Installed new 91XG today

[bjs81]

Hello, to begin with, heres my tvfool TV Signal Analysis Results:
http://www.tvfool.com/?option=com_wr...f1f09c07e55d67
my last posts were in 2012, I have lived with the same reception since that time. http://forum.tvfool.com/showthread.php?t=12720
I have had a Winegard CA-8100 with a AP-8275 pre-amp since 2001. My reception has been good 80% of the time, with the worst reception being in the heat of the summer, or fog, or low storms. All this last winter, reception was 99% good, but recently it has gotten bad where I felt it was time for a new antenna. After much research, I ordered a Antennas Direct 91XG with a Channel Master CM7777 pre-amp. Today I got it installed and so far I feel its going to be worth the cost and effort. But only time will tell to see if it will give me occasional bad reception.
After scanning for channels tonight, I am getting all channels on the list down to 28.1 with the rotor pointing the antenna to heading 342(Chicago), except ch 2.1 and 22.1. I am also getting ch 34.1, 66.1, and 20.1. I can get 22.1 and 46.1 if I turn it to Azimuth 45(South Bend). The one thing that I am thrilled with is I get ch 18.1 which is broadcast on ch 11, with the antenna pointed in either of the above mentioned directions, even though the statation is at Azi. 142. And the 91xg is uhf only.
Now for my question. I installed the 91xg, but left the CA8100 completely operational. and I installed the 91 xg 80 degrees off where when it is pointed at 45 degrees, the CA8100 is pointed at 342 degrees. I am thinking I would like to hook both antennas with their pre-amps into the main cable that feeds my TV's. Do I need a special "TEE" to do this? Also, is there a problem with what I want to do? I want to do this so we dont have to turn the rotor to watch either set of stations from 45 or 342.
Well I think I gave you all the information you need, if not, I will answer your questions as they come. Here is a picture of my antennas. BTW, that dish is for wireless internet.

[GroundUrMast]

The 'tee' you're looking for is simply a standard passive 2-way signal splitter. When connected in reverse, it can act as a signal combiner. The problem most folks run into when trying this is that both antennas will receive some signal from directions other than to direction they're aimed at. When combined, the desired signal from one antenna may be aided by the other antenna... But only if the signals from each antenna arrive at or nearly in phase. If the signals are out of phase, then the net effect is a form of interference. You can try adjusting cable length on one of the lines between an antenna and the combiner... This alters the phase of all signals arriving at the combiner.

The bottom line is that it's a relatively inexpensive experiment that usually provides an unpredictable set of mixed results. Some signals will be fine while others are less reliable. Most folks end up with a spare 2-way splitter when they've given up trying to find a perfect combination of aim and coax jumper length(s).

Here's an alternate method to consider: http://forum.tvfool.com/showthread.php?t=2882

[bjs81]

gggrrrrrr .... I did a search on the net after I posted here and found out that what i want to do normally does not work out. If I could just be able to pull in CH 2.1 (cbs), I could leave the antenna pointing in one direction. Instead I have to watch CBS on ch 22.1 from the other direction. I dont understand why I cant get ch 2.1 when it is so high on the list. But it is broadcast on ch 12 and only at 8KW, but then why does it show a signal of NM(db) .3 and I cant get it when I can pull in ch 20.1 that shows a signal of NM(db) -14 ???

[GroundUrMast]

The VHF performance of the 91XG is quite poor relative to it's excellent UHF capability. In weak signal conditions such as yours, the 91XG can't be expected to offer reliable reception of any real channel ranging from CH-2 to CH-13.

The CA8100 on the other-hand, is quite capable in the real channel 2 through 13 range. Have you considered pointing the CA8100 at 142° magnetic? Reception of real CH-11 should be fairly easy for the CA8100. Presuming that's successful, point the XG91 at 346° magnetic to receive the UHF (real CH-14 and up) signals. Combine the two antennas using a UHF/VHF combiner. The UHF capability of the CA8100 would be blocked by the filters at the VHF input port on the combiner and any VHF signal sneaking in via the 91XG would be stopped by the filters on the UHF port of the combiner.

The antennas Direct EU385CF is one example that also includes a weather resistant housing. http://www.amazon.com/Antennas-Direc.../dp/B008PBTPN4
Solid Signal sells a functionally similar product with no housing. http://www.solidsignal.com/pview.asp...zhyBoC72Lw_wcB

Radio Shack might still have some UHF/VHF combiners in stock... If their doors and windows aren't boarded up yet.

[bjs81]

I agree with everything you say, but i have 1 arguement. I have read that the 91xg can pickup the higher vhf bands, but is not rated for them. I can vouch for this as I am receiving ch 18.1 which is broadcast on ch 11. So if I can pulled 18.1 in, why cant I pull in one channel higher, 2.1 on 12? Also, I am pulling in 18.1 with the antenna pointed almost 180 degrees off of the direction 18.1 is broadcast from. SO accually right now I am able to get all the channels I want with just the 91xg, but I am sure the first time the conditions are not just right, I will loose 18.1, which is the channel I watch the most.
But what you suggested will be my solution, so thank you for that.

[GroundUrMast]

My 91XG can 'hear' some H-VHF... but the quality of the signal is quite compromised based on the signal measurement capability that's available to me (primarily the utilities that are provided with my SiliconDust HDHR tuners). An Antennacraft Y5713 is far more suited to H-VHF reception, but you would expect that, given it's designed specifically for that purpose. When you consider that there's a difference of 15 dB between the signal on real CH-11 and CH-12 and that the best of those two signals is roughly 30 dB lower than the nominal level a typical tuner is looking for, it's no surprise that the incidental VHF capability of a UHF only design can't deliver real CH-12 at your location.

Looking forward to your results... I'm expecting the CA8100 to provide far more success in the VHF band than any UHF only design can.

Cheers

[Tower Guy]

Originally Posted by bjs81

I have read that the 91xg can pickup the higher vhf bands, but is not rated for them.

Believe only half of what you hear and less than half what you find on the Internet. Those with luck receiving VHF stations with a 91XG have such strong signals that poor antenna performance didn't matter.

[bjs81]

Just fyi, the CA8100 never has been able to pull in ch 2.1 with any reliablity. I really feel that the signal strength of this station should put the station a lot lower on the results page. According to tvfool, it is only broadcasting at 8kw, where all the other stations around me are broadcast at 266 kw to 1000 kw. Channel 18.1 is broadcasting at 30 kw and is 27.4 miles closer to me. Its no wonder why I cant get ch 2.1 in my opinion. Maybe tvfool needs to re-consider ch 2.1 signal strength so it does fall farther down on the NM(db) chart.

[bjs81]

Originally Posted by Tower Guy

Believe only half of what you hear and less than half what you find on the Internet. Those with luck receiving VHF stations with a 91XG have such strong signals that poor antenna performance didn't matter.

Well I wasnt planning on beleiving it, figured with me living in the "extreme deep fringe aera" it was highly unlikely that I could pull in any vhf channels. But now that I have it installed and I am pulling in a station 45 miles away that is broadcast on ch 11, with the antenna pointing the oppisite direction, I will beleive it.

[GroundUrMast]

There's reason to be frustrated. You have a significant amount of time, effort and expense invested so far.

TVFool depends on accurate data from the FCC which includes transmitter power, antenna height above ground, antenna gain and antenna directional pattern. The algorithm used by TVFool also depends on terrain data from a third party source. If all the data is valid, the prediction still represents an estimate, because there are countless other variables that can influence real world reception conditions. Variable factors due to weather/atmospheric conditions, foliage, structures, real antenna system performance at a given frequency, etc. will play a roll in real world results, but are impossible to factor into a prediction.

When I look at a report entry that indicates a single digit NM value, a 2-edge path profile, a co-channel interference warning and the presence of an adjacent channel that's 15 dB stronger, I see plenty of reason to expect difficulty receiving that signal. If I decide that reliable reception of that signal is a must, I have to anticipate that I may need to go to 'extraordinary lengths' to achieve the desired result.

Though it may be obvious, it's worth pointing out to other readers of this thread, that just because a signal is at the top of a given report table, does not indicate that it is easy to receive... Occasionally we see reports with a list of signals, none of which are of sufficient strength or quality to expect reliable reception. In your specific case, all signals shown on your report are challenging. You're doing remarkably well with many signals that others with just a few trees nearby would find impossible to receive reliably.

As I recall, the 91XG and an Antennacraft Y10713 among the antennas suggestions made in your first thread. The Y10713 looks like it will soon disappear from the market place due to the Radio Shack bankruptcy. If I was in your area, I'd actually consider buying one or even two Y10713's. A pair of Y10713's correctly ganged could offer a measurable improvement in gain over the CA8100 at real CH-12. The question of, 'would it be worth it?' is, of course, one that each person would have to answer for themselves.