Need some advice re antennae & unusual case of poor reception - AVS Forum
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post #1 of 20 Old 11-04-2009, 09:20 AM - Thread Starter
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I'm hoping someone can give me some definitive information on whether I need a new antenna. (I'm a dinosaur and I don't need any kind of subscription TV.) I don't think I need a new one, but I'm no engineer.

I'm currently using the same old UHF/VHF antenna I've had for many years, and a converter box. Most of the time, it works fine, and I have perfect reception.

Last nite, however, I was getting some interruptions, or pauses, on one of the major channels. This was quite unusual; usually it comes in perfectly. Out of curiosity, I spent some time on each of the 20 channels I get to see if any of them had any difficulties. Only 2 did--the one I was watching, and another one. A check with Antennaweb.org shows that every channel I get is on the same compass heading. And last nite the weather was clear.


I called a broadcast engineer at the station to ask if he could make any guesses as to why I had problems with his signal, and his reply was that I needed a new antenna, since his signal, like all DTV signals, was broadcast on UHF. But this answer does not address the question of (a) why was the signal from his station not so good, last nite; and (b) if I really do need a new antenna, how come it works so well most of the time on almost all the stations? (My conclusion is that this fellow does not know what he is talking about and probably does not have technical training as an engineer.)

Anyone have any suggestions or ideas about this?
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post #2 of 20 Old 11-04-2009, 09:39 AM
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Go to TV Fool, enter your location, and post the link here.

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post #3 of 20 Old 11-04-2009, 09:41 AM
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I'd not jump to any conclusions or drastic measures. Wait and see if the "problems" become consistent.

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post #4 of 20 Old 11-05-2009, 07:19 AM
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If it keeps happening, see if you can correlate it to some other phenomenon -- a neighbor with a leaf blower, an arcing power transformer, a blinking street light, that sort of thing.
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post #5 of 20 Old 11-06-2009, 09:32 AM
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Reception can be very weather-dependent. Also some of the worst reception can occur in clear weather, especially if it is windy.
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post #6 of 20 Old 11-06-2009, 04:11 PM
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A link to your TVFool results would help.
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post #7 of 20 Old 11-18-2009, 03:07 PM
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I'm glad someone asked! I seem to have a similar issue lately. Here is tvfool link from near my neighbhorhood:
http://www.tvfool.com/?option=com_wr...bc27811487889e

About a couple weeks ago, I started having issues on Ch 5(uhf) and especially Chs 7,9 (VHF). I figured prob was because leaves had come down and likely changed some multipath issue and my antenna setup was with an old builder grade antenna that had a broken dipole and was sitting on a box in the attic.

Well I changed to an RCA ANT751 (easy to pick up at walmart) and mounted it in the attic. With that I still seem to have trouble getting a good signal across the spectrum. At one point, 7,9 would bounce between strong and 0 signal. AFter more minor pointing, I seem to get strong signals on 7,9 but 5 is now borderline (Ch 5 is 1 degree off of Ch 7,9). I'm even getting B'more stations 11,13 (borderline, but watchable at times). However, I'm not confident 7,9 will stay strong based on my observations so far.
As I mentioned, being an attic, there are boxes being stored up there to the front left of the antenna about 10'ft away, any chance they could be interfering with the signal?

I'll also add, only feeding 1 tv (DTVPAL DVR), no splitters or amplifiers, and prob about 25' of coax. (Prob put n by the builder).

I'll check it out again tonight to see how it is doing.
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post #8 of 20 Old 11-18-2009, 06:15 PM
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Quote:
Originally Posted by ss_sea_ya View Post

About a couple weeks ago, I started having issues on Ch 5(uhf) and especially Chs 7,9 (VHF).

Well I changed to an RCA ANT751 (easy to pick up at walmart) and mounted it in the attic.

From the location that you posted, the Baltimore stations are too weak to expect perfect reception with an attic mounted antenna.
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post #9 of 20 Old 11-18-2009, 09:13 PM
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They (Ch 11 & 13) actually seem to come in better than ch 5. I do seem have the antenna adjusted to maximize my reception on 7 and 9. But I'm not really concerned about them, really just trying to get 5,7,9 to come in consistently, but for some reason, ch 5 seems to get worse as 7,9 reception improved. 7/9 where really really finiky.

I may attempt some more fine tuning (I already spend a hour or so tweaking back and forth), but will wait until weekend, cause I don't want to screw the channels up Thurs and Fri recordings. Not recording anything on 5 'til monday, so I can live with it for now.
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post #10 of 20 Old 11-19-2009, 06:40 AM
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Also what this engineer told you is not true...

Quote:


I needed a new antenna, since his signal, like all DTV signals, was broadcast on UHF

All DTV signals are not UHF and almost every market has at least one channel being broadcast on VHF. The antenna you are using is most likely a combo UHF/VHF antenna or you would not have been watching his channel in the first place.

We would first recommend you check your connections, cables, etc. for corrosion or just loose or bad wiring. 9 times out of 10 when we hear the story of a working antenna that starts losing some channels for no reason... that is the reason.

Andy Crowner
Winegard Company

For more information including Product Manuals, Engineering Specifications and questions answered by Winegard technicians please visit www.winegard.com.
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post #11 of 20 Old 11-21-2009, 02:05 PM
 
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Was the trouble station an ABC flagship or affiliate?
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post #12 of 20 Old 11-23-2009, 03:23 PM
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I did some more fine tuning on my antenna. I also moved some boxes that out of the way that may have been in the line of sight (although according to TVfool they really aren't).

I still seem to have issues with Ch 5 though. What is strange is ch 20 comes in much stronger than Ch 5, even though Ch 5 transmits at twice the power from the same location.
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post #13 of 20 Old 12-08-2009, 03:29 PM
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Should I expect much difference if I move the antenna outside? (Probably will be about 3' lower elevation).
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post #14 of 20 Old 12-08-2009, 03:52 PM
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Impossible to predict. But outdoor nearly always works better than indoor or attic. Typically, an attic install may attenuate the signal by ~50%. Sometimes more - sometimes less.

Since you've got some hills blocking your signals, anything you can do to improve the signal quality may help.
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post #15 of 20 Old 12-09-2009, 07:46 AM
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I really just need about a 10% increase in signal, the stations are just borderline. The antenna is pointing pretty much thru the slope of the roof (i.e. not directly at the side), so mostly just wood and single in the way. So I'm not expecting a hugh increase. May have to go with a larger antenna.
Yea, I agree, those hills are really screwing with the signal. Hopefully I can get out this weekend and try it. I'll test with a quick mount on the deck before moving it up to the the roof.
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post #16 of 20 Old 12-11-2009, 03:16 PM
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I would look into getting a bigger antenna. I have a DB8 and a H8200U mounted in my attic and if they are pointed in the right way, I can get channels in the 16 dB range.

http://www.tvfool.com/?option=com_wr...7d520dad48e4da

I can get channel 14 and above now. (and that is without an amplifier, in an attic, and with a short 12' cable run).

You may not need the same antenna, but I would look into the biggest ones that Home Depot has, or find a good one on-line.

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post #17 of 20 Old 12-12-2009, 02:43 PM
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ss_sea_ya:

I have a similar situation with channels 11 and 13 (not the Baltimore ones, though) that may be of some assistance to you. My channels 11 and 13 are 65 miles away, and are at 6.7 and 4.6 dB NM, respectively. Your TVFool report shows your channels 11 and 13 at 6.3 and 4.3 dB NM, respectively, very similar to mine. My tv requires a signal strength of 35 or better on my tv's signal meter in order to reliably lock a signal.

I have a Winegard YA-1713 VHF-high antenna in my attic, which is a very good VHF-high antenna (9-10 dB gain). In the attic, I can only occasionally lock channels 11 and 13 late at night (meaning that the signal only creeps over 35 at that time). I recently temporarily tested my YA-1713 outside at chimney height (maybe 20 feet above ground level) and channels 11 and 13 locked in fine at a 64 signal strength for both stations. At least in my area, I would roughly estimate that the YA-1713 would reliably receive VHF-high stations (channels 7-13) up to about 50 miles from inside my attic and maybe 75-85 miles outside at chimney height.

Your RCA ANT751 isn't going to provide that much gain, so if it is getting your Baltimore channels 11 and 13 marginally from inside your attic, perhaps a YA-1713 would get them just fine from your attic. If you pointed a YA-1713 either directly toward Baltimore, or maybe in-between the Baltimore and Washington directions (for 7 and 9), maybe that would work just fine for you. You do lose maybe 25-35% of your signal from the attic, but that can be compensated for somewhat by bigger antenna(s).

Can you still return your RCA ANT751 (maybe you're still within 30 days of purchase)? The YA-1713 isn't too expensive, and you would join it with a suitable not-too-expensive UHF-only antenna with a UVSJ to get a much better overall solution, perhaps from your attic. Maybe this combination would be a better (and not-too-expensive) solution:

http://www.solidsignal.com/pview.asp...-(YA1713)&c=TV Antennas&sku=615798304867
http://www.solidsignal.com/pview.asp...-(HD8800)&c=TV Antennas&sku=615798398118
http://www.solidsignal.com/pview.asp...UVSJ)&c=Signal Combiners&sku=UVSJ

Of course, these are much bigger antennas, so your attic would have to be able to handle the size. I have mine hung separately 10 feet apart from each other along the very highest point of my attic (just about touching the rafters) on 4-foot pieces of 1" PVC pipe ($2), each attached to a rafter by a single long screw going through a drilled hole an inch from the end of each pipe. In the spring, I'll have to add an outside antenna for my distant stations, but maybe yours will come in from the attic.

Hope this is helpful...
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post #18 of 20 Old 12-12-2009, 04:58 PM
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How in hell can anyone 13 miles just west of south of the Wisconsin Ave towers be crippled by two-edge transmission paths? Did you dig your own trench to live in?

You need to first, pull up a new TVFool table using your exact coordinates and your exact antenna height, and then you should also draw lines on a map from your exact location to each tower and then drive around and see if they go through any Charles Smith buildings. If they do, all bets are off. Some years ago, I had to get channel 50 reception for the Holiday Inn and for a sportsbar in Old Town, Alexandria, but could only do so by playing bounces off buildings to their due west.
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post #19 of 20 Old 12-12-2009, 05:58 PM
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Have you ever driven the GW Parkway and noticed how high you get? Isn't that South and West of the transmitters?
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post #20 of 20 Old 12-19-2009, 02:25 PM
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Last weekend, I did try a quick install on the edge of the roof with no improvements. Didn't have time to make more that one mount and various angle adjustments, non seem to help.
So its back in the attic. Used a compass and seem to have better reception, but 5 still an issue. prob just a null point, so until i'll may have to live with it. Might go with a higher gain antenna at some point, but for now, itlll have to do.
With the snow, everything is trying to come it, so let it so let is snow, let it snow. (even the B'more stations!)

I do appreciate the interest and tips. Will likely have to followup sometime mid-winter.
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