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Old 2013-08-09, 11:28 PM   #1
Gschnettler
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Question Cincinnati, OH: omni-directional antenna question

I live in Cincinnati, Ohio. I would like to pick up TV stations from both Cincinnati and Dayton OH. The Cincinnati stations are to the West and the Dayton stations are to the North. Therefore, I figure that I need an omni-directional antenna. I use a Tivo and it may record from any station at any time so I can't rely on a rotor. Cincinnati is only 5 miles away and Dayton is 42 miles away.

Does anyone know anything about this antenna?

Halo VUTV Omnidirectional Outdoor VHF UHF Long Range Omni Directional TV Antenna

It looks promising and seems like it should meet my needs if the description is accurate. I'd like to know what you all think.

Thanks in advance for your advice.
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Old 2013-08-10, 08:59 AM   #2
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first of all I would read the new members welcome thread, here..
which as some answers to very common questions.

http://www.digitalhome.ca/forum/showthread.php?t=125161

After absorbing that, come back and post your tvfool report here, and someone will be able to provide more relavent advice. But chances are with one market being only 5 miles away, just aim for the distant market and you'll be all set, 99% of the time. You are not gonna want an omnidirectional antenna.

Post your tvfool, and we'll see what's really up there at your location..
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Old 2013-08-10, 10:48 AM   #3
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Gschnettler: I do not think that you can have omni directional and hi gain. This would not be be my first choice, because of cost. Please give Tvfool or Zip code to feed Tvfool.
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Old 2013-08-10, 12:55 PM   #4
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What a pack of LIES:
http://www.etsy.com/listing/15017180...l-uhf-vhf-long
No WAY a simple Loop is gonna provide 14 dBi UHF Gain....perhaps they left out the decimal: 1.4 dBi is more believable.
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Old 2013-08-10, 01:32 PM   #5
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I'm trying to figure out how that seller can get 7 dBi gain on high VHF and 12 dBi gain on UHF with what appears to be nothing more than a horizontal loop about 27 or 28" in diameter.....
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Old 2013-08-10, 03:09 PM   #6
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Gschnettler, I agree with the above comments: The performance claims of that antenna are very suspect.

If you're interested in a commercially-available antenna, I would suggest checking out the DB8e (thread discussion is here). You could use this antenna on a roof-top to point at both north and west to receive signals--without the use of a rotator.

Though, as Majortom points out, a multi-direction antenna likely won't be necessary with one direction of transmitters only 5 miles away. In which case you may be able to use a single--and much cheaper--DB4e antenna.
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Old 2013-08-10, 06:12 PM   #7
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Quote:
I'm trying to figure out how that seller can get 7 dBi gain on high VHF and 12 dBi gain on UHF with what appears to be nothing more than a horizontal loop about 27 or 28" in diameter.....
Its obvious that in his case dbi stands for the number of "dead bees inside", heh.
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Old 2013-08-10, 08:34 PM   #8
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HiVHF+UHF Circular Pancake Loop FakeOmni:

Just uploaded 4nec2 analysis results for above, assuming the following:

Loop Center-Center Diameter assumed to be about 27-in, based on info found at fol. Halo VuTV website:
http://www.etsy.com/listing/15017180...l-uhf-vhf-long

Analysis revealed that the Hi-VHF Azimuthal Response is very irregular...NOT Omni....and UHF is even worse.

Three versions were analyzed, based on whether the portion opposite from the Feedpoint is connected or there is a Gap cut into the Loop:

a) Loop NOT CUT opposite from Feedpoint. [Azimuthal Plots shown below.]

b) Loop with 5.25-in Gap CUT opposite from Feedpoint.

c) Loop with 1.0-in Gap CUT opposite from Feedpoint.





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Old 2013-08-10, 08:36 PM   #9
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Old 2013-08-10, 09:44 PM   #10
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FYI: I analyzed numerous Omni and Quasi-Omni Antennas for the FM Band here:
http://imageevent.com/holl_ands/omni
Any of these can be resized for the Hi-VHF Band (with identical performance) by reducing ALL dimensions by Factor=98/198=0.495, which is very close to making everything half size.

True OMNI antennas were found ONLY for Vertically Polarized signals (very common for FM Band, but not as common in TV Bands). For the more commonly encountered Horizontally Polarized TV signals, the Double-Hoop came the closest to Omnidirectional performance, but SWR was higher than it should be...but for strong signals might provide acceptable performance. Note some Double-Hoop versions added vertical elements to also receive Vertically Polarized signals, which improves overall TOTAL Gain (Horiz + Vert) and in some cases also improved the SWR.

And NO, don't expect Omni performance to extend into the UHF Band....they're going to provide very irregular azimuthal patterns similar to those found for the above single Circular Pancake Loop.

If you are looking for both Hi-VHF and UHF coverage OMNI coverage, consider stacking a UHF Double-Hoop above the Hi-VHF Double-Hoop (4-ft minimum stacking height recommended) and combining the signals using a VHF/UHF Combiner (aka UVSJ). For UHF Band, shrink FM Antenna size by Factor=98/584=0.168, which is about 1/6 the size. The UHF Band version should be modeled to determine more precise dimensions, using precise values for the intended Element Radius.
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Old 2013-08-10, 11:25 PM   #11
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Quote:
Three versions were analyzed, based on whether the portion opposite from the Feedpoint is connected or there is a Gap cut into the Loop:
I saw that odd feature too. If you notice, he uses white electrical tape, so I think its just for snugging up the element for a hole drilled too large in the 1/2" pvc pipe. 1/2" sch 40 pvc is 7/8" outside diameter, so I think that may be a 3/8" aluminum element.

If there were a gap cut into the loop opposite the feedpoint, I would think he would have used another tee at that location.

Even though its a very poor gain antenna, I do like his construction technique, although using grey pvc pipe would have been cheaper and would last longer outdoors.
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Old 2013-08-11, 03:17 PM   #12
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I assumed QICT (Quarter Inch Copper Tubing) because I wasn't sure about the size in the Halo VuTV and simply used what was in the original Hi-VHF Loop 4nec2 File before I exchanged X/Y/Z columns to "pancake" the antenna. Using 3/8-in Al won't change Gain by more than a couple tenths of a dB and improvement to SWR will be fairly small. And only a bit of an improvement if use 1/2-in Copper Tubing. There is no way to pretty up this pig with bigger lipstick....
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Old 2013-08-12, 03:00 PM   #13
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They probably just put a cheap 15dB preamp on it the get the claimed gain. That's pretty typical for most of these antenna shysters. That's a pig with really bad lipstick.

As for the OP's request. I would use a 4 or 8 bay bow tie pointed a Dayton, then fine tune if any Cincinnati channels are missing. Posting a TVFool.com report would help.
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Old 2013-08-13, 12:30 AM   #14
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On the Halo VuTV webpage, it explicitly states that it is NOT amplified.....

BTW: Antenna "Gain" is created by suppressing Gain in some directions, such as a narrower beamwidth (clearly NOT an Omni) or by narrowing the ELEVATION Gain Pattern, as is very common for Broadcast "Turnstile" Antenna Arrays by VERTICALLY STACKING multiple antennas and by using (typically) four Stacked Arrays, each mounted on a different side of the tower.

HOWEVER, designing a WIDEBAND Stacked Omni turns out to be much more difficult than one would think....as evidenced by the paucity of SUCCESSFUL designs posted on this forum...I have a few UNsuccessful attempts I have NOT posted. (Q: Are there ANY???)
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