Marv & all,
Just some random thoughts which may or may not be appropriate/valid:
Why 1-2 mH? Just curious because if I had a choke design that was
250-300 MICRO H and didn't have any resonances below 30 MHz I would be a
very happy camper.
Several years ago there was a discussion on this list regarding ferrite
used in plate chokes. I don't remember all of the conclusions but I do
remember some examples in commercial TX's. Seems like they used a
rod/slug *partially* inserted into the solenoid choke.
Re the referenced web page, seems like there are some errors there but
the end result looks interesting. I would like to measure one of those
myself as I don't trust most guys to get it right.
Having tried the grid dip meter approach myself, I found that was a good
way to wind up with all the magic smoke escaping the choke in question.
Just today while measuring the loaded Q of a pi-net in the latest amp
project, I was able to see and read out the choke resonance to within a
kHz or so while actually in the sealed up amp and tuned to 10/12 meters.
I use a VNA for this but can and have used a sig gen and spectrum
analyzer with equal success.
My normal solution to the choke problem is the restrict the number of
bands the amp covers. Mono-band amps are the best!
73, Larry
Larry - W7IUV
DN07dg
http://w7iuv.com
Radio WC6W wrote:
> Hi Angel,
> The point was to make a rather high value (1-2mHy) choke with no resonances
> in the HF region.
>
> The saturation gotcha was a by-product.
>
> A rod wouldn't suffice in this application. A gapped core might. The gap
> would need to be only a few thousand's wide and I don't have a diamond saw
> like that... Too bad pot cores aren't made in 43.
>
> 73 & Good morning,
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