I write long posts, too, so we can relax about that.
On September 13, 2013 at 15:33, SDShack said...
My location is North San Diego County, which puts me about 30 miles North of a VHF tower for CBS & ABC, and 40 miles Northwest of UHF tower for Fox, PBS, Independents, and NBC. I have always had cable for the 12 years I have lived here, so I never knew how OTA signals were.
This recommends that you get an antenna rotor if you cannot get good enough signal pointing in some one direction. I assume you have looked at tvfool.com or antennaweb.org to verify the directions to the transmitters. Just pretend you want to know what antenna to buy, put in your address, and let them work it out.
My house is 2 story, but kind of in a little valley, with a good size hill/plateau along the entire South skyline.
Could be a problem, might not be. It must be checked with a good antenna that you can point.
No one in my neighborhood has OTA TV antennas,
That just means they have cable or a dish.
so I decided to try a DIY Gapless Gray Hoverman design from John Davis, and modified it a little.
Excuse me, but I buy commercial antennas. I have had to supply antenna systems for retail stores, and the last three I did had more than four hundred TVs in each store. Plus 60 FM receivers.
My only failure was the inability to pick up KNSD (NBC) out of SD at about 40 miles. It operates at UHF 630 MHz, but only broadcasts at 18 kW ERP. The fact that I was able to get UHF stations above and below this frequency made me think that my antenna array is correct, but the signal is too weak.
Or the aiming is wrong. Or the antenna is too high or -- get this -- too low. It could be!
Then I made sure my compass direction was good for my house
The tvfool and antennaweb maps can be printed, and then you can stand on the roof and orient the antenna with relationship to the street!
etc etc So I added a folded dipole 18" above my Gray Hoverman, and aimed at 180 degrees and immediately added those stations, plus a couple of VHF from LA for a total of 25 stations now.
This is sounding pretty good overall.
In summary, my current system is mounted on my roof, about 5' above my chimney. It's a modified gapless Gray Hoverman aimed at 153 degrees with a folded dipole on top aimed at 180 degrees. Each antenna has a 300 ohm cable, and both of these cables are attached to a single Balun,
How? Are the cables paralleled? For best isolation they should each be converted to 75 ohm, then those outputs run backwards through a splitter to combine them. This might give you overall higher signal level.
that connects to 40' coax (2-20' cables with a connector), that attaches directly to my HDTV - no cable box. My only problem that I need help with is I still can't get NBC out of SD, but can get the other UHF stations that broadcast from the same tower.
Be sure when you write SD that nobody thinks you mean standard definition. I did for a moment there.
That leads me to 3 questions:
1. Is my inability to pick up NBC because the signal is too weak? If so, can that be solved with some type of signal amplifier, and if so, what is a good recommendation? Note- several weak stations from LA are strong enough for my TV to "tune them in" during setup,
What is "setup"?
but too weak to broadcast a picture when I select the channel. With this NBC-SD problem, the TV has NEVER once tuned in this station, let alone broadcast a picture.
Is it possible NBC in LA might do for you?
2. Is there a better commercial antenna out their that could solve my problem rather than going with the DIY route? If so, what are the recommendations?
My favorites are the Channel Master CM2016 or CM2020. The Winegard HD8200U has been THE CHOICE for getting stations 75 miles away for more than twenty years. However, you must compare the antenna's channel frequency capability with the channel frequencies you're looking for. That NBC in San Diego might be on too low of a channel for the antennas you're dealing with!
3. This is a little off topic. Has anyone ever designed and used a bi-directional Gray Hoverman with a reflector? In my case, I am wondering if one array pointed NW 315 degrees (for LA), and one array pointed SSE 135 degrees) for SD with a reflector grid sandwiched between the 2 arrays would work to allow me to pull in stations from both LA and SD?
I have no experience with this. Know, though, that if the signal comes in straight and directly on one antenna, and also comes in near that signal level with a lot of echoes due to the signal being reflected off of hills and what not, those signals will be combined, lowering your overall signal quality for that channel. And when you have two antennas, every signal will be brought in off both antennas; problems only occur when one signal is crappy and near the signal level of the other. You can determine this on a clear day by recording whatever info you can about what stations you get; first with one antenna, then with the second, then with the combination.
As a result of this stufy, you might decide you want to switch from one antenna to the other. Private Message me if you want info on going that route. I might be able to solve the problem but you'll want to spend the time ( = $ ) gathering the raw information yourself.
Though one great antenna with a rotor is still a good answer: there's never any cross-contamination of signals and you can adjust the pointing while you watch.
And did I tell you I do antenna systems? I could come up with a method of switching antennas for you and install the darn thing.
