A happy K2 post - for a change......

[DaveL G3TJP]

I'd been unhappy with the stiffness of my K2's rotary encoder for a while, so when a replacement unit was provided by Scott, I thought it was time for a makeover of my fully loaded K2/100.

The new rotary encoder was definitely an improvement. The original encoder was stiff to turn, even in the absence of the felt washer friction pad, but the new encoder was so free-running, I had to dig out and install that piece of felt. Thanks a million, Scott, the feel of the rig has been improved immensely.

I also took the opportunity to replace the AF gain pot, which had a wobbly knobbly. It had no effect on performance, but every time I moved the AF gain control, I was distracted by the knob's wobble.

While the lid was off, I decided to do a complete realignment. Again, I found a good setting of L34 difficult to achieve. For me, Spectrogram, with its ever-changing display, proved unhelpful but very careful listening to a weak signal from my genny on 14MHz found a gentle but significant dip in the background noise. AGC voltage setup range ran up to 3.83v and at ALL settings, the AGC reduced the level of a very weak (S1 or less) signal. Eventually I settled on 3.68v as the one that had least effect on a signal just above the noise floor, but there should have been a point where the AGC action cut off..

It was interesting to note that after several months of use, slight improvements could be made to most settings, either because a "bedding in" had taken place or my values had changed.

I was very impressed with the residual carrier suppression on SSB. I used a GC Rx with antenna to monitor the carrier level on SSB when transmitted into another antenna. The antennas were only a few feet apart, but a small adjustment left only a very weak residual carrier on SSB. It was lower than the 1uV level from the Elecraft XG2!

I found that the screws on one of the KPA100 PA transistors could be tightened by maybe a little less than 1/8 of a turn. The other was yomped down good and tight. A slight improvement of SWR eedback was achieved and the PA bias setting proved far more docile to adjust than my recollection of it when newly constructed. There was far less "drift" as the transistors warmed up.

I then went off the rails. It was my intention to check higher power output against a "reasonable" wattmeter. When I held "Tune", regardless of the higher power setting, I only saw 22W until I moved the power output control. Somewhat bewildered, I took a break to allow my limited mental resource to do a spot of background processing. Sure enough, the back of my mind came up trumps. Tune limits the output to approx, 2W in QRP and 20W in QRO. Press Tune and Display to override. Yep! Another case of RTFM!  Doh!

I did find one parameter of 8-somethingorother was set to "nor" and not to "hold" as the KPA100 manual instructs, but switching between its original setting and the instructed setting didn't seem to make any difference. Eventually, I went with the manual's recommended setting.

Overall, I reckon to have squeezed a little more out of the K2.  I haven't been able to get an audio report on the slightly changed SSB filter settings but prior to adjustment, I had good reports on SSB audio, despite my rather deep voice. I've moved the notional baseline of all the filters available in SSB up by 50Hz approx. Time and a co-operative local who knows my voice will tell.

Was it worth it. Most definitely YES. Some settings had either drifted slightly or my interpretation had changed. I managed to reduce tuning display inaccuracy from approx 30Hz to less than 10Hz and make improvements to a few more settings. Were they significant? NO, I doubt it, but it DID provide a refresher course and it leaves me satisfied for the time being. It's good to touch base occasionally.

As with all home constructed equipment, there's always a nagging feeling that "something" can be improved upon. Is this the eternal treadmill to which we are all consigned? It's an undoubted YES for me.

As recommended on my bulletin board, think twice, post once.

73 all, DaveL G3TJP
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[Stephen W. Kercel]

My K2 developed this same exact problem. Extracting the felt bits put
everything right.

73,

Steve Kercel
AA4AK


At 11:36 PM 1/24/2008, Ron D'Eau Claire wrote:

>David, G3TJP wrote:
>
>I'd been unhappy with the stiffness of my K2's rotary encoder for a while,
>so when a replacement unit was provided by Scott, I thought it was time for
>a makeover of my fully loaded K2/100.
>
>-----------------------------
>
>Check that stiff encoder very carefully. It may be fine AFTER you carefully
>unwind some bits of the felt from the bearing and it'll be a FB spare.
>
>My old K2 developed that problem several months after I built it. Looking
>closely I could see some bits of the felt hairs caught in the C-ring and
>bearing. I carefully tugged gently on each hair with tweezers while turning
>the shaft in the direction needed to unwind each one and, after removing
>several of them suddenly the encoder ran free again.
>
>Then I used a bit of "superglue" seal the inside edge of the hole in the
>felt washer so other threads wouldn't get entangled and replaced it. I never
>had the problem again.
>
>Ron AC7AC
>
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[DaveL G3TJP]

First of all, apologies for the loooong lines in my earlier post.  I wrote the item using a wordprocessor then cut and
pasted it into an email window.

Thanks for the suggestions from Ron, Tom and Steve re. the felt washer fibres, but it was absolutely and definitely
NOT that.

The original encoder was so stiff the felt washer wasn't put to use and the first thing I checked was where the shaft
rotated in the body.  I've built other K2's and the encoder in mine was far stiffer to rotate, straight out of the bag,
 than the others.  I fitted it and used it in the hope that it would free up after a while but it didn't.  

Neal mailed me off-list to ask what RTFM meant.  It's such a common expression here in the UK, that it
didn't occur to me that it might be unknown elsewhere.  Its approximate translation, although other words are
sometimes substituted for the one starting with "f", is "Read the flipping manual".   YMMV.

73 all.  DaveL  G3TJP
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[Augie "Gus" Hansen]

Ron D'Eau Claire wrote:
> ...
> Even though I write many of the Elecraft assembly manuals, I never write
> "RTFM". Here in the colonies it tends to be associated with a somewhat more
> vulgar term.
>
> Mind you, I might THINK it some times, but I'd never SAY it, not because I'm
> so polite but because I've been caught not reading the docs myself!
>  

"Read the Fine Manual" goes well in polite company, and fine is the word
I use to describe the manuals you and others have written for Elecraft
products. Keep up the fine work!

Gus Hansen
KB0YH
Denver, CO

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[dave.wilburn]

I second that.  I was helping a friend over the radio the other day.
He was trying to install the auto-tuner he bought for his Jupiter.  He
was confused, as they used different terms in their manuals, for the
the various wires, at various points in the manuals.  I thought I
would go grab a copy of the manual and read through it, that whole two
heads being better than one thing.  This turned out to be fruitless,
as I could not even find the manuals on the website.


Dave Wilburn
K4DGW
K2/100 - S/N 5982


Augie Hansen wrote:

> Ron D'Eau Claire wrote:
>> ...
>> Even though I write many of the Elecraft assembly manuals, I never write
>> "RTFM". Here in the colonies it tends to be associated with a somewhat
>> more
>> vulgar term.
>> Mind you, I might THINK it some times, but I'd never SAY it, not
>> because I'm
>> so polite but because I've been caught not reading the docs myself!
>>  
>
> "Read the Fine Manual" goes well in polite company, and fine is the word
> I use to describe the manuals you and others have written for Elecraft
> products. Keep up the fine work!
>
> Gus Hansen
> KB0YH
> Denver, CO
>
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> Elecraft web page: http://www.elecraft.com
>

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