[RFI] RFI With Smoke Detectors

Greg Troxel gdt at lexort.com
Fri Aug 21 11:31:30 EDT 2015


Jim Brown <jim at audiosystemsgroup.com> writes:

> That OCF antenna, by virtue of its imbalance, puts a LOT of common
> mode RF current on the feedline, which penetrates what you THINK is a
> Faraday cage (and it's NOT a Faraday cage unless the metal completely

Have you tested/evaluated the RadioWorks T-4G+ line isolator, or the
similar things from MFJ?  I know you recommend many turns around
specific mixes, but I'm curious what the shield impedance is on these.

I have a T-4G+ and when I insert it just before the radio with a coax to
an attic fan dipole, received noise gets better.  I think that's due to
reduced pickup from sources closer to the feedline than the antenna
elements.  In my Copious Spare time I should measure the choking
impedance at various frequencies.

73 de n1dam


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