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Old 13-Aug-2012, 8:47 PM   #1
TheFu
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What's the general philosophy re. antenna recommendations here?

Moderators Note: This thread has been split from http://forum.tvfool.com/showthread.php?t=10944 due to the following question being of a general nature.

I'm new here. Just curious why the recommendation for a fairly large and expensive antenna over some other, less expensive option? Is it purely to get the Lo-VHF stations or just a comfort thing? Can't an old dual antenna (VHF + UHF) balun merge a $5 rabbit ear and better mid-range DB4 antenna much cheaper to get the lo-VHF channels?

I guess there is a point of time vs money and $80 really isn't all that much when compared to other complexities.

I'm just trying to learn here.

Last edited by GroundUrMast; 13-Aug-2012 at 10:00 PM. Reason: Split thread, added link to originating thread.
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Old 13-Aug-2012, 9:53 PM   #2
teleview
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Tv Reception.

The VHF low band digital channels 2 thru 6 are more negative effected by natural earth electric noise and human made electric and electronic noise/signals.

Having a antenna in the attic reduces signal strength and like the inside of a house , attics have human made electric and electronic noise.

It is best to have a antenna that has the long metal receiving elements for receiving channels 2 thru 6 to receive more of the desired Tv channels to over come electric and electronic noise.

______________________

The popular buzz words are , Pull In , Tv signals.

Tv antennas Do Not in any way shape or form "pull in" Tv signals.

Tv antennas Receive Tv signals that arrive at the metal reception elements.

The more metal reception elements and the more lengths of the the metal reception elements that resonate with the frequencies/Tv channels the better the reception will be.

The metal reception elements for Tv channels 2 thru 6 are long metal reception elements.

________________________

Combining tv antennas as you are suggesting with baluns and reversed splitters will produce negative results because of antenna cross talk and loss of reception strength because the strength of signal of one antenna is transfered to the other antenna and the antennas will be out of phase and the result is more signal loss.

There are combiners that have tuned circuits that combine UHF and VHF , UVSJ = UHF/VHF/Separator/Joiner.


And VHF low band 2 thru 6 and VHF high band 7 thru 13 , HLSJ = High/Low/Separator/Joiner.

_________________________________

For this question askers reception situation , there is no requirement to jump through hoop after hoop , install one antenna and be done with it.

I have been doing antennas for a very long time , I do my best to recommend reception with the least amount of hoop jumping.

Last edited by teleview; 13-Aug-2012 at 10:22 PM.
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Old 13-Aug-2012, 10:22 PM   #3
GroundUrMast
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1) Though some members have an interest in DIY antenna construction, most are interested in a reliable off the shelf solution.

2) When dealing with VHF channels 2 through 6, there are several sources of RF noise/interference that are not as much a factor for the High-VHF and UHF bands. For example, the RF noise produced by a compact florescent bulb falls mostly in LF, HF and lower VHF spectrum. Only a very low level of noise is produced at frequencies in the high VHF and UHF ranges.

The The NM (noise margin) value presented in the TV Fool report is not adjusted to account for noise other than that produced in the antenna terminal impedance. http://en.wikipedia.org/wiki/Johnson...3Nyquist_noise In the case of the UHF band, this is close to actual conditions. When dealing with VHF you'll need to consider the effect of noise in excess of the theoretical minimum.

The end result is, a higher gain antenna will be needed for reliable reception of Low-VHF signals than would be indicated by the unadjusted NM figure provided in a TV Fool report.

3) Attics are less than ideal locations for RF reception. The antenna is shielded from the desired signals to some degree while being closer to noise generating devices inside the home. So, if spec'ing an attic install it's prudent to recommend a larger, higher gain antenna. A simple dipole VHF antenna can work in some applications, but you need to consider the various factors that may call for a larger antenna.
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