and 29,000 Khz as well. I am trying to keep this somewhat short so I didn't supply every detail of the testing.
> Have other people experienced this and what if any solution did you find? Gary suggests a new synthesizer board @ $200+ but no at this point there is no guarantee that will fix the problem. I have made arrangements to test this with another K3 next week, but curious if this problem is something new.
> Tom NQ7R
> Casa Grande, AZ
>

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alsopb

Re: K3 synthesizer problem

Has he done a cold reset?

It really sounds like there is no antenna attached in that band segment.

Has he tried simply removing the antenna/dummy load connection and see
if the results are the same?
If so, then clearly the antenna choice needs to be examined.

I'd be willing to bet his K3 has an antenna tuner.

73 de Brian/K3KO

On 2/9/2012 9:14 PM, David Gilbert wrote:

> You've never said whether or not you can receive OK in those band
> segments. If so, I doubt that the synth board would be the problem.
>
> Dave AB7E
>
>
>
> On 2/9/2012 5:07 PM, Tom Kramer wrote:
>
>> I am a new person in this group and I will admit that I have not looked at many of the hundreds of previous posts so I will apologize in advance for being a bit lazy if this topic has been dealt with before.
>>
>> I have a home assembled K3 SN 4210 that has developed a most annoying problem. I have exchanged a number of emails with Gary Surrency about this with basically no conclusion and an apparent lack of desire to solve it.
>>
>> I discovered that when attempting to transmit between 24,910.0 and 24,930.0 the swr bar graph shows a pulsating full scale reading and the dial reads SWR between 9:1 and 12:1, and power output of maybe 20 watts. Outside this range SWR is normal and power output is full 100 watts. This can be into a resonant antenna or dummy load.
>> I have done the synthesizer calibration preceded of course by the ADC ref calibration multiple times. I sent Gary a list of all the parameters outputted by these tests and he says all look to be in the normal range. I have since discovered that the same problem appears between 28,500 and 29,000 Khz as well. I am trying to keep this somewhat short so I didn't supply every detail of the testing.
>> Have other people experienced this and what if any solution did you find? Gary suggests a new synthesizer board @ $200+ but no at this point there is no guarantee that will fix the problem. I have made arrangements to test this with another K3 next week, but curious if this problem is something new.
>> Tom NQ7R
>> Casa Grande, AZ
>>
>>
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KeithWE6R

Re: K3 synthesizer problem NQ7R

Administrator

In reply to this post by NQ7R

Try re-tuning the KAT3 auto tuner, or bypassing it.
Try tightening the 3 LPA screws on the bottom (the ones with lock washers).
Keith

On 2/9/2012 4:07 PM, Tom Kramer wrote:

w7aqk

Re: K3 synthesizer problem

In reply to this post by NQ7R

NQ7R and all,

Tom, that does sound like a very odd problem. I Don't remember seeing it
discussed previously here. However, your suggestion that Gary Surrency may
be lacking in interest to solve it doesn't sound like Gary at all! He has
been around the Elecraft scene, almost from inception, and has always been
very responsive, and he is very good at identifying problem resolutions! My
guess is that he may simply have run out of ideas without being able to get
"hands on". Not every problem can be solved by email. It also appears that
the two of you have exchanged several emails, and that doesn't sound like
someone who is not trying to be helpful.

I suppose if you have another K3 around, and could substitute one
synthesizer board for another that way, you could probably determine whether
or not Gary's suggestion is correct. He's probably suggesting that to avoid
your having to send the rig to Elecraft for service, but that really may be
your best option due to the uncertainty. Maybe you could just send them
your synthesizer board and they could test it somehow. That might be even
easier, from a shipping standpoint. However, maybe that's not a practical
approach for whatever reason.

Anyway, I know rig problems are depressing, and I sympathize with your
frustration. There's a tendency to feel abused, since everyone else's rig
seems to be working fine, but yours isn't! Unfortunately, bad things can
happen to good people! However, I sincerely believe you are in better hands
with Elecraft than you would be with just about any other manufacturer.
When rig problems develop, and you can't fix them yourself, you have to
"bite the bullet" somewhat. You just have to work with them to determine
the most expeditious way of resolving the problem. By the way, if I had to
guess, I'd bet Gary is probably close to right in his suggestion, but since
he can't be positive, he obviously can't give you any guarantees. Unless
some other option comes to mind, I'd probably just send the rig in and be
done with it. Besides, there is usually the additional benefit of them
possibly identifying other anomalies, which they could then deal with
without necessitating another trip back and forth. Kind of like getting a
20,000 mile service on your car!

Dave W7AQK

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