Do i have a chance?
 

Hi, in need of a little advice on reception. My tvfool report:

http://www.tvfool.com/?option=com_wr...b97d569f846710

The goal is to get CHAN-DT channel 22. Seeing that is a negative 3.9 dB i just don't know if i should even bother with spending $$ on a antenna. I bought a cheap digiwave 4 bay and was able to get 21, 27, 29, 23, 35, 19 and 24 with the antenna outside leaning against my fence. When aimed 15 degrees (me holding it) i cannot get CHAN channel 22 with the digiwave. I can mount an antenna properly on my roof aprox 20 feet up and have clear line at 16-17 degrees. Some trees at 15 degrees. Coaxial cable will be 30 feet max to tuner..do i have a hope with a proper antenna like the Db8e? Or is channel 22 just to weak?

Cheers
Shaun

I think what is the main issue is that the 2 channels immediately either side of it (21 & 23) are ~65dB more powerful at your location & the co-channel interference would preclude it coming in.

Wiser heads than I will chime in too.

tonyp063 is correct, 21 and 23 are causing a serious problem for 22, but it is called adjacent channel interference. Co-channel interference would be from another transmitter on channel 22, like a much weaker KCPQ Fox with a NM of -23.3 dB.

TV tuners are not required to tolerate adjacent channel interference greater than 33 dB.

The only possible solution would be a separate antenna, preamp, and a custom single channel bandpass filter for real channel 22 from Tin Lee Electronics. Even they might not be able to design a filter that would work. You could call them and email your tvfool report. The filter would be more than $100.
http://www.tinlee.com/index.php
http://www.tinlee.com/bandpass_filters.php?active=3#CF7

Yeah. That's what I meant. Thanks for catching that.

Thanks for the advice. I was worried it looked unlikley but at least i now know

In order to reduce the interference you could select an antenna with a null at 123 degrees to reject 21 and 23. The popular DB8e is about 23 db down at 123 degrees at those channels. (the 91XG is similar) That's leaves about 14 db to filter out with a Tin Lee filter. The extra 14 db could also be achieved by placing the antenna on the side of the house so that the angle toward the stronger 21 and 23 is blocked by aluminum siding, foil backed insulation, or some other RF opaque material.

A pair of 91 XG's stacked horizontally and spaced 42" apart could also get channel 22. http://www.hdtvprimer.com/antennas/ganging.html

Would there be an alternative to the 91xg? I was looking at the specs and they are over 90" long. I was planning on installing setup on my garage wall pointing to 16 degrees. The issue is the 90" 91xg would cross over into my neighbors property. Is there another antenna that might also work when ganged as you suggested?

As mentioned by Tower Guy, the DB8e might work as well as the 91XG, and it is a panel antenna that wouldn't stick out as far.
The separate DB8e would need to be mounted in a location that shields it from the signals from 21 and 23 and have a clear path from the 22 transmitter without trees or other buildings in the way. Both panels of the DB8e must be aimed at 15 degrees true/358 degrees magnetic.

It would help if you can show us some photos of the mounting location, or send me the coordinates of the antenna location by PM so that I can look at the green signal lines on the tvfool interactive map browser.

I see a lot of trees in your area.

thanks for the reply. I do have a few trees around! I have attached a copy of your pic with some details that may help. When standing on a ladder next to my planned location I get a clear line of sight above roof lines etc of neighbors sheds and roofs. At work right now but will try to snap a pic from the ladder pointing towards channel 22

Would a pair of 43 XG antennas stacked 42 inches apart hang over your neighbors?

they would just cross over. The advantage I have is the neighbor in question has a shed that would block their view of the antenna's. So if it hangs over a few inches I am not worried so much. with the 91xg's they would hang over a couple feet.

Thanks for the image with the notes. This is what I wanted to do:

http://forum.tvfool.com/attachment.p...4&d=1452025887

I deleted the numbers after the decimal point in the coordinates for your protection and increased the height to make the CH22 green line easier to see.

You ARE on the CH22 fringe, but a -3.9 NM can be compensated for by antenna gain. The biggest problem is interference from strong local signals. The FB/FR ratios of the antenna can attenuate the strong locals to some extent, but there will still be reflections from the strong locals off objects in front of the CH22 antenna.

The terrain causes a lot of interference to the signal.
http://www.tvfool.com/?option=com_wr...ALLTV%26n%3d12

very helpful info thank you all. So I am summarizing here but it looks like a potential long shot to get this to work. If I go with 2 - 43XG's and a tin lee filter I am in for about $250. 2 - 91XG's and the tin lee filter put my at $300. I know there is lots of variables but in your opinion is this cost worth the risk of spending the cash and not getting the signal strength needed? and if it worth the risk should I go with the 91XG's vs 43XG? would the bigger antenna really make a big impact given this scenario?

again, really appreciate all your thoughts and help

Only you can decide if the gamble is worth it.

The tvfool report is only a computer simulation, and is often not too accurate with 1Edge and 2Edge signals.

If you talk to a Tin Lee engineer and email your tvfool report to him he can give you an idea of the odds.

As a test you could try your present antenna in the new location. The signal wavefront is rarely uniform, and a small change in antenna location can make a big difference. Antenna installers call it "walking the roof." To say it another way, the best location for the antenna isn't always where you wanted to put it.

I'd try the pair of 43XG antennas without the TinLee filter first and then add the filter if necessary. However, Rabbit73 is right, reflections may minimize the interference advantages of the stacked antennas, but the actual amount of the interference is hard to predict.

FYI, the 43XG has been discontinued and we are out of stock. All remaining inventory is out there in the distributor's warehouses and, when they're gone, they're gone.