Welcome,   •  Sign In  •  Register  •  Help

DTV reception problem question

Started by algopher • Aug 28, 2007 • 29 posts
Read-only archive
#1
I've had this set, Westinghouse SK32H240S, for about 2 months and am very happy with pictures and operation except for reception of Chnl 15 over the air. I have an outside antenna which if I remember correctly is a Radio Shack VU-75 with stations about 45 miles away. All digital and HD come in great except for this Channel 15.1 & 15.2 which are either not on at all or have massive pixelation. Channel 44.1 is usually rock solid, and is on the same tower or within 100 ft in same antenna farm. The analog signal looks great all the time. I've tried minute touchup of the antenna direction with little success. I've tried with an amp, with out an amp, on a diffierent cable run from the splitter in attic and still no success. I haven't found any others with similar problem in FAQ's or other forums. The antenna has some "harmonic suppressors" on it which I'm guessing is two short flat pieces of metal pointing forward from the terminal screws where the balun hooks on to the bowtie. Would this have an affect considering the frequency? I'm at whits end right now and it really works great for the NBC affiliate Chnl 15. An engineer at the station says that if I'm picking up the analog I should pick up the digital.
I'd really appreciate some help and I don't have access to a signal level meter, but am positive I'm within a degree or two of the antenna farm.

John
#2
Hi--
Try within those various menus via the Remote for "digital settings,,," or something similar. There, or perhaps after you are "on" that specific channel, there should be a "diagnostics" available...which tells the station channel, frequency, signal-to-noise ratio,,,so on AND, finally, a 'click' to get ...Strength...again, your menu wording may be different.

Anyway, this will give you part of your answer...namely, is it above say 60 %... if not or if it varies, then it will not "lock".

You said ...splitter... on this same COAX line...? Another set on same antenna line sometimes means "difficulties" with "HD" reception....if NOT an extreme hassle, try running an unspliced length from that balun transformer @ antenna connection directly to RF input... for a small $$$ increase, many stores now also sell pre-made lengths of "QUAD" COAX...total footage should be under 100. Also at web sites such as the one below.

Have you tried www.antennaweb.org to see what type & distance --( gain )-- antenna might be preferred for your ZIP Code? Another is
www.antennasdirect.com
eliwhitney
#3
Eli,
Thanks for your reply. I couldn't find my Radio Shack catalog to give the correct antenna. Well, I found it this AM and the antenna is a VU-190.
I'm absorbing all your information. I took the other set off of the other run from the splitter (coaxial) and ran a lead to the HDTV and it didn't help.
I'll have to go through the menu's and see if I can find the section you speak of and see what I can find out. If my problems were caused by the splitter and another set, don't you think it would affect the other channels as well as 15. I can pickup a channel 23 rock solid with an amp in line as well as a 21. The only problem I see with my installation is that I have the amplifier close to the set. As soon as the attic cools off her in southern Alabama, I'm going up in the attic and move the amplifier up there which will require some power run. The reason I will move it up there is so I'm not going to amplify noise and have a better SNR. I wish my "creeky" old body was more well preserved. I'll post my results.
#4
Hi--

Just a "thought"---every once in a blue moon, one finds a "HD" channel which is assigned to a VHF frequency...our local ABC is...
This would be confirmed / refuted by that ...antennaweb...site.

One other reason for the problem to be with only 1 channel would be IF that channel is transmitting with significantly less power (wattage)...this, too, will be listed on that web...

Anyway, in our case, an old Yagi antenna ( both VHf / UHF ) happened to solve our outside antenna issues. Yes, that AMP needs to be at antenna....
#5
Hi,
I went through all the settings looking for one that might give me something that would be similar to signal strength but couldn't find one for the user. I don't know if they have one even.
Now for the telling moment, EMBARASSED is the best word to describe it. I don't know if that is the fix, but it seems to be as we've had thunderstorms with upwards of large amounts of lightning strikes in the area and channel 15.1 and 15.2 has hung in there. As I was going through the various menus I came across time zone, and almost didn't check it because I knew I set it for Central, but low and behold when I opened it it was on Pacific(I think). So, I reset it and BOOM my problem seems to be solved. I hope it is a lasting fix and has been good for about 3 hours now. I've been shutting it on and off and seems to come right back onto the correct channel. Again thanks, as I'm super embarassed. I still plan to move the amplifier though.

John
#6
I hate to burst your bubble but changing the timezone would have no effect on OTA reception (at least not in any way I can think of). Either resetting it fixed it or something else happened. Do you know the physical channel number for 15.1?
#7
Thanks for the input. The physical channel number is 47. My reception has "gone south" again this afternoon. I looked at the radar and it is raining fairly good there at the antenna farm. But the other channel that this station has is really good yet. Fill me in please on this physical channel association. I'm not familiar with it as the UHF designation for my problem is 15. I'm anxious to find out!
#8
Your zip code sure would be helpful to all... :wink:
#9
ATSC allows multiple virtual channel numbers to be assigned to a single physical channel. In your case the station broadcasts on UHF channel 47. Period. That's what your antenna picks up. When the receiver decodes the digital signal it might contain one (15.1), two (15.1, 15.2) or more virtual digital channels. Think of it like multiple computers at home sharing one internet connection. Typically the station uses the same virtual channel number as their NTSC channel number (analog) to avoid confusion.

If none of your physical channels are lower than channel 10 you might try a channel master 4228 UHF antenna. It will pick up the higher VHF channels (I know it works for VHF channel 10 - that's what we have here in Atlanta for our NBC DT station). 7777 pre-amp is optional.
#10
My zip code is 36575-4523
#11
I've got channels 3, 5, & 10 on the VHF band. The UHF section of my antenna has 14 reflector elements and 15 director elements with a bowtie in the axis where the balun attaches.
#12
About a year ago while I was still in the shopping mode I found a dealer that had some sets on display that he let me "play" with. In other words, check out the menu's and controls etc... The set was on an antenna, but wouldn't pick anything up. He let me have the ops manual and in it, it was mentioned to set the time zone when initially setting up the unit. I did and then stations started coming in. That is why I mentioned about correcting the time zone setting.

Still getting much pixelation on 15.1 (47) this morning. Basically unviewable. I'm open to any and all suggestions.


John
#13
You could get a UHF antenna cut specifically for channel 47 and add that to your existing antenna setup if that's the only channel you're having problems with. Or get the 4228 for UHF and keep your existing one for VHF only.
#14
I like your idea, what would be your suggested method of keeping the one coax run and joining the two antennae together?
#15
You have to add a filter so that you don't get the same channel from 2 different sources that would interfere with each other. e.g. if you're using separate UHF and VHF antennas you could block UHF signals on the VHF coax and vice versa on the UHF coax then you combine them with a diplexor so you still have the one coax feed.

If you have an antenna cut just for 47 then you may or may not need a filter on the main antenna. Probably depends on how strong the signal is for 47 and if other nearby channels are affected.
#16
John- The
#17
First of all I'm going to check what coax I have on the VU190 run. I know I put RG6 on the DishNetwork when I installed that, but I could have RG59 on the VU190. Then I'll put the Channel Master in the attic and see what I've got.
Right now the attic is still running about 130 degs and the pitch on my roof doesn't permit me to walk or stand straight. After major back surgery about a year and a half ago I'm going to take it easy up there. To put the amp up there I've got to hook it up to some AC power first.

When I was pricing the 4228 at a local dealer which I knew from my days before retirement I mentioned my problems with the specific channel and he wasn't a bit shy about mentioning how that station has some big problems and I wasn't the only one with problems. So, I'm probably going to slow down a bit and go and see him one day and find out what is up. I think he didn't want to elaborate on the phone.

I think I will be able to disconnect the electrical connections for the UHF portion of the VU-190 and then connect the 4228 there with the proper baluns. I shouldn't have to put it on a rotor as all the UHF are in same area as the VHF in our market. There is two VHF slightly off the bearing to the problem child, but they are much closer and haven't ever been a problem. What do you think of that disconnection?
#18
The preamp power is supplied at the receiver end, not the antenna end. You won't need power at the antenna. At least not for the 7777.

The 4228 is fairly directional and might need a rotor but you can always try it without one first.
#19
OK looking at your area you will have 3.1, 10.1, 15.1, 20.1, & 42.1 are one direction. The stations 13.1 & 19.1 are about 170 degrees to the other side. The reason I mention this is that to get all of them you will have to have to antennas with filter combiner or a rotator to get all of them. All of the channels are UHF except 10.1 which is transmitted on VHF 9 most good UHF antennas would still get enough signal to pick it up. Transmitted power for the 15.1 & 15.2 is broadcast on channel 47 at 1000kw. At 40.5 miles it should be receivable but it also depends on terrain and housing around you. There is a really possibility that you have a multi-path problem that is killing you. In the latter case you will need an antenna that has a tight pick up area. Using Google maps I got a general area picture. Can;t tell for sure but looks like that are metal warehouses in the area that may be causing possible multi-path. You will have to find this out yourself since all I can do is look at the overhead view of Google maps. I looked up the VU-190 antenna should be a very tight beam unit. How high off the ground is it? Like I said above you will need a rotor. So that's my 2 cents worth.
#20
I also have a 5.1 in the area and it is at 27. But, it shares a location with 10.1 and 42.1 on that antenna farm. It is about half the distance as the other stations with a slight bearing difference. 44.1 (45) is very near the same location as 15.1(47) and comes in good as well as another station 23.1. As I mentioned in the last post I'm thinking 15.1 has some other problems. I'm not interested in 13.1 and 19.1 as I'm getting so many in the direction I'm pointed now and they are coming in great. The reason I'm so hard after 15 is because it is the only NBC affiliate around here.

Does anyone have any thoughts about electrically disconnecting the UHF portion from the VU-190 at the terminals and then adding the 4228 with a balun to these terminals? That way I'll be running just one coax?
#21
Sounds like it should work. Only one way to find out.
#22
Does anyone have any thoughts about electrically disconnecting the UHF portion from the VU-190 at the terminals and then adding the 4228 with a balun to these terminals? That way I'll be running just one coax?

John- If the 4228 is connected in parallel to the VU190 it will interfere with the VU190 in unpredictable ways. The way to achieve one feedline is to use the CM7777. It has a built-in VHF-UHF combiner, and its VHF input will ignore any UHF signal from the VU190. -Ken
#23
I thought he was talking about disconnecting the UHF portion of the VU190 and connecting the 4228 to the same balun where it would be combined with the VHF portion of the VU190. So the 4228 would just replace the UHF part of the VU190. Why wouldn't that work?
#24
Akirby- Assuming the UHF part of the VU190 is removed, and assuming the 4228 does not radiate (is highly reactive) at VHF frequencies, the 4228
#25
If you are going to get the 4228 then just remove the VU-190. The lowest frequency is 9 the 4228 will pick it up well enough with out the need of the VHF section. Also I recheck your location using the plus 4 on the end of the zip and everything is coming into your location w/ in a 15 degree arc. How high can you mount the antenna in the air? Are those metal greenhouse all around you? If so that could be a source of mutli-path that could be giving you problems?
#26
If I got much higher with my mast I'll have to add guy wires and I'm following the KISS principle right now. There isn't any green houses near me. You must be looking at a satellite shot of the area; most of them are from around 2002. The only thing metal around here is a storage shed about 100-150 ft away from the house.
When is the shift to UHF suppose to happen? In 2009?
Thanks for all the input as all this good stuff is getting as long as my "honey do list". I'll keep you posted.
#27
There is no shift to UHF. The analog cut off date is 2/17/09. there will be no channels above 52 in the TV band after that. Many of the broadcasters will start transmitting on their present analog channel in digital.
#28
My intentions are to disconnect the UHF portion of the VU190 and replace it with the 4228 electrically.
If looking at the terrain from a satellite shot, my zip probably put you at the post office which does have green houses near it. I'm about a mile ENE of the post office.

Again, thanks for the input.


John
#29
Based on what Ken said you'd need a VHF filter for the 4228 and a UHF filter for the vu190 before combining them to avoid interference.

Or you could just try the 4228 by itself.