[Elecraft] K2/100 CW Problem

Sat Oct 11 22:04:00 2003

I'd like to second David's comments.  The first dit should attain full power
without hesitation.  My K2 keys flawlessly.  At least that is one thing to
add to the "plus" list on this radio.  I only wish it was full QSK, though.
That is missed sorely, particularly working pileups and for multistation
contacts/chats.  It is way too complex an issue for me to try to figure out
how to implement Transmit/receive switching in between character elements.
So I guess I'll keep missing QSK.

It almost sounds as if there is some kind of capacitor misload on amplifier
ALC that causes a slow rise/fall time on power control.  I'm not really sure
how to troubleshoot that one.  VRFDET appears to feed pin 2 of the Control
Board MPU directly through an 820 ohm resistor R12.  What the heck, check
R12 to see if it's really 820 Ohms!  You might want to check some capacitors
and their associated resistors on the power amp board in the detector
circuits, like C65*, C63, C70*, C71.  The capacitor numbers I starred can
have a dramatic effect if they happen to be off a couple orders of
magnitude, like 0.1uFd instead of 0.001 uFd!  All the suspect circuitry
appears to be on the right side of page 61 of my KPA100 manual.  Check
values, loading and solder.

I think that's the best I can offer without additional info.

It should NOT work as Rick describes.  It should key just as well as my
Kenwood 950 or the TenTec Omni.  At least that's my experience.

Bill
NA7Y

----- Original Message ----- 
From: "David A. Belsley" <[email protected]>
To: "WQ8Q" <[email protected]>; <[email protected]>
Sent: Saturday, October 11, 2003 6:21 PM
Subject: Re: [Elecraft] K2/100 CW Problem

> Rick:
>   I am 100% cw (and do a lot of it) and never notice any difficulty due to
> the K2's finding its power level; it occurs almost instantaneously.  And
> once achieved, you should have no further hesitation until you change
bands
> or restart the K2, even if you change the power request. Indeed, the
> ability of the K2 to change power (over its entire range) on the fly is
> quite remarkable. I have worked dozens of K2 ops on cw and this has never
> been an issue. So, if your K2 takes appreciable time in achieving the
> requested power level, or does so repeatedly during the qso, there is
> something wrong with your unit.  My suggestion would be for you to use
your
> K2 as if nothing were happening, and I suspect you will find that to be
> true.
>
> best wishes,
>
> dave belsley, w1euy
>
> --On Saturday, October 11, 2003 5:27 PM -0400 WQ8Q <[email protected]>
> wrote:
>
> >
> > Many have said, in response to my question:
> >
> >> Rick:
> >>   This is almost certainly not a problem.
> >
> > Well, geez . . . I've spent $1300+ on a radio with a great receiver,
> > mediocre audio output, had to buy a fingerdimple for easy tuning,  and
> > now I find that you have to prime it (like an old water pump) to send
> > CW???? Makes me long for my TenTec Omni V . . . I had fun building the
> > K2, but it does leave something to be desired . . . hope this doesn't
> > upset those who believe Elecraft is the holy grail of ham radio . . .
> >
> > 73 de Rick, WQ8Q
> >
> >
> >
> >> > Noticed a problem with my K2/100 today, while checking out the FISTS
> >> > Sprint. First time I've really played around with CW other than
> >> > occasional ragchew since I built the rig.  I noticed it takes several
> >> > "dits" before the K2 shows any RF out.  Like it has to "build up" to
> > full
> >> > RF out.
> >
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>
>
> ----------------------------------
> David A. Belsley
> Professor of Economics
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