[Elecraft] K3 Strange Problem

[Don Wilhelm]

Joe,

You results seem to be erratic.

Loose PL-259s can cause symptoms like that.  Finger tight for PL-259s is 
not good enough, the connectors must be seated in the notches, and after 
finger-tightening, must be torqued a bit more with pliers to obtain a 
secure connection.  The connection to the coax shell depends on having 
them tight.  Also check to be certain all PL-259s have good soldering to 
the braid.  That is the cause of many problems that work well one time, 
but fail the next time it is tried.  A bad connection to the shield can 
(and will) produce a HIGH SWR indication.

I am not saying you have exactly the problems I have indicated, but 
something similar may be present.

73,
Don W3FPR

On 11/1/2011 9:24 PM, Joe Ford wrote:
> Guy, Don
>
> I don't get the emails just the digest show your emails to me.
>
> I agree the antenna should be the first place and in fact I did look 
> at it hanging in the air but I have not lowered it to give it a closer 
> inspection. Unfortunately my antenna analyzer is one MFJ's first and 
> only gives SWR and Resistance. It did not really show anything 
> helpful. Since it is an 88' long dipole it isn't resonant any any of 
> the bands.
>
> Here is what is strange about this. I have only had the K3 a few 
> weeks. I did not have a problem tuning on 30m. The first time the 
> problem occurred was when I went SPLIT then turned on the SUB rx. 
> Immediately it gave the HIGH SWR warning. Then I tried tune and got 
> the strange tuning behavior. So I began to trouble shoot the problem. 
> I tried different combinations of settings, etc. The antenna comes in 
> to an antenna switch with one position on the K3 and the other on the 
> K2. I wanted to eliminate the switch and connect directly to the coax 
> coming from the balun. To get to where I could make that connection I 
> had to completely disconnect everything from the back of the K3 and 
> move close enough to reach that coax, thus bypassing the switch. So I 
> did that and when I tried a tune I got the same result, it tuned to 
> the same spot and stopped. No difference. Then I redid all the cables 
> to the rear of the K3. And guess what. This time when I hit tune it 
> went right to 1:1.2 without hardly any relay action. So did some 
> tests, retuning and so forth. It continued to work okay. I even had a 
> qso with a good rst.
>
> That was last Saturday. On Sunday afternoon, I came in and tuning on 
> 30m found a dx station working pileup. That is when I went A>B, SPLIT 
> and then turned on SUB. As soon as I hit the paddle and it went to 
> transmit, the HIGH SWR message appeared and when I tried ANT TUNE it 
> tuned just like it had before. SWR shows max and RF out shows min 
> while relays are working, then it SWR drops to 1:1.8 to 2 and power 
> out shows 100w (what it is set for).  I don't know why the problem 
> went away when it did, I have not been able to duplicate again. d
>
> I'll take down the ant and inspect it.But it works fine on all the 
> other bands. Tunes with no problems all other bands. The KAT100 tunes 
> but the KAT3 doesn't?
>
> Thanks, guys, for your suggestions.
>
> Joe
> k4nvj