Glad you got it working. I've assumed that, since the K2 is a kit in
which you build the case with pieces around the electronics, it is
really important that they all bond well. Especially true at 100 W.
Yes, Jim's research and publications are the go-to source for
On 2021-09-04 19:14, Jim Brown wrote:
I'm the guy that did the original work on this, beginning in 2003,
Wow. From the horse's mouth, so to speak. I am reading the paper.
Thanks, Jim!
In addition... on the side panels, I removed the paint at each and
every screw attachment point,
using
I've found preferred method for evaluating Ferrite Choke Balun common
mode rejection performance is to measure common mode rejection (CMR).
Some various 43 material examples, which demonstrate CMR is a function
of device inductance.
https://www.kn5l.net/Balun-CM/Balun-43material/
FT140-43 7T CMR
On 9/4/2021 2:48 PM, jerry wrote:
31-mix is supposed to be the hot ticket for HF common mode
chokes. One turn through one core is supposed to be 98 ohms at 5MHz. So
four cores should give me about 400 ohms, which should give a worthwhile
attenuation in a 50 ohm system. Thanks for the
Jerry,
It sounds like some RF from the KPA100 could be getting into the base K2.
Is your KPA100 upgraded with the latest updates, AND the new shield?
For the latest update, peek between the shield and the board - If you
see blue toroid cores at RFC1 and L16, then it is up to date - OTOH, if
Jerry,
As I understand it, about 5000 ohms is a goal when deploying common mode
chokes. Hence why K9YC says multiple turns through a core is needed. Sometimes
multiple cores in series.
But as I read you email, I think I’d focus on what’s different or amiss with
the K2 since the other rigs
Jerry: Make sure your amp "lid" is securely bonded to the base K2. I
have an early K2 and had the same kind of symptoms as you did when I
added the amp lid. I finally traced it to significant paint over spray
on the K2 side panels. I ended up sanding them clean and the problem
disappeared.
On 2021-09-04 14:31, Jim Brown wrote:
On 9/4/2021 2:03 PM, jerry wrote:
I made up a short length of RG8/U with 4 Palomar 31-mix giant ferrite
beads
Palomar SELLS these cores, at high prices. Fair-Rite MAKES them.
31-mix is supposed to be the hot ticket for HF common mode
chokes. One turn
On 9/4/2021 2:03 PM, jerry wrote:
I made up a short length of RG8/U with 4 Palomar 31-mix giant ferrite
beads
Palomar SELLS these cores, at high prices. Fair-Rite MAKES them.
- a common mode choke. No difference.
This is only a good choke at VHF. If your problem is HF, multiple turns
must
Hi Elecraft list & Bob,
Sigh. Sometimes it don't pay to get up in the morning.
First, I was having a CW QSO on 40M with a station in the East Coast...
My K2/10 was driving the Tiny Linear - we were seeing 150W on the meter.
Suddenly, the screen of the linear flashed bright white, and the RF
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