There is a way to block a single channel I don't want, but I can't remember what it is. It isn't an attenuator, because that alters the power throughout the entire line.

I want to experiment with blocking an analog channel that is causing adjacent channel interference.

What is the trick? I know it has been mentioned on here before.

You can buy a cylindrical notch filter like tha cable companies used to use for $20. They generally deeply notch the visual carrier frequency, but attenuate less than half the RF power of a digital channel.

What conflict do you face. Can you give us a zip code and and identify the two channels? There are ways to engineer "phase cancellation" into a two-antenna array, buyt they are difficult to implement.

My ZIP is 15767. I am trying to get UHF 24 (WATM-DT, out of Altoona, PA) and one of the theories is adjacent channel interference from UHF 23 (WATM analog). Also, I get a solid signal from UHF 25 (KDKA-DT, out of Pittsburgh, PA).

I talked to the station engineer about it and he suggested the adjacent channel may be an issue. To compound the problem (because why not) I also get near-solid reception of WVPX, UHF 23, an Ion station out of Akron OH.

I have a ridge line south of me that rises about 200' higher than my location. And there is also a 24 UHF digital out of Erie, PA but I do not believe it is causing any co-channel interference.

A two antenna array is not feasible with my current equipment, because I am using a CM 4228 with pre-amp. It would be a nightmare.

The general opinion I have heard from others is that the 23 analog of WATM is the worst culprit in this mess.

filtering is problematic with digital because the filtering process is not narrow enough to affect just 1 channel but also affects adjacent channels. if adjacents are not an issue then a filter would be worth trying.

Otherwise the compromise would be the appropriate selection of antenna, preamp and using a rotor to try to squeeze a better signal.

the 91xg may be an alternative over the cm4228 and a lower gain preamp to lessen adjacent channel interference.

Another thing that works is experimenting with antenna location and using physical blockage of sgsnal to attenuate the signal of the interfering channel. requires patience and does not always work to your benefit.

There are many variables associated with this issue and a challenge to address.

The CM 4228 has better gain than the XG91 at the frequencies you are trying to receive, so i would not recommend an antenna change. If you want to experiment with a notch filter, i would try www.tinlee.com. They make both fixed and tunable filters for off air frequencies. How is your reception of WATM analog and are they running their full licensed power of 1000 kW on their digital broadcast?

How is your reception of WATM analog and are they running their full licensed power of 1000 kW on their digital broadcast?

The analog is solid except for some very obvious signs of interference (many slightly visible solid, horizontal bars).

I wasn't very solid on the ERP with engineer, but from what I know about their sister station (which is a Fox station and their main station; WATM is second fiddle) it is actually operating 700kw despite being licensed for 1000. The company has a really bad reputation for not wanting to spend.

The signal strength reported for 24 is strong. The tuner knows there is a channel there, that's for sure. But it never even pulls in so much as PSIP data.

the 91xg may be an alternative over the cm4228 and a lower gain preamp to lessen adjacent channel interference.

I thought about that after reading on here more, but I'm not going to have time to screw around on the roof before the weather starts turning for the worst. If I had it to do over again I would have tried the 91xg first, but the CM 4228 got a lot of praise and I've done well with CM in the past.

Another thing that works is experimenting with antenna location and using physical blockage of sgsnal to attenuate the signal of the interfering channel. requires patience and does not always work to your benefit.

Already have, this is the best location on the property where I can get any height without building a tower.

My ZIP is 15767. I am trying to get UHF 24 (WATM-DT, out of Altoona, PA) and one of the theories is adjacent channel interference from UHF 23 (WATM analog). Also, I get a solid signal from UHF 25 (KDKA-DT, out of Pittsburgh, PA).

I talked to the station engineer about it and he suggested the adjacent channel may be an issue. To compound the problem (because why not) I also get near-solid reception of WVPX, UHF 23, an Ion station out of Akron OH.

I have a ridge line south of me that rises about 200' higher than my location. And there is also a 24 UHF digital out of Erie, PA but I do not believe it is causing any co-channel interference.

A two antenna array is not feasible with my current equipment, because I am using a CM 4228 with pre-amp. It would be a nightmare.

The general opinion I have heard from others is that the 23 analog of WATM is the worst culprit in this mess.

I plugged in your zip code into TVFool and Antennaweb and nearly all of your stations are very weak. TVFool shows all your stations as 2 edge or tropo except for channel 3. It seems unlikely that adjacent channel interference is your problem.

The "signal strength" meter in all TVs that I know about is actually a signal quality meter which means it's basically telling you what the signal to noise ratio is. The S/N can be fairly high even if the the signal is relatively weak as long as the multipath is low. I know on Sony TVs that the AGC number on the diagnostic screen is actually a real signal strength meter except it's read in reverse, the stronger the signal, the lower the number.

You probably don't have access to a spectrum analyzer but that would tell you for sure if the problem is a weak signal.

I plugged in your zip code into TVFool and Antennaweb and nearly all of your stations are very weak. TVFool shows all your stations as 2 edge or tropo except for channel 3. It seems unlikely that adjacent channel interference is your problem.

TV Fool is very off. I have to set it to a height of 100 feet to replicate my actual reception.

AntennaWeb is even worse.

TV Fool is very off. I have to set it to a height of 100 feet to replicate my actual reception.

AntennaWeb is even worse.

Okay. I did a little more research and I see that you're trying to receive WATM-DT which is right next to WATM analog. Normally this should not be a problem. Although the signal strength predictors are often in error (in both directions BTW), TVFool says you have a 2 edge path and that's likely to be correct since your antenna needs to be 500' for LOS. 2 edge paths are tough and often suffer from multipath problems. I know because all my local stations are 2 edge. It's not an impossible situation but the signals wll be much weaker than if they were LOS at the same distance.

I went to the FCC database and brought up WATM. You are nearly in an antenna pattern null for WATM-DT so this alone will make it much weaker than if you were in the main lobe as you are for WATM analog. Also the digital antenna is lower on the tower than the analog antenna which probably means it is side mounted. If the tower is between you and the antenna then the signal could be much weaker than indicated by the antenna patterns. Hopefully all these side mounted antennas will get on the tops of the towers by the transition date.

So despite what your signal quality meter says, your actual signal strengths are probably not very high. Without a spectrum analyzer it's impossible to know, but your problem is probably too weak of signal or bad mulitpath.

And it doesn't matter that all the other stations are fine. I just did an OTA setup for my cousin only 17 miles from the transmitters, line of sight except for a row of eucalyptus trees down the street. How easy can it get? All signals were fine except one that was unreceiveable. I put my analyzer on the antenna and that signal was being destroyed by mulitpath.... the trees!

I live in Pennsylvania. Trees are like green rats around here.

If we're talking about multipath, shouldn't I see ghosting in channel 23? I don't.