[TowerTalk] Broadcast Band Filter

[jim.thom jim.thom@telus.net]

Date: Tue, 27 Feb 2024 09:46:12 -0500
From: "Mike Ryan" <mryan001 at tampabay.rr.com>
To: <towertalk at contesting.com>
Subject: [TowerTalk] Broadcast Band Filter


During the last 160m SSB contest it became obvious that I am in need of a
serious broadcast band filter.  Though I currently have one in-line that I
bought a dozen years ago (cannot recall what brand) I appear to be getting
some bleed through from 1420 AM. If only it were good music, or even bad
music. But the 'fire and brimstone' programs and subject matter are more
than I can take. Suggestions?  - Mike, K4CVL

##  What about a simple series LC filter...tuned to  1420 khz ?  For max
attenuation, you want high L, and low C.  Hot side of the coil goes to the
hot side of the coax.  Cold side of the coil goes to the hot side of the
cap.  Cold side of the cap goes to the shield / chassis.

##  Done correctly, that will kill 1420 khz.   The series LC filters work
good, but only one one frequency ( +/- several khz).  You can even parallel
2 x identical LC filters, and / or stagger tune em.

Jim  VE7RF