Problem getting Channel 12 in Phoenix AZ

niv

New member
#1
Here’s my location report

TV Fool

I am in the east valley, Phoenix AZ on the “other” side of the mountains with the TV transmitters on South Mountain 29 miles away. Channel 12 has been a problem child for me. When fully deployed I have a Winegard HD7698P Antenna on a 40’ tower (part of it buried) with a 30 foot retractable mast. It’s about 58’ AGL. Currently it’s around 32’ because I have the retractable part down. I’ve been meaning to replace the guy wires and with the monsoon season in play, now is a good time to have it down to do that. It will be put backup for football season at the end of the month.

At 32’ I get all the stations in the 226º direction except for Ch 12 and Ch 3 (24). at 58’ I get all the stations. The mast has gotten blown over several times over the years for various reasons. After the last time (3 years ago, roofers undid a guy wire and a storm suddenly blew in) I put it back up to around 54’. That lost Ch 12. I thought it had to do with the antenna or wire or something. Took me about a year to remember that I hadn’t put it up to the full height. I don’t rely on OTA for my local viewing, I have Dish. Once I put it up to the full 58’ I got Ch 12 back on the main TV. Secondary’s are Visio TV’s which seems to need a stronger signal for their tuner than LG so channel 12 is a no show on the Visio’s. Main TV is a LG 4K, I love to watch live sports via OTA vs Dish because the up convert to 4K is dramatically better. Regular TV shows are watched via the Hooper to skip commercials so OTA is only for live sports at the moment.

There is a house that is just up the street / hill that is blocking Ch 12. When it was a vacant lot I got everything from South Mountain with 2 or 3 (can’t remember) good old Radio Shack 10’ antenna masts mounted with an eves mount on the side of the house. Now it has to be 58’ to clear the neighbors house. A head scratcher is that at the 32’ height I’m not picking up Ch 3 (24) which is 29 miles away in the direction the antenna is pointed but channel scans are picking up Ch 4 (23) which is 58 miles at 112º (Tucson, opposite direction). It doesn’t come in very well, but it will occasionally drift in where as 3 (24) does not scan in.

I am assuming that the frequency of Ch 12 is susceptible to things like houses blocking it. I would like to get a stronger more reliable signal on Ch 12. I have just stated experimenting with the Plex DVR (SiliconDust HDHomerun Extended with commercial skipping) and since Dish has started charging extra for locals I’d love to tell them where they can put their locals.

In the early days, pre tower, I had a preamp on the antenna which actually degraded the signal because of the signal overload on most of the channels. I don’t think a preamp is an option. The cable run from antenna to the home distribution amp (Channel Plus DA-506BID) isn’t excessive and back when I was trying to get Ch 12 back at the 54' height I replaced the cable as a home-run RU6 vs the splices that were in the old one. Seems like it’s in the neighborhood of 50’.

Channels I want to receive are 3 (24) Ind, 5 (17) CBS, 8 PBS, 10 Fox, 12 NBC, 15 ABC, & 61 CW. Of these channels, 3 (24) is the least important. Is there a higher gain VHF antenna besides the Winegard HD7698P that could improve the Ch 12 signal strength? I was looking at the Denny’s HD Stacker Antenna, is this a technology that might boost the VHF gain? Not sure of the science involved, it costs about as much as another Winegard HD7698P, could I stack 2 Winegard HD7698P for maybe more gain then the Denny’s HD Stacker or is there more involved than just putting 2 antennas on top of each other?

I’m trying to tune my installation up while it’s down to a workable height and would love to reduce my Dish bill by $12 a month while getting better picture quality. I’m looking for suggestion on how to achieve this goal.

Thanks for reading this.
 

dkreichen1968

Moderator
Staff member
#2
Here’s my location report

TV Fool

In the early days, pre tower, I had a preamp on the antenna which actually degraded the signal because of the signal overload on most of the channels. I don’t think a preamp is an option. The cable run from antenna to the home distribution amp (Channel Plus DA-506BID) isn’t excessive and back when I was trying to get Ch 12 back at the 54' height I replaced the cable as a home-run RU6 vs the splices that were in the old one. Seems like it’s in the neighborhood of 50’.
Were you running both the preamp and the distribution amp? That would explain why the signal was being overdriven. I'd consider replacing the distribution amp with a preamp, which would help preserve the signal received by the antenna before any cable losses. You're losing 2 to 3 dB of signal before it gets to the distribution amp.
 

niv

New member
#3
Interesting . . . Actually Solid Signals just had a sale on the Juice preamp that also has a LTE filter. It's due in tomorrow. I also got a variable attenuator which I was thinking I might be able to find the sweet spot coming down from the antenna to the distribution amp. I'm not sure the preamp could handle the split and run to the 4 TV's in the house but I'll certainly give that a try if I am again overloading the distribution amp even with the attenuator. Saw this technique on TV Fool. I'd love to post on TV fool, there seems to be lots of interaction with questions posted. I signed up 3 weeks ago and still haven't been activated. Seems it takes weeks for a moderator to go over the new accounts which renders the site kind of worthless for a quick answer. I saw potential problems when I was first looking through and getting my site report. I thought, hey I've got a month. My antenna goes up next week, it's football season for heavens sake. :) Probably won't get the benefit of any advise from them. Thank you for your input.
 

dkreichen1968

Moderator
Staff member
#4
Unfortunately we haven't been as active as we were in the past. Interest in DTV has seemed to have waned. For the moderators here also. ;) If you look at the TVfool website they give a equation for figuring how much gain you need for your system. 1 dB for every 18-20 feet of cable plus 3.5 dB loss for every split. dB predicted + gain of antenna + gain of amp - noise figure - total loss of the system = dB at the TV. They recommend 10 dBs at the TV. You can certainly overload a distribution amp. I've seen one fry its circuits from overload.
 

niv

New member
#5
I thought that the interest in DTV had increased with all of the cord cutters. That's what I'm trying to do. I'm locked into Dish for another year but now that they are charging separately for locals I'd like to get my OTA reliable to the point that I can drop the locals and do some of their modular stuff that they have designed for the "cord cutters" which is why they say they've split out the locals from the packages. Anyway, can the DA take 10db? The PA is 16db gain. With the attenuator dialed in half way that would probably hit the DA between 8 and 10db. Then again I'm not sure what the gain is from the antenna. The PA won't handle the house, I'd lose more that half of the PA gain with just the split loss. Maybe if I can get as good a signal as possible to the DA the rest will fall in line. It would be nice to have a signal strength meter. There was a time that I had access to one but not any more.
 

dkreichen1968

Moderator
Staff member
#6
Let me know what happens. The main problem with double amplification is you are amplifying noise. The first amp produces noise and the second amp amplifies it. The noise degrades your signal quality, which is the main thing with digital reception. A weak clean signal is better than a noisy strong signal.
 

niv

New member
#7
It didn't work. Not much change in signal levels that I could measure with my rudimentary strength meter (EyeTV module on my laptop) and I lost a channel out of the deal. Just took it off line yesterday. I need to find a way to increase the antenna gain, if that's possible. I don't know if Denny's HD Stacker Antenna is a possibility, not sure of the science of that, or maybe stack another HD7698P could boost the gain???? Or just stay where I'm at, I don't know. I need to get it back up before too long.
 

dkreichen1968

Moderator
Staff member
#8
Have you ever tried the system without the distribution amp? Your TV fool indicates plenty of signal on channel 12. I know there are lots of other factors, but a noisy distribution amp could be a problem. Have you tried running to one TV to establish a base line before any splits or amplification?
 
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