Channel Blockers?

fsphil

Evening everyone, and happy new year.

I'm in Mid-Ulster, receiving BBC, Freeview & RTE nicely. I'd like to add my own signals to the system (a computer-PVR and CCTV) but I'm having problems finding enough free channels for the RF modulators - there are faint signals on many of them that prevent me using them. I've spent a few hours googling and found a few references to 'channel blockers'. Could I use these to clear the channel for my own use? And if so, where can you buy them? I can't seem to find them anywhere!

First post here, hope this is the right forum - if not please ignore :-)
-Thanks,
Phil

byte

Hi fsphil, and welcome to boards!

Yes, you're in the right category!

What I think you are looking for is what I know as "notch filters" which basically filter out single channels (though they sometimes attenuate adjacent freqs too).

Not sure where you can get them though.

Ulsterman 1690

Theres a place in England does them. Do a google search for "Taylor Bros" in Oldham theyre mostly geared to supplying the trade but will sell mail order to anyone.

They have a website although it can be hard to find

fsphil

Hi byte and Ulsterman,

Notch Filter, that's it! Armed with the proper name and google I found JW Hardy selling them (http://www.jwhardy.co.uk/shop/pages/pl_filters.html) for £19.95. Bit more expensive than I'd expected.

Ulsterman's pointer to Taylor Bros brought up something interesting, they sell a "Single Channel Combiner" for about the same price which might be more suited for the job. They also have the Notch Filters for half the price.

I've gone from no idea to multiple choice, thanks both!
-Phil

watty

That is cheap. Good Helical filters for channel pass and filters for blocking can run to £40 or more per channel.

An attenutor in aerial feed increased till wanted channels are OK and unwanted vanish coupled with a roof Yagi selected for group and adjusted direction can be cheaper. I use a higher group Yagi and attenutor of 12dB to reduce all the channels from 21 to 38.

Extra coax in aerial feed will reduce Ch55 to Ch68 more than Ch21 to Ch49 also for example. (About 25m is a start!)

fsphil

watty wrote:

An attenutor in aerial feed increased till wanted channels are OK and unwanted vanish coupled with a roof Yagi selected for group and adjusted direction can be cheaper. I use a higher group Yagi and attenutor of 12dB to reduce all the channels from 21 to 38.

Hmm... interesting, I could use a bigger aerial as BBC Two and ITV are a tad fuzzy. I have a wideband at the moment, would it be better to get a Group K aerial or a higher gain wideband? Group K aerials seems quite rare.

watty

Wideband makes problem worse.