[NLRS] VHF low pass filters?

[kp hpjr]

Doug and others! WOW!
Mailbox loaded during the day.
Many great tips and ideas. 
Hope to be able to find articles on building simple filters or better yet find a 
source to purchase a few.
Tnx all info..
Kirk, N0KK
 
> 
> 
> Congratulations! Your question has raised the most activity I've seen
> here in a long while....
> 
> I agree with the others that it is most likely fundamental overload of
> a preamp or amplified splitter in the neighbor's house. It is unlikely
> to be harmonics of your signal. If he says the problem is only one or
> two channels, check for a harmonic match. It it occurs on all
> channels, it is simple RF overload.
> 
> A quarter-wave stub is the easiest option to test with, but it repeats
> the notch on the odd harmonics so it could suck out a real TV channel.
> A high-pass filter would be a better choice. Ideal would be to find a
> inline filter with F-connectors that passes everything above 85MHz.
> That will allow the FM band and all current TV channels.
> 
> I'd suggest try this first:
> <http://www.ebay.com/itm/Digital-Cable-TV-Box-Filter-CATV-HDTV-/261150112671?_trksid=p3284.m263&_trkparms=algo%3DSIC%26its%3DI%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D21%26pmod%3D130369229197%26ps%3D54>
> 
> The above is supposed to be a high pass filter that provides >40dB
> rejection of signals below 54MHz. It is made by Pico Maco as model
> HPFO 54MHZ. For $7 delivered, you can't afford not to try it. I
> ordered one just to measure it and see how well it works.....
> 
> I did go looking for a copy of the specs for the item. It is funny to
> see it has about 8 pages of installation instructions, and somebody
> asking how to install it. But the answer becomes more clear when you
> see the web page that talks about using it to block pay-per-view
> reporting on a cable system, and how to reset the PPV log inside the
> cable converter....
> 
> After checking the Pico Macom catalog page, I don't think its going to
> work. The catalog shows the filter corner starts at 54MHz and is 40dB
> down by 40MHz.So that probably will not help much.... But it is
> ordered and I'll be able to measure a sample next week....
> 
> In the mean time, you can use any RF filter design program to give you
> values for a simple high-pass filter starting at 85MHz with any amount
> of attenuation you want at 54MHz.
> 
> Good luck!
> 
> 73, Doug Reed, N0NAS.
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