Topband: Help with RFI

[Tom W8JI]

I'm reposting this to the reflector:


> Yes,  I do have DSL. I have a very good RFI filter on the DSL line coming 
> to the modem so I think it might be a cabling problem. Everything was 
> working FB until recently when I reconfigured the hardware.  I have a few 
> clamshell filters and I also have some shielded cables so Monday I will do 
> some substitutions and see if it helps.  The problem is not across the 
> entire band. It's only below 1825.  Frequencies above 1825 don't bother 
> me.

This is probably 160 meter RF triggering the modem. Common mode chokes and 
shield normally will not do the trick, because the problem is differential.

First, you need an immune modem. The best modem I found was a 2wire ADSL 
modem.

Second, filters are almost impossible to buy. Because of that, I built my 
own filter. I added peaking at the high end of DSL, which for ADSL ends in 
the upper middle AM broadcast band area.

http://www.w8ji.com/adsl_filter.htm

73 Tom