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From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.design
Subject: Re: Filter problem
Date: Sat, 14 Jun 2025 09:31:55 +0100
Organization: Poppy Records
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Dave Platt <dplatt@coop.radagast.org> wrote:

> Is there any chance you can make enough room in your setup for
> something of the following sort?
> 
> https://www.pa0nhc.nl/IMDfilter/EN/Notch/Single/HelicalNotchfilters2mEN.htm

That's exactly the sort of thing I had in mind.  The author's dimensions
of 4" diameter and 6" high might be a bit of a problem but I could try
scaling it down and adding more turns to the helix.  Perhaps a piece of
35mm copper pipe would make a good starting point.

A length of thinner pipe would be easier to accommodate, so perhaps I
could experiment with something intermediate between between a coaxial
stub and a helical resonator.

-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk