[K2] K2 # 7841 is working

[aj4tf]

With some assistance from Don, W3FPR, K2 # 7841 assembly has been completed
successfully.

I found that the J310 FETs that came with the kit were slightly too slow to
make the synthesizer operate. Apparently this is an issue with the latest
batch of J310s.  There's a couple of solutions for this:  (1) install a 10
pF cap between the source and ground of Q19 or (2) use a different J310.   I
tried both solutions, they both worked.  In the end I elected to source some
J310s from kitsandparts.com which were an older vintage, and it worked fine
without the extra capacitor.

I also found that the trimmer caps for the 10m/12m bandpass filter (C44,
C46) were very touchy;  I thought for a while that 12 meter TX was not
working, but I finally got them tuned up so that I had good output power on
12m.  

I built # 7006 about 9 years ago (which is still working well), and was
really wanting to do another one,  so I went ahead and ordered it while we
still can.  

73, David AJ4TF






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[Dave Sublette-2]

Congratulations David,

For those of us who build, there is nothing quite like the thrill of seeing
something we have built come to life for the first time!  I hope to hear
you on the air.

73,

Dave, K4TO

K2 and KX3 owner

On Wed, Sep 19, 2018 at 12:45 AM aj4tf <[hidden email]> wrote:

> With some assistance from Don, W3FPR, K2 # 7841 assembly has been completed
> successfully.
>
> I found that the J310 FETs that came with the kit were slightly too slow to
> make the synthesizer operate. Apparently this is an issue with the latest
> batch of J310s.  There's a couple of solutions for this:  (1) install a 10
> pF cap between the source and ground of Q19 or (2) use a different J310.
>  I
> tried both solutions, they both worked.  In the end I elected to source
> some
> J310s from kitsandparts.com which were an older vintage, and it worked
> fine
> without the extra capacitor.
>
> I also found that the trimmer caps for the 10m/12m bandpass filter (C44,
> C46) were very touchy;  I thought for a while that 12 meter TX was not
> working, but I finally got them tuned up so that I had good output power on
> 12m.
>
> I built # 7006 about 9 years ago (which is still working well), and was
> really wanting to do another one,  so I went ahead and ordered it while we
> still can.
>
> 73, David AJ4TF
>
>
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

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