Combining Antennas- Notch Filters?

[cpalmer2k]

I'm hoping to find some expert guidance from some of you on my OTA situation. I'm trying to combine two different markets (from opposite directions) using two antennas. My primary antenna (w/Pre-Amp) is pointed at the Charlotte, NC market and receives all its' stations. My secondary antenna will be an attic mount, hopefully without a Pre-Amp, or with a very low grade one (as all stations should be "green" for me) to pull in the GSP stations. I realize combining those into one cable has its' problems, so my question is this... can you get custom "notch filters" for multiple channel RF frequencies or would you have to use a separate filter for every channel?

Attached is an image of the channels I'm working with. I know I can easily filter out the VHF channels from the opposite antenna, anyone have any suggestions on filtering the rest on their respective antennas?

 

[ray224000]

My current OTA setup is aiming at two different markets. I have two antennas aiming south toward Dallas/Ft Worth which handles all UHF and VHF. I have a problem picking up a couple of the low power stations but for the most part I get what I want. They come and go as they please.

Just for kicks, I have a VHF antenna pointing north to Denison/Sherman area. I am able to pick up another CBS, NBC and METV.

I have these connected with a 3 way combiner, also using a pre-amp.

Before the the digital changes in 2009, I could also receive another ABC from the Ada area. It changed to UHF after the change.

Since I do not have any RF frequencies competing, I do not have any issues with the way it is set up.

 

[boba]

I'm hoping to find some expert guidance from some of you on my OTA situation. I'm trying to combine two different markets (from opposite directions) using two antennas. My primary antenna (w/Pre-Amp) is pointed at the Charlotte, NC market and receives all its' stations. My secondary antenna will be an attic mount, hopefully without a Pre-Amp, or with a very low grade one (as all stations should be "green" for me) to pull in the GSP stations. I realize combining those into one cable has its' problems, so my question is this... can you get custom "notch filters" for multiple channel RF frequencies or would you have to use a separate filter for every channel?

Attached is an image of the channels I'm working with. I know I can easily filter out the VHF channels from the opposite antenna, anyone have any suggestions on filtering the rest on their respective antennas?

What do you want to filter out?

 

[cpalmer2k]

On the secondary Antenna I need to filter the "main" channel signals and vice versa on the main.. I need to block the channels coming from the secondary antenna so the backside versions don't cause interference. I know the vhf channels are easy, it is the others I'm concerned about.


Sent from my iPad using Tapatalk HD

 

[Titanium]

Narrow and wide notch filters are available, but they are expensive and will have insertion loss. Maybe first try phased / combined antennas to verify you need to filter?

 

[primestar31]

Why don't you simply combine antennas using an A-B Switch? One side will have your main antenna, and the other side will have your off-axis stuff. It's a bit messy if you wanted to automatically dvr stuff all the time when you aren't around, otherwise should work well.

Notch filters and things like that should be absolute LAST resort. They typically have extreme insertion loss in general, so if your channels are close to threshold, you'd be wasting your time.

My first thought would be to just try a simple combiner, and combine both antennas on the mast after getting them tuned up/peaked separately. It MAY work acceptably for you without extreme measures. You can't know until you try at your location with your antennas and such. OTA reception is always voodoo when you want to do stuff like this, and you simply have to play with it to find your working combination.