K2 finished

[lstavenhagen]

Hi all,

Finally finished the K2 last night, all that remains is the final assembly but I've run out of parts except the speaker and a couple jacks and screws here and there for the final assy.

I made my first, and as far as I know at this time, only, mistake when putting in the LP filter coils. when winding L21, I was looking at the turns spec for L22. I happily soldered it in and while admiring my work, noticed the wrong number of turns hi hi! So I at least caught it before I'd continued on with the build. Some solder wick and a few 4 letter words and I got it out. There was enough lead left to go ahead and install it at L22 where it was supposed to go so no harm done in the end.

Like I said, Im hoping that's my only mistake!

The last part of the alignment seemed to go correctly. A couple things I noted were first, in receive, peaking the bandpass filter coils had a practically undetectable peak. So I was worried that I'd messed something up. But on the xmitter alignment I was able to see a detectable peak on the wattmeter so that indicates to me the filter is working.
The only other thing is the current draw in transmit seems slightly high on 15M when I (of course very breifly ;)) max out the power output. The current draw seems to go up to about 3.5 amps on the internal ammeter. The rest of the bands seems like around 3 amps is the max. Otherwise, it seems nominal and the same as other bands at reduced settings like 5 to 10 watts. Wasn't sure if there was some parasitic oscillation or anything going on. the power output looks steady on the wattmeter and the recieved signal in my 706 sounds clean.  

Would this happen to sound familiar to anyone?

Before I put the cover on I'm going to do as Don suggested and run through Wayne's alignment procedure on the 4mhz oscillator and display calibration to get that hopefully finalized (if I can RX WWV this morning that is ;)).

But all over but the shoutin' at this point ;)

Tnx es 73,
LS
W5QD

[lstavenhagen]

Oops, when I said bandpass filters, I mean only on 80 meters. All the other bands had very definite and loud peaks on recieve...

LS

[Don Wilhelm-4]

That is normal for the 80 meter bandpass - it is very broad tuning.  No
problem.
The 15 meter higher current thing is not likely a problem either - I
would guess that the max power level on that band is in excess of 14
watts, and if so, that is not a problem.  Turn the power down to 10
watts and check the current draw on each band.  At the 10 watt level,
the current should not exceed 2.5 amps if all is working OK.  If your
power supply is less than 13.8 volts, the K2 will draw higher current
than with the higher voltage - so make sure you have an adequate power
cable.  The wire may carry the current fine, but the voltage drop may be
too much with a small wire - I recommend 16 gauge although 18 gauge will
usually do OK.

73,
Don W3FPR

lstavenhagen wrote:

> Oops, when I said bandpass filters, I mean only on 80 meters. All the other
> bands had very definite and loud peaks on recieve...
>
> LS
>  
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 9.0.733 / Virus Database: 271.1.1/2683 - Release Date: 02/12/10 02:35:00
>
>  

______________________________________________________________
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

[lstavenhagen]

Ok thanks Don.
I ran through all the bands at about 10w and the current draw and output was pretty consistent everywhere, 2.2 to 2.4  amps draw. My power supply is a 12ah battery and it pulls down about a volt at max power which like you said will result in higher current draw. So looks like its normal to me at this point.
Went ahead and did the final assy., so it's all done and buttoned up. I just need a proper ant. now ;)

Before that tho I redid the 4mhz calibration, but just did the procedure in the manual to start with. Luckily I was getting WWVH audibly on 10mhz this am and zero-beated by using my 706 on WWVH on AM. I tuned the K2 until they both sounded as close to the same as I could get. Adjusted C22 as directed and redid CAL PLL and the filters. WWVH zero-beated now reads 10000.04mhz or thereabouts which I figure is close enough for me.

Sure enough, the reports of the receiver being outstanding are totally true. Strong sigs can be right nearby and I don't know they're there until I tune onto them. With my 706MKIIG, even S7 sigs blow through the 500hz filter like butter so I'm used to all kinds of intermod and noise. Seems all gone now with the K2!

Now having gone through it, I'd say it's not such a bad kit even for a first time kit builder like I am (was). It's so well laid out and clear that you can only make mistakes if you go too fast (like I was doing last night hi). I will also vouch for having the right tools, the good iron, small solder and small flush cutting wire cutters were the most essential tools for the whole thing.
It just doesn't give you any problems if you do it according to the instructions. Maybe a little bit of a letdown as I was sort of expecting it to be harder, but it really wasn't.

Anyway, have to wire up my bencher and put up a better wire now so I can get on the air with it!

Tnx es 73,
LS
W5QD