Brian,
Do things settle down if you drive a dummy load instead of the antenna?
If so, that would nail it as an RF Feedback. If that is the case, use a
good quality common mode choke at the junction of the coax with the
ladderline. See K9YC's RFI information at
Brian,
The Elecraft K series requires a different way of setting power out on digital.
You increase the audio drive from the SignaLink until the "ALC" meter is
showing 4 to 5 bars and then adjust the power control to set the required power
out, do not use the audio level to adjust the power.
Brian,
Too early in the morning with me, I just noticed the fact you have a K2 not a
K3 or KX3.
In that case the ALC meter is different, but perhaps you may find something
that is helpful on the late G4ILO's site:
http://www.g4ilo.com/k2psk31.html
73
David Anderson GM4JJJ
> On 25 Oct
Don,
Yes, things settle down with a dummy load, so it looks like I'm dealing with
RF feedback.
Per the original post, I'm using an Elecraft BL2 balun at the
coax/ladderline junction. Shouldn't this act as the common mode choke that
you suggest or are you suggesting to place a common mode choke
My take on this is baluns are baluns and common mode chokes are common
mode chokes. In many cases baluns do not provide adequate common mode
choking requirements. Thus both may be needed. Usually, the balun is
located physically at the load and the common mode choke is located at
the source.
Yep, almost. The word "balun" is a portmanteau of "balanced" and
"unbalanced." They are transformers or auto-transformers and their job
is to keep a balanced feed to the antenna balanced when transitioning to
unbalanced coax. Since they're transformers, they can also transform
the
Brian,
The Elecraft BL2 is a good common mode choke. It is rated at 250 watts
into a *matched* load.
Your load certainly is not matched, and I do not know how to de-rate the
power for any given load.
Check to see if the balun core heats - if so, you could be operating the
BL2 outside its
Yes. And even more important -- the word "balun" is used to describe so
many (at least) ten different very kinds of components that the word
itself should be banned from our language. ONE of those components is a
common mode choke. Another is an array of common mode chokes. Another is
a
I'm having an issue with unstable power output using digital modes on 40m
above about 20 watts. All other bands seem to be ok.
My antenna setup is as follows: a loop consisting of about 245 feet of wire,
feed line consists of about 21 feet of 450 ohm ladderline to an Elecraft BL2
balun, then
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