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Old 27-Oct-2014, 12:21 AM   #1
tradewinds
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Assistance on Antenna selection

Here is my TVFool:
http://www.tvfool.com/?option=com_wr...d24343b35abb6b


I am trying to get some guidance on what setup I would need to get the following channels:

FOX:
WTVT-DT 205 60miles (Tampa)
WOGX-DT 329 60miles (Ocala)

CBS:
WTSP 206 60miles (Tampa)
WGFL-DT 327 83miles (Gainsville)

I already have an 91XG and Y5-7-13 to pick up my Orlando locals pointing to Bithlo.

Thanks for your assistance.

Last edited by tradewinds; 27-Oct-2014 at 12:26 AM.
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Old 27-Oct-2014, 9:08 AM   #2
timgr
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WTSP 10, WTVT 12 and WGFL 28 are -17, -18 and -19 dB NM. I'd put those in the "impossible" category at the current antenna height.

It should be possible to pick up WOGX 31 at -0.3 dB NM if you point your 91XG at it. But you'll likely have to point right at it and a preamp at the antenna should help. But it's very weak at that height.

Can you go a lot higher? Run your report again with a better antenna height.
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Old 27-Oct-2014, 12:26 PM   #3
tradewinds
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Thanks time, here it is at 40 AGL.
And at 50 AGL.

Last edited by tradewinds; 27-Oct-2014 at 12:28 PM.
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Old 27-Oct-2014, 12:56 PM   #4
ADTech
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You must be in a terrain "hole" to have numbers that low at those modest distances in central Florida.
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Old 27-Oct-2014, 1:09 PM   #5
timgr
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Ok, 10 & 12 are VHF high, and the most sensitive readily available antenna for that band is a Antennacraft Y10713. It has about a 9 dB gain, so add that to the noise margin of the channel at each height, and then subtract some for the tuner, preamp and cable losses, say 6 dB? Those stations may become reachable at 50 ft, at 6.9 and 4.0 resp. Your Y5713 is about 6dB IIRC, which is half the power gain of a Y10713.

Ch 28 doesn't change much with 50' height, staying impossibly weak at -18 dB NM (still tropospheric, ie badly obstructed from your location).

There's no guarantee that 50' and a Y10713 would bring in those two stations, but I'd try it if I could get up that high. They are close enough that you'd probably get both of them.

NB I'm an engineer and have been playing along here for a while, but not in the industry... hopefully one of the industry people will correct me if needed.
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Old 27-Oct-2014, 1:22 PM   #6
tradewinds
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Quote:
Originally Posted by ADTech View Post
You must be in a terrain "hole" to have numbers that low at those modest distances in central Florida.
Yes, indeed I'm in a little ditch here but I agree with those distances I was not expecting to be in the "impossible" category given newer technology that may be able to assist.

Quote:
Originally Posted by timgr View Post
Ok, 10 & 12 are VHF high, and the most sensitive readily available antenna for that band is a Antennacraft Y10713. It has about a 9 dB gain, so add that to the noise margin of the channel at each height, and then subtract some for the tuner, preamp and cable losses, say 6 dB? Those stations may become reachable at 50 ft, at 6.9 and 4.0 resp. Your Y5713 is about 6dB IIRC, which is half the power gain of a Y10713.

Ch 28 doesn't change much with 50' height, staying impossibly weak at -18 dB NM (still tropospheric, ie badly obstructed from your location).

There's no guarantee that 50' and a Y10713 would bring in those two stations, but I'd try it if I could get up that high. They are close enough that you'd probably get both of them.

NB I'm an engineer and have been playing along here for a while, but not in the industry... hopefully one of the industry people will correct me if needed.
Yes, getting to 50ft is definitely going to be something probably not worth doing even with a gauratee. The peek of my roof is about 30 AGL where I can probably get an antenna into the attic around that height.
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Old 27-Oct-2014, 1:27 PM   #7
timgr
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You mean around 25'?

The attic and the roof are nowhere near equivalent locations, even at the same height. Everything we've been talking about is in the free air. Attics are a whole other story.

You can get to 50' from a 30' roof peak. Buy a 20' extendable mast, and mount it to the peak with a mount like this - http://www.antennapartsoutlet.com/Pa...DGEMOUNTS.html Run guy wires down to the roof edges.
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Old 27-Oct-2014, 2:05 PM   #8
tradewinds
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You mean around 25'?

The attic and the roof are nowhere near equivalent locations, even at the same height. Everything we've been talking about is in the free air. Attics are a whole other story.

You can get to 50' from a 30' roof peak. Buy a 20' extendable mast, and mount it to the peak with a mount like this - http://www.antennapartsoutlet.com/Pa...DGEMOUNTS.html Run guy wires down to the roof edges.
Yes, you're right. About 25-26 ft. But I agree, free air is what I was also thinking as my current antenna is at about 23 feet on one of those dish J-mount at the edge of the roof.

The WAF of a 20ft on the top with guy wire is probably going to be a challenge very difficult to win. If that is the only way, then at least I now know what is realistic to achieve.
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Old 27-Oct-2014, 2:22 PM   #9
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Upgrade the Y5 to the Y10, add a low-noise, medium gain pre-amp and a capable rotor, and get as much elevation so as to clear any local obstacles (buildings, trees, etc), and give it a shot. That's about the best that you can do.

You can expect to get most of the stations some of the time, some of the stations most of the time, and, perhaps, a few all of the time.
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Old 27-Oct-2014, 2:48 PM   #10
tradewinds
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Quote:
Originally Posted by ADTech View Post
Upgrade the Y5 to the Y10, add a low-noise, medium gain pre-amp and a capable rotor, and get as much elevation so as to clear any local obstacles (buildings, trees, etc), and give it a shot. That's about the best that you can do.

You can expect to get most of the stations some of the time, some of the stations most of the time, and, perhaps, a few all of the time.
Well, i'll like to keep my existing 91XG and Y5 fixed where they are pointing to my market's locals (Orlando) to keep the DVR happy.

I am just trying to get the other markets (Tampa and Ocala/Gainsville) for NFL games on CBS and FOX as they are sometimes different games.

Is there a good rotor that is available? I saw there was a Disquec one available but not longer manufactured but all the others seems cheaply made.

Since only the the Tampa is VHF, I can try a fixed Y10 to that direction. For the Ocala/Gainsville, I'm not sure if I even have a chance and what antenna would work for those UHF with those distance and NM.
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Old 28-Oct-2014, 12:49 PM   #11
timgr
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The signal for the two Tampa stations increases nicely with height, so there's a good chance to get both of them with the added height and a fixed Y10713. You can start out with a 10.5' chain link top rail - cheap at the home center - for a mast on your roof peak - that will get you to 40' and see how it goes.

Both Ocala and Gainesville do not change much with extra height ... not promising. I would forget trying to get the Gainesville station - it's just too weak. Finding ca 24 dB of antenna gain just isn't practical without maybe a big antenna array or something like the fabled rhombic http://en.wikipedia.org/wiki/Rhombic_antenna ... you think the 20' mast has a low WAF...

Easy to do a test and aim your existing 91XG at Ocala and see if it comes in. If it does, put a second 91XG on the same mast as the Y10713 and direct the combined preamplified and UHF-VHF mixed downlead to an A/B switch or a stand-alone tuner like the Homerun HD. No rotator needed, and optimistically you'd get three of your four target stations.
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Old 28-Oct-2014, 2:12 PM   #12
tradewinds
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Thanks Tim, so the net of it (and that is the assurance I was needing) is the two antennas needed are a Y10713 and another 91XG. This makes things a lot easier to get going.

I assume I can combine the UHF from both 91XG into a reverse splitter and VHF from my Y5713 and the Y10713 into another reverse splitter, then take those two outputs and put them into the respective preamp UHF and VHF inputs of my CM 7777 preamp combiner?
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Old 28-Oct-2014, 2:52 PM   #13
timgr
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I would not combine the antennas that way. I would keep the (UHF-VHF combined) downleads completely separate until I reached an A/B switch or some other isolating device. Combining antennas on the same band is a whole other technical issue, which I would avoid. You can combine the VHF and UHF signals on the same cable, since they are different frequencies and don't interfere. Your tuner filters out the frequencies that it wants and rejects the rest. A second tuner or an A/B switch would give you the kind of isolation you'll need to have multiple sources (antennae) on the same frequency.

http://www.solidsignal.com/pview.asp?p=tv-0151

http://www.silicondust.com/products/...dhomerun-dual/

I would use a new mast mounted preamp to combine the new antennas. The RCA preamp http://www.amazon.com/RCA-TVPRAMP1R-.../dp/B003P92D9Y is recommended often - look at old posts for discussion. I have the Antennacraft 10G221 http://www.antennacraft.net/Antennas...mplifiers.html (not in service yet) since it was recommended to me by the experts here. Or you could move the CM7777 to the new mast and use the RCA on your existing installation.

Your other option is a UVSJ http://www.solidsignal.com/pview.asp?p=uvsj but it has a 0.5 dB loss.

Realize that these masts need to be far enough apart so that the same-frequency antennas are isolated electrically. I would guess that's a minimum of about 6', though 12' would be better.

http://www.kyes.com/antenna/stacking.html

Last edited by timgr; 28-Oct-2014 at 2:57 PM.
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Old 28-Oct-2014, 3:03 PM   #14
tradewinds
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thank you. Glad I asked as my assumption was faulty.
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