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Old 8-Sep-2015, 9:12 PM   #1
brin831
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Join Date: Jun 2012
Location: concord, nc
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help with reception in nc

http://www.tvfool.com/?option=com_wr...8e03f5e6791066

was thinking roof mount 4 or 8 bay hdb8x ?? want to split to 4+ tv's 50 ft to split and another 50 to 75 in house.

house is in a very heavily wooded area lots of trees around.

recommendations?

would i need a preamp if i split 4 times?
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Old 10-Sep-2015, 1:19 PM   #2
rabbit73
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I suggest an 8-bay UHF antenna like the Antennas Direct DB8E with both panels aimed at 260 degrees magnetic. You will have the best luck staying with one direction. I don't have any experience with the Solid Signal Xtreme Signal HDB8X, but the price looks good.
http://www.solidsignal.com/pview.asp?p=hdb8x

Quote:
house is in a very heavily wooded area lots of trees around.
Bad news; trees block signals.

First try the antenna with a 4-way splitter.

If that doesn't work, replace the splitter with a Channel Master 3414.

If that doesn't work try a Channel Master 7778 preamp at the antenna and a 4-way splitter down below.

If that doesn't work try a Channel Master 7778 at the antenna and a 3414 down below.

If that doesn't work cut some trees.

If that doesn't work put up a tower.
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Last edited by rabbit73; 10-Sep-2015 at 1:58 PM.
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Old 10-Sep-2015, 1:34 PM   #3
rickbb
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Problem 1, bow ties are highly directional and do best when aimed directly at the transmitter tower(s).

Your 2 main directions to receive signals are almost 90 degrees apart, which means you will need to split your aiming directions to try and pick up stations from both directions. A 4 bay will do better in that regard as their beam width is a bit wider than an 8 bay.

Problem 2, is the trees, they will block a significant amount of signal. Having said that if you can get your antenna up high enough you may find a sweet spot where the signal is getting over the trees. Sometimes a few feet one way or the other can find a spot where the signal is getting though. (Look up multi-path interference.)

Problem 3, 4 TV's. You have some close strong signals and some not so strong, also affected by trees. You will be cutting the signal to each TV to 1/4 of what the antenna picks up and you have long cable runs which drops even more signal.

That indicates that a pre-amp might be needed, BUT, with close strong stations you can easily overload your tuners with it causing even more loss of stations.

I think if you start with a 4 bay, mounted as high as you can get it, run to one TV with the shortest run, no splitter and see what you can get. Aim it about 260 degrees magnetic which is 20 degrees to the south. This should still pick up your stations from 285 but give you a chance at the really strong channels at 185 degrees mag.
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Old 11-Sep-2015, 12:30 PM   #4
ADTech
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Posts: 2,940
Rick,

The -3 db beamwidth of a 4-bay antenna generally is between 40-70, depending on frequency. A spread of 90 is unlikely to be covered satisfactorily by a 4-bay. Our DB4e, for example is down to around -5 to +5 dBi gain at 90, again depending on frequency. You can expect almost any 4-bay antenna to behave similarly.

For stations at or near 90 to each other, you're usually better off with two identical antennas combined (splitter & identical coax leads) and mounted at 90 relative to each other ala our DB8e. Your results will still "vary significantly", but that arrangement offers the best compromise available. After that, a rotor is recommended or someone can try one of the "omni-directional" antennas that claim to receive from all directions. The combining loss of the two antennas is much less than the reduction in gain from being so far off boresite.
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Last edited by ADTech; 11-Sep-2015 at 12:37 PM.
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Old 11-Sep-2015, 1:23 PM   #5
rickbb
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Yes I understand the null zone, but my comment was based on my situation. I have a similar 90 degree apart transmitter issue and was able to tune in both directions by aiming my 4 bay about 20 degrees away from one tower direction.

The 90 degree off tower cluster is much closer and more LOS to me so being further out of the main beam path was somewhat compensated by the stronger signal arriving at my antenna. At least enough to allow me to tune in those channels. (Well other than the tree problem, but that's another issue.)

The main direction is further away and 2edge, but even with my antenna aimed 20 degrees away the signal quality is still quite good. I only have very occasional weather related problems with the one VHF-HI channel from that direction.

PS. My 4 bay is a DIY based on Mclapp's 10 x 9.5, no reflector.

Last edited by rickbb; 11-Sep-2015 at 1:25 PM. Reason: add antenna info
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