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Old 30-Sep-2011, 5:06 PM   #1
rickyv101
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Help!! Antenna VS Antenna with pre-Amp?

I would like to buy a HDTV Antenna, I am confused about Antenna on the Market.

There are inexpensive small Antenna 6-8 element with pre-Amp with rotor all in one, selling for $40- $70 with 30dbi UHF high gain.

Any information on comparing this Type of Pre-amp Antenna (30dbi) with traditional Antenna (DB4, DB8, Yaki) with 10-13DBl only?

I am hoping that those small all in one antenna are that great, They are very small and much safy to put up on my roof without worry about wind.

Anyone try it?
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Old 30-Sep-2011, 8:07 PM   #2
GroundUrMast
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Please post a link to your TV Fool report.

http://forum.tvfool.com/showthread.php?t=4

It's easy to think that an amplifier can somehow magically make a small antenna more powerful... The reality is that that is not true.

Antenna gain and amplifier gain are not the same thing. To use an analogy, think of an antenna as a well and an amplifier as a pump. A well that is not drilled deep enough would be analogous to an antenna that was too small, lacked the signal gathering ability to receive enough 'clean' signal. If you put a powerful pump at the bottom of that shallow well, you can only expect to get high pressure mud at the tap.

If you post a link, we will be happy to suggest an appropriate antenna for you.
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Old 30-Sep-2011, 8:10 PM   #3
be236
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That's a great analogy, GroundUrMast. :-)
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Old 1-Oct-2011, 3:36 AM   #4
John Candle
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Tv Antennas and Reception

The junk antennas have been dealt with Many Times here at tvfool , this is only one of the many times. Many pepole that buy junk antennas end up here at tvfool , crying with big tears. http://forum.tvfool.com/showthread.php?t=1999. And many are embarrassed to admit it so they leave that part out. Go to http://saveandreplay.com and you will be told straight out that they do not deal with , junk , clone , antennas and you will not be helped with your , junk , clone , antenna. I will not help you with your , junk , clone , antenna , I will help you get a real antenna and do it the correct way here at tvfool.

Last edited by John Candle; 2-Oct-2011 at 7:51 PM.
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Old 17-Oct-2011, 12:26 AM   #5
rickyv101
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Thanks for all your replies.

I would like to explain more, Here are my list of

http://www.tvfool.com/?option=com_wr...60b5c446db19dc

remember, only Digital TV channel available now.

I did try with 15 inch vertical wire ( May be 3db gain) on roof, I get all local channel but missing all 3 of USA channel signal strength between 74dbm to 84dbm

I made a cloth hanger DB4 antenna ( May be 6-8DB gain but 300ohm matching transformer lose 4db+) and mounted it on roof and I get the same result as 15' wires, Also it is a troublesome design, using for 2 months, I am having poor connection problem (rusting, Very wet here) so I took it down.

I tested with an old indoor RCA pre-Amp Loop VHF/UHF antenna ( Indoor only not on roof), about 20db gain, I got all local plus all USA channels but not very stable.

My understand is that, I need to increase signal strength above -70dbm, to pick up those weaker USA TV signal( -74 to -84dbm, It means that I need 14db in Antenna, it is hard for Antenna only but very easy with good Antenna with pre-AMP for this type of Gain.

I would rather to have a wider horizontal beam wide antenna with more narrower vertical beam wide antenna, Like quad type of antenna design.
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Old 17-Oct-2011, 1:52 PM   #6
ADTech
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A 15" vertical wire will not have 3 dB of gain. At best, it would be unity gain (0 dBd) before matching losses at one frequency, probably around channel 10 or so. Plus, unless your channel 10 has circular or elliptical polarization, there will be additional losses due to being improperly polarized. All stations in the US use horizontally polarization unless vertical components are added to their signal.

For the US stations, you need a highly directional UHF antenna with a steep D/B ratio. Unfortunately, your proximity to your local transmitters may result if the tuners are being desensitized to the point that reliable reception of the weak, distant signals may not be possible.
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Old 17-Oct-2011, 6:35 PM   #7
rickyv101
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ADtech, Thanks for your message about polarization, By putting that 15" wires horizontal, I gain one USA channel, Anyway, It is a test antenna.

I learned many Antenna components
- TVfool signal strength map
- BareAntenna gain
- PreAmp gain
- PreAmp can overload by strong signal (need to use steep D/B ratio antenna to block strong local signal)
- Min. TV signal strength, -70dbm, some TV can pick up -80dbm.
- Antenna durability ( I don't need a very durable antenna)
- Wind resistance ( No strong wind here)
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