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Old 9-Aug-2012, 1:47 AM   #1
wirenut
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help with weak signal

Radar-All.pngI have a rca 3036wr antenna mounted on my roof about 35 ft from ground, i have aska am125 ,25db distribution amp installed going to 3 way splitter to 3 tvs .I have 4/5 channels that are hit or miss . Any ideas how to improve my setup or something i have wrong. open to any ideas ,just hate to be watching something and lose the channel..lol thanks in advance for your help

Last edited by wirenut; 9-Aug-2012 at 2:10 AM. Reason: add tvfool report
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Old 9-Aug-2012, 2:45 AM   #2
thom
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Wow, you must have serious terrain challenges.

The noise margin (NM) says you need gain, lots of gain, at the antenna. That's got to be positive before it even hits the preamp.
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Old 9-Aug-2012, 5:03 AM   #3
teleview
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Tv Reception.

So much incorrect and misinformation out there.

And people insist on piling on more and more incorrect information.

The receivable Tv stations do not have to have Positive NM (dB) numbers before ' it hits ' the amplifier.

Many Digital Tv tuners are capable of receiving NM (dB) numbers at minus -5 and even minus -10 NM (dB).

_________________________________

For a more accurate evaluation of your reception situation , please make a live and active tvfool report like as an example you will see at the other question askers posts.

The picture of the report that you provided is dead , can not do any thing with it.
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Old 9-Aug-2012, 5:47 AM   #4
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TV Fool disagrees

"Although it is theoretically possible to get a channel at 0 dB NM, this would probably result in a very unpleasant viewing experience because random signal fluctuations will probably cause the signal to dip below the threshold quite often and result in drop-outs, macro-blocking, or other artifacts. "

http://www.tvfool.com/?option=com_co...ask=view&id=57
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Old 9-Aug-2012, 6:08 AM   #5
teleview
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Tv Reception.

I have installed real and actual antennas and installations with the reception reliable at a starting signal strength of -10 NM (dB).

The result of field tests is.

The FCC Federal Communications Commission and Technical Industry standard reference is a , simple dipole , at 30 feet antenna height and 0 NM (dB) with no obstructions between the transmitting antenna and receiving antenna.

It is true that a NM (dB) of plus +10 or more is better.

And it is true that when I recommend reception , I say that the signal strengths are Very Weak , making the point that a Large antenna and etc. is what it will take to get reliable reception.

Last edited by teleview; 9-Aug-2012 at 3:49 PM.
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Old 9-Aug-2012, 3:38 PM   #6
GroundUrMast
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In this case it appears reasonable to expect reception of the first three signals.

A Winegard HD7084P equipped with an Antennas Direct CPA-19 would be my choice of equipment if starting from scratch.

I would like to understand the terrain better. Because an image of the TV Fool report wast posted rather than an active link, it's not possible to click on the station call sign to see the path profile.

Also, can the antenna be mounted higher? Are there trees or buildings in the way of the antenna?


As an aside;

While there are examples of successful reception of signals predicted to be 10 dB lower than the minimum required noise margin, such examples are the exception rather than the norm. I submit that the prediction may have been lower than the actual conditions and I'm confident that the antenna used was not a 'standard dipole' but rather a high gain directional. The statement, "Many Digital Tv tuners are capable of receiving NM (dB) numbers at minus -5 and even minus -10 NM (dB)." demonstrates a lack of understanding of Johnson-Nyquist noise, http://en.wikipedia.org/wiki/Johnson...3Nyquist_noise and Nyquist Theorem http://en.wikipedia.org/wiki/Nyquist...mpling_theorem http://en.wikipedia.org/wiki/Nyquist_rate. In fact, typical 'good' tuners need a signal with a Net-NM of +6 to +9 dB because the active electronics in the tuner generate noise in excess of the passive 75Ω antenna system impedance. http://en.allexperts.com/q/Wireless-...rmal-noise.htm

I agree that if the actual NM is negative at the input to the preamp, there is no reason to expect it to magically become positive in the preamp or hardware that follows. Antenna gain is the only gain that can improve signal NM. The gain of the preamp comes at the cost of additional noise. http://forum.tvfool.com/showthread.php?t=109

I would welcome the opportunity to read references that support the claim, "The FCC Federal Communications Commission and Technical Industry standard reference is a , simple dipole , at 30 feet antenna height and 0 NM (dB) with no obstructions between the transmitting antenna and receiving antenna." This claim contradicts the concept of the 'TV Service Contour', http://transition.fcc.gov/Bureaus/MB...ta/readme.html and the FCC "Tests of ATSC 8-VSB Reception Performance of Consumer Digital Television Receivers", http://www.google.com/url?sa=t&rct=j...nLwagBHwiOmsTw

Last edited by GroundUrMast; 14-Aug-2012 at 11:50 PM. Reason: An aside...
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Old 9-Aug-2012, 9:56 PM   #7
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Thanks to you all for the advice, Think i will try the winegard antenna and pre amp and try and go higher and see how that helps ,again thanks
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Old 9-Aug-2012, 10:03 PM   #8
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Let us know how you do. Again, if you get a chance, an active link to your TV Fool Report would be a source of more helpful information.

Cheers
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Old 14-Aug-2012, 11:35 PM   #9
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http://www.tvfool.com/?option=com_wr...99007eb4298925
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Old 15-Aug-2012, 12:03 AM   #10
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Thanks for the active link. When you click on a station call sign, you get a graphical display of the path profile... The transmitter is shown on the left, terrain cross section in the middle and your receiving location on the far right. Looking at WEMT as an example, you see the tall mountain ridge that blocks your line of sight toward the transmitter.

The HD7084P and preamp is still the best suggestion I've got. Higher is better no doubt.
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Old 15-Aug-2012, 7:45 AM   #11
teleview
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Tv Reception.

Here is a way to receive more Tv channels.

FTA= Free To Air Satellite Tv.

Tv channels are free to receive , with a small dish and receiver.

Here is a good place to start , http://www.ftalist.com

Last edited by teleview; 22-Aug-2012 at 4:52 AM.
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Old 21-Aug-2012, 12:42 AM   #12
wirenut
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Ok guys i got the new winegard antenna and preamp installed , i went up about 10 ft. highter so now i am about 40 ft .from ground .All i can say is thanks , the difference is amazing not only did the new setup fix my weak channels fading in and out but i also picked up 3 new channels I now get a total of 16 channels. I now get 2 channels that are 120miles away .I waited 3 days to post this just to see how it worked so far no channel fade, All i can say is thank you very much for all your help and advice, Free tv is great lol again thanks.
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Old 21-Aug-2012, 3:21 AM   #13
teleview
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Tv Reception.

I am gethering information on Tv stations that are received.

Please list the Tv stations that you are receiving.

Here are 2 examples of how to list.

WCYB , NBC.

WEMT , FOX.

Did you install the HD7084P antenna??

If not , what antenna did you install??

Did you install the CPA-19 preamp??

If not , what preamp did you install??

How many Tv's are connected??

Last edited by teleview; 21-Aug-2012 at 3:27 AM.
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Old 22-Aug-2012, 1:12 AM   #14
wirenut
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I installed the winegard HD7084p antenna
a windgard chromstar 2000 preamp
ASKA 125 distripution amp
40 from ground
i now get
wcyb =nbc 5.1
cw4=5.2
lw=5.3
wbir hd=nbc 10.1
wbir wx=nbc 10.2
wjhl=cbs 11.1
wjhl hd=cbs 11.2
metv 11.3
wemt=fox 39.1
this tv=39.2
wsbn hd=pbs 47.1
wsbn sd=pbs 47.2
world [news] 47.3
wlfg dt=68.1
wlfg dt=68.2
I have 3 tvs hooked up

Last edited by wirenut; 22-Aug-2012 at 1:15 AM. Reason: add
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