Hi,
In a recent posting I mentioned I was not happy with the AGC action of
the K1 after pulling it out of retirement for a QRP Sprint on this weekend.
This is an account of what I consider, improves the set generally. I claim
no originality for the ideas, and any K1 purists or designers might like to
switch to the next message right now! ( Definitely YMMV)
The AGC "problem" of giving a burst of audio when a strong signal made
itself present was cured 99% by altering C31 to 1uf ( from 2.2UF) and
replacing C67 with a .22uf cap ( was also 2.2uf) That sped up the AGC
action and after using the set in the first 1/2 of the Sprint last evening,
I was more than happy with the AGC.
However....probably being spoilt by the K2, I found the tuning rate a tad
delicate for my fat fingers, and the RIT action was gross.
OK.....I know it has a large range so the set can be used in SPLIT
mode....but I doubt I will use that mode on the K1, so I looked in the
Elecraft Reflector listings and dug out a solution posted on 20 Jul 2001
under the heading "Re: K1 RIT mod", where the RIT is modified to a
logrithmic action that gives a small range of tuning over about the first
25% of the controls throw, ( each side) but still retains most of the
original total range.
It was a tight fit getting the parts in and I had to use 1/8w resistors to
obtain a decent fit, but it works fine.
Now the VFO band spread. I was using the 68pf cap for C2, which gave me a
80khz tuning range. I altered C2 to 47pf and added an extra turn on L1 ,
and that gives me a tuning range of 51khz. A wee bit under the 55khz we are
allowed here, but perfectly acceptable to me.
The second half of the Sprint event is on tonight, and I am looking forward
to joining in with my "re-Vamped" K1 . From using the set last night, there
is certainly nothing wrong with the K1's receiver. I had forgotten what a
fun set it is.
Cheers.......Ron ZL1TW
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