[Elecraft] K2/100 Flat topping on 30m?

Thu Oct 31 10:32:00 2002

Hi

One more thing you may want to try. Wayne mentioned adding a ground strap=
 from the shield to one of the screws on the SO239 connector may be neede=
d to suppress oscillation in some cases. Just install a terminal lug at t=
he connector and solder a short wire from the shield to the lug. It may n=
ot help but it is easy to try. I will make the measurements on R26 you re=
quested. I have 3 K2/100 in house at this time so I can get the values on=
 all of them. I will measure the resistance from end to the wiper and the=
 ALC voltage at the wiper at 100 watts if you think this will help

Don Brown
KD5NDB

----- Original Message -----
From: [email protected]
Sent: Thursday, October 31, 2002 7:53 AM
To: Don Brown
Cc: [email protected]; Jim W7RY; Elecraft
Subject: Re: [Elecraft] K2/100 Flat topping on 30m?

On Thu, 31 Oct 2002, Don Brown wrote:

> Hi
> =20
> I don't know if this is your problem but I had this come up in the
> KPA100 field test to the one I built. If R26 is set too low 30 meters
> would draw a lot of current at high outputs. I was getting up around
> 25-30 amps at 100 watts out. Other bands were not as high this only
> affected 30 meters. If this is the case you may be overloading your
> power supply and the voltage is dropping. Have you monitored the
> supply while transmitting to see if it is well regulated. The R26
> problem was due to setting the power calibration at 5 watts rather
> than 50 or 100 watts. When setting the calibration that low it is easy
> to be off by a fair amount at 100 watts. R26 sets the ALC feedback so
> it can cause strange reactions if not calibrated properly.
> =20
> Don Brown
> KD5NDB   =20
> =20

Don,

I'd lean towards this not being a calibration issue.  After I finished th=
e
KPA100, when I was seing ALC problems with SSB on _all_ bands, I sent the
rig to Gary who found that the problem was a 1/2 installed PSK mod on the
KSB2. (Don't ask me.  I installed the resisters and caps that were
supplied and they fit what the manual said.)  Anyway, Gary also aligned
the rig, set up the filters, etc.

I will take a look today though and see what I can find.  I'm wondering i=
f
you can provide me a point of reference?  What is your R26 set to?
(measured between which two points?)

Thanks,

73 de John - KC4KGU
K2/100 #2490

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