Question about a new antenna

[wkomorow]

Because it was unlikely that I would be getting a couple of my HD channels via Dish anytime soon, I had a crossfire antenna 3677 and channel master 7777 oreamo professionally installed. I live in a valley about 40 miles from the transmitters with lots of mountains between me and the towers. To my surprise I get signal strengths in the high 60's and 70's on my 722 and also on my 622 Dish receivers. But I am having two problems.

First, all the transmitters except wypx are on the same antenna farm in the Heiderbergs. However, I am not able to receive WRGB (39) WCWN (43) and WYNA (15), but WTEN (26), WXXA (7), wmht (34) WYPX (55), wnyt (12) all have the same signal strength of 68-72 on my dish receivers. Numbers in parentheses are all real and not virtual channel numbers.

Second, wten will be on for 15 minutes and the signal will then drop to 0, then it will be on for several hours and then drop out, channel 34 also gets dropouts but less so, 55 even less so, 12 even less so, and 7 will have blocking but never goes to 0. The problem seems to be greatest during the day.

The installer tried over pointing the antenna (which should have ok directionality to begin with) to try see if that would help. The stations are at about 10 o'clock and he pointed them up to 11 and down to 9. We disconnected the pre-amp to see if that will help.

WRGB and WXXA are the two most important because they are unlikely to be on Dish in HD. After Feb, WRGB-HD will be on real channel 6-1. Since the VHF seem less affected, things may be fine then.

He suggested that the problem might either be multipath because of the valley, or WCDC (34 digital, analog 19) which is about 13 miles a way and transmits to most of western mass and southern vt and even NH, might be overpowering the antenna. Channel 19 is about 2 o'clock. If it is overpowering the antenna then again I should be fine come Feb. I can not receive 34 - it has 0 signal.

Also in the equation are a radio FM antenna at about 5 o'clock so behind the antenna and a metal cage over the chimney (in front of the antenna) to keep animals out. There are trees, but no building taller than 2 stories.

I am also getting a converter box to see if that tuner exhibits the same issues.

Because I can no longer walk steady enough on a roof, I will need to get someone back.

So my question, is what are the best guesses before getting someone else to look at the situation?

Thanks.

 

[Radioguy41]

I am in a similar situation. Directly in front of my house, less than 3 miles, is a mountain and my antenna would have to be 687 feet high to clear the mountain. However, due to a quirky property of digital signals they have something called "knife-edge deflection". That means that the signal deflects downward as it skims over a mountain. There's good and bad in that. The good is that you can receive signals that you would not think you should be able to (and sometimes, by tilting the antenna upwards to point right at the top edge of the mountain, you can actually gain more). The down side is that that deflection is susceptible to weather conditions and one other thing. That other thing, and something that drives me nuts, is airplanes. Anything that flies between me and the towers disrupts the signal. Unfortunately there is a perpendicular flight path just the other side of the mountain and if aircraft are approaching from the west my signal breaks up. Also, the local hospitals added helicopter service which flies right across the path. In addition there are numerous military flights through the path, especially A-10's that like to skim the ridge. They all cause the signal to break up (that's the beauty of digital tv vs analog. Analog would just fade a bit but remain watchable, digital just disappears).

These are just a few things to think about. The cage on the chimney could be causing an issue. I have a C-band 7.5 foot dish in front of, but below, the antenna. If I move the dish while watching TV from the antenna, the signal breaks up until the dish stops moving and the dish is a good 100 feet in front and 10 feet lower than the antenna.

 

[Tower Guy]

So my question, is what are the best guesses before getting someone else to look at the situation?

What does the data for TV Fool - Home look like at your location? You can click on "save image", and post the image back here.

 

[wkomorow]

Thanks jeepguy - we do get planes, which I can see at night but not during the day. The funny thing is that I have been watching the Olympics on channel 12 and get some blocking, but few drop outs. 7 is almost drop out free, 26, I can watch before 7 AM without drop outs, but can not watch it over 5 minutes during the day.. Notice 55 is way down on the list but is one of the stronger stations. 20 years ago I could get up on the roof myself - not going happen now with my knees - I am just not steady enough anymore. So the question because how much I want to spend to make this right. I have hired an installer - be here in two weeks - who is actually an engineer - so we will see. Could a ham radio be blowing my signal away?

Tower Guy = Here is what TVfool says. I think I can also point toward Springfield 156 range and pick up those channels, but I really do not want to put a rotor on given that all the major networks are on a single tower near Albany - I am just getting half of them reliably.

 

[Radioguy41]

I read through your original post looking for what tuner you are using. I have an older Sanyo HDTV STB and it does a decent job but I recently bought a couple of Zenith DTT-900 DTV converter boxes. I'm using the same pre-amp (mast-mounted) that you are and with the new (5th generation) digital tuner in the Zenith box I'm pulling in almost twice as many channels as the Sanyo. In fact, I'm pulling in Scranton/Wilkes Barre on the backside of the antenna while the Sanyo can't do it from the front side. It could be that your problem is related more to the age of your tuner than it is to the antenna. Just a thought.

The Zenith box does a great job of pulling in signals but, of course, it down converts the signal to 480. I've been looking at a new HDTV tuner (Samsung DTBH260F) that Circuit City sells for about $150 after rebate. I need to research it a bit more but it looks like it might have the latest generation tuner in it. All the reviews I've read indicate it does the job better than older boxes. If you want an HDTV picture this might be the way to go.

By the way, I added an 18DB distribution amp which helped stabilize some signals (I'm splitting it 4 ways) but also added a funky sideways jump to a couple of channels. Gotta work on that. I think maybe an adjustable amp might do it.

 

[Tower Guy]

Tower Guy = Here is what TVfool says. I think I can also point toward Springfield 156 range and pick up those channels, but I really do not want to put a rotor on given that all the major networks are on a single tower near Albany - I am just getting half of them reliably.

Springfield stations are even weaker than Albany's. I wouldn't bother with them.

WRGB switches to channel 6 in February. According to tvfool, the predicted signal level goes up by 25 db at your house. There will be three remaining UHF stations on the main DTV tower in Albany, but WTEN is duplicated on WCDC; leaving only WMHT and WCWN as your potential problem stations.

 

[wkomorow]

Thanks guys. I was hoping WRGB would improve when it moves to a VHF station in Feb. I am using a 722, but I also have a TIVAX STB-T9. Splitting the signal to both does not seem to decrease it from running to just one box. My TIVAX STB-T9 is reporting signal strength of high 50s for 7,12,55, mid-40s for the rest. WRGB has a signal strength of about 15 but of course will not lock.

WCDC is in a strange direction without a rotor. My original installer thought its analog signal my be overpowering my antenna.

I may end up putting a rotor on it when the new installer comes, maybe he can try an angular point.

Once I get a more stable situation, I will probably replace my TIVAX STB-T9 with a HD box. I will look at the Samsung.

 

[Tower Guy]

I may end up putting a rotor on it when the new installer comes, maybe he can try an angular point.

You could also opt for a second small UHF antenna for WCDC with a Jointenna tuned to channel 36. Unfortunately, a Jointenna on 36 may hurt WMHT-DT on channel 34. A trick is to get a Jointenna tuned one channel higher (37). Yet a 37 Jointenna would interrupt WRGB prior to 2009. Channel Master JoinTennas

Your installer is probably right, the strong analog signals from Mt. Greylock can interfere with WRGB-DT's channel 39 and WMHT-DT's channel 34.

 

[elder]

I get analog Ch4, Ch7 and Ch13 easily with a folded dipole, but digital is a whole 'nother story in the mtns of WNC. Digital Ch4 (Ch59) required an elevated and amplified Antennas Direct 91XG (Ch4 goes to Ch36 upon transition) , digital Ch7 (Ch53) I can't get (but it will go back to Ch7 so there is hope), digital Ch13 (Ch56) requires turning the 91XG 90 degrees (it's going back to Ch13 so it's a wait and see). I get multipath on occasion and today's antenna pointing may not work tomorrow.

 

[wkomorow]

I resisted a rotor because I DVR everything and winters here are very icy. That was a mistake because at least I would be able to repoint. The antenna is at 21 ft and looks over the house. What is very strange is everything will be fine for a while, then nothing. Even stranger, I got wktv (digital 29) from 130 miles away for two days (day and night), but still can not get wrgb (digital 39) from 30 miles away. Even stranger, I need to look through wrbg's towers to see wktv.

 

[elder]

Here's a photo of my set-up which is subject to change at transition time. On top is the 91XG, below on the same mast is an old Radio Shack antenna. I am using only the folded dipole on the Radio Shack, I am not powering its amplifier I just have a Dollar Store balun hanging off the dipole so I can sum it with a LaCrosse which you can see just beyond the mast. The 91XG is amplified and used for Ch4 (59) and Ch13 (56), not seen in the photo is a wooden handle I use to turn the mast 90 degrees when I switch between Ch4 and Ch13. The 91XG is also used for Ch33, and in addition I get Ch21 and Ch62 off either antenna (analog or digital). The Radio Shack and the LaCrosse are summed in a Dollar Store splitter and used primarily for analog channels. The two coaxes go inside to a switch near the TV. It's all a bit complicated right now, but I'll sort it out into a usable configuration when I analyze the reality after transition.

Note the trees, about the same in all directions to towers. The foliage gives me rain-fade and multipath when it rains. Better reception when trees are bare.

 

[wkomorow]

Thanks for the pic, I will see this weekend if adding a rotor will help me. I resisted because I really want this simple and I want to be able to DVR.