OTA Digital TV reception question

[ceemike]

I need some help understanding OTA DTV reception. One of the channels I receive comes & goes depending on the weather or time of day. I'm in the Orlando, FL area for the winter (ZIP 33896) & the local NBC station, WESH 2, comes in fine during the day but not at night. WESH broadcasts on the VHF channel 11, 201 MHz. The signal strength is between 50 & 60% but the picture quality can vary between 40% during the day to 0 at night. My antenna is the Winegard Sensar with the Wingman. I have the BOMB with the antenna amplifier. I get many other stations, mostly all on the UHF band, some from as far away as Tampa.

[BFlinn181]

It's the nature of digital signals in the most part. In the 'olden days' weak signals on analog channels might come in as a snowy picture. Digital signals are either all there or nothing. The digital signal can be blocked by a tree, wind, or a person walking in between you and the antenna. Digital doesn't travel as far as analog signals, but they remain clear and sharp as far as they go.

[bluepill]

Basic question: Have you rotated the antenna to see if there is a change for better or worse?

[ceemike]

Originally Posted by bluepill

Basic question: Have you rotated the antenna to see if there is a change for better or worse?

Yes, I rotate the antenna until I get the best Signal Strength reading. On most of the channels that also gives me the best Signal Quality reading. With the channel in question, the Signal Quality reading goes to 0 in the evening.

[Jim A]

I am not sure if it is likely, but I had a situation in Phoenix where I actually had a couple of stations I lost because the signal was too strong. I have the SensarPro unit, and if I raised the amplification to pull in a weak station, I lost a couple of stations that had been coming in fine. When I turned it back down, I regained the stations I lost, but lost the weak ones. If you are in town and close to the towers, it is possible.

Easy to check for this. The BOMB amplification is not adjustable. Turn the antenna slightly off line to weaken the signal and see if it comes in. You only have a problem with the VHF station, not any of the UHF stations, and the Sensar is a good VHF antenna. (Good at UHF too with the Wingman.)

A few people on here have reported LED lights interfering with OTA reception. I have never seen it, and I have plenty of LED lights. But if you have them, try turning them off. (I would assume they are off during the daytime.) I will be shocked it this makes any difference, but it only takes a few seconds to eliminate it as a possibility.

Then I would start looking at coax connections. I am always suspicious of connections when a problem is intermittent.

[Davdeb1]

I would run the cable from the antenna directly to the TV and try to auto tune it that way, just to see what happens.

[wa8yxm]

They teach college level courses in radio propagation... So do not expect a full answer here.

Many stations operate at two power levels, day and night, they may be reducing power at night.

Sunlight can help or hinder a station's range.

Weather at those frequencies can affect the range, though this is worse at UHF than at chan 11,, are you sure they are broadcasting on 11?

So can birds, Trees, and other obstructions.

[wildtoad]

Quite common with the new digital signals. Very curious in that one second you can have a very strong / good signal and the next second you get crap. Rain, trees, other objects can cause signals to be lost.

It's also confusing as to what channel is what. Right now I can get channel 4.1 ( as example ) on the right setting, but it's "sister" channel 4.2 comes in on 33.x.
Always something to learn about.

[DegoRed]

Something to check out. Look up each station you are trying to get and see what actuall band they are transmitting on. For example, in my area, 3 of stations use VHF while 2 of them use UHF.

I had tried 3 or 4 atenna's out only to meet with fustration on why I could not pull in all 5 of the OTA broacasts. Then read in a forum about the different frequencies, and tried the different frequency antennas out and bingo. So now I use 2 different antennas and join them together when I bring the signal into the house.

Not saying this is your problem or your solution, but it is certainly worth looking in to, as it was mine. FYI both of the antennas that I bought were under $40 each, so dont think you need to buy a special $100+ antenna. Also, if you call these guys Solid Signal - Signal Solutions including HDTV Antennas, DIRECTV & DISH Network satellite equipment and home entertainment supplies & accessories they are some pretty smart people, who were very helpful to me.

Good luck!

[taylorgso]

You may want to go to tvfool.com or antenna point.com (or other locator site) and key in your location. The site will tell you what stations are available in your area, the virtual channel number and the RF channel number, and the direction and distance from your zip code. This can assist in aiming your antenna.

[gemini5362]

If you want to look this up go for it but basically it is a phenomenon of RF signals bouncing off of the ionosphere. The ionosphere moves up and down depending on day or night. Where you are now is a strong signal because of bounce during the day. At night the bouncepoint has moved up and the angle has been changed because of the movement. You might be totally outside of the area that is seen at night.

IF you have good signal during the day but not at night it will not be anything at all to do with your equipment do not bother to waste time troubleshooting it.

Skywave - Wikipedia, the free encyclopedia

[wa8yxm]

If you want to study it the American Radio Relay League has lots of books on the subject of radio propagation.. After all, we ham radio operators are sending signals around the world often with less than 100 watts of fire in the wire as it were So we need to know this stuff (I have several contacts with European countries pushing less than 50 watts into a simple 100' wire)

I have sat in front of the radio and listened to a Net Control on a net that is in progress as I type this, go from solid copy S-9 (Very strong) Signal to well below the noise floor could only detect he was talking.

And he was in "4-land" (where I'm parked) only a couple states away from me.

And I've heard the other end.. What changed.. Sunset/Sunrise.

I see the same thing a station that is 90 in the day, showing 60 or less at night.

[ctpres]

What I did that helps. Cut center out of six inch compass and added a couple large plastic washers. Removed handle and pointer disk screwed to ceiling and reinstall so compass will rotate between pointer and ceiling. Typical Winegard install has antenna pointed directly at curb when raised to full extension. Take magnetic hand held compass and get heading for antenna (for me that means just shooting across rear of coach) then just rotate compass on ceiling till pointer and magnetic heading match. Using site like antennapoint.com find station angle from your location and rotate antenna so pointer is at station angle. Simple way of saying - plastic compass compensates for RV heading and antenna offset. I can tweek a weak station or change city in less than five minutes. Station scan takes longer.

[alilly]

Originally Posted by wa8yxm

They teach college level courses in radio propagation... So do not expect a full answer here.

Many stations operate at two power levels, day and night, they may be reducing power at night.

Sunlight can help or hinder a station's range.

Weather at those frequencies can affect the range, though this is worse at UHF than at chan 11,, are you sure they are broadcasting on 11?

So can birds, Trees, and other obstructions.

In regard to power reduction on tv signal power at night, tv and fm stations don't do that. It's illegal. That's an am station rule.