antenna

XWrench3

Daemon Poster
Messages
813
Location
W. MICHIGAN
40+ years ago, i was part of my high school audio-visual team. back then, the coordinator was a great guy, always challenging us to learn more. i had a lot of interest in building a long range radio antenna, for listening to music. anyway, i was not as successful as i wanted to be, because my dad would not let me mount a huge array on the roof of the house. so i compromised, and made a decent antenna from the clothes line we had in the back yard. anyway, now days, my family live out in the bush so to speak nearly 50 miles from the closest tv station. when we moved here, there was a tv antenna mounted to the roof, but it had seen better days (branches had dropped onto it) and it did not do a very good job of pulling in any stations. so i just said hooey on it, and ordered cable. well, at least in this area, the price of cable has since tripled. and honestly, i could buy one heck of an antenna for one months bill. but there are SO MANY trees between here and there, i am not sure (especially in the summer with 40 billion leaves in the way) how well a normal tv antenna will work. one of the things i had thought about back in the day, was using a dish antenna. but dad said no to that as well, since they were 5 feet across. this morning, i had an idea, but i do not know enough about these to know if it would work or not. what about one of the smaller "dish tv" antennas? would something like that work for receiving hdtv? i do not know how much different satellite wave lengths and hdtv waves are. and i do not know if that small dish reflector would be big enough to catch a full wave this far out. i would have to have a 40'+ tower to get a clean shot at a regular antenna. but i can now at least mount anything i want on top of the roof. which would give me about 25 feet in elevation at the peak. also, the peak of the second story has no tree limbs near it, so i would not have to worry about damage other than wind damage or lightning strikes. any idea if this will work? or what modifications i would have to make?
 

setishock

Wizard of Wires
Messages
10,726
Location
4321
You can use the dish but not the LNA. The LNA is tuned to microwave frequencies and is useless for OTA signals which are in the lower band. Take pictures with a ruler in the shot to measure the distance from the deepest part of the dish to the LNA. That's the reflective focal point of the dish. The reflected signal is focused there. Of course different frequencies have different focal points but that will give you a starting point.

Remove the LNA but not the mounting boom. Attach an antenna tuned to the local TV band. You'll have to ask a TV tech or Google around what frequencies are used in your local area.

Aim the assembly toward the station you want to watch. Keep in mind a dish that small is going to be a royal PITA to aim. Plan to spend a couple of hours on the roof tuning the focal distance and getting it pointed in the right direction. A pair of cheap walkie talkies would be very helpful unless you want to drag a TV up on the roof. Make double damn sure your feed cable has a lightning bug in it and it's ground lead goes as straight as possible to the ground rod your meter is on. No sense going to all that trouble to get a picture just to get everything blown up in a lightning strike.

Make sure to use silicone sealer under the dish mounting plate if you move it. Seal up the old location with some tar or squirt some clear silicone in the holes so they seal up good. Don't get it on your clothes as it being water proof, it doesn't come out in the wash. Put a liberal coat of silicone on the bolts before running them in. Seals up the bolt holes right nicely.

Last sage words of advice. When on the roof keep in mind you're on a roof. Keep your situational awareness. You said it's 25 feet up. If you fall from that height you can get seriously messed up or dead.
 
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PP Mguire

Build Guru
Messages
32,197
Location
Fort Worth, Texas
One thing to note, is if you're 50 or more miles the chances of getting good digital reception is slim to none unless you live in a very flat area with little to no trees/brush/buildings in the way. Depending on where exactly you live your TV stations will vary greatly. You say one is 50 miles, but another station could be 100 or whatever away. Digital TV signal has to have a very strong signal for it to not break up due to the way they send the signal vs analog. It was changed to reduce white noise found on analog but the problem is having less signal can make it worse causing the actual picture you watch to stop, pause, break up, and artifact constantly.

From what you're saying the odds of getting a good signal even from the one TV station closest to you is slim to none. Even after all the work you might get signal but it may or may not be actually watchable. To give you an example, when they went digital my dad put up a 40ft pole and mounted a very large TV antenna on it with hopes of getting better reception. To his dismay, it didn't work. Texas isn't as flat as most would think, but it's not like we have mountains or anything. The majority of long range antennas are on a large hill very high in the air (these towers are freakin HIGH) only about 20 miles away from the house. They also lived on a hill compared to the surrounding area with little to no trees to block reception and literally 0 tall buildings in the way. The reception was piss poor to put it mildly. It was pretty much unwatchable.

Using a dish might help with that one channel, but then if you want other stations you'll need to make a motorized contraption to move the antenna to increase signal from other possible locations with the hopes you actually pick them up. It's honestly not worth the effort.

If your cable has "tripled" and you have a bunch of packages you might consider dropping channel packs you don't watch. Another option is to check out Sling TV and sign up for a Netflix account. Those two combined are cheaper than most all cable packages I've seen, even the cheap ones. I consider 150 HD stations for $30 cheap on my service, but Netflix and Sling is cheaper together. (For the record, I don't pay for TV service)
 

XWrench3

Daemon Poster
Messages
813
Location
W. MICHIGAN
if it was just me and the kids, it wouldn't even be an issue. but my wife lays in bed all day watching tv. she has physical problems, so she is not able to get around much. i really do not watch a lot of tv. but what i do, is on either history or discovery. we have what they call "basic" tv, and it is in the $100.00 a month range. they KNOW we do not have much choice, so they put the screws to us. and there is no other service that comes to our area. i was told that someone in our local govt gave this company exclusive rights, but i do not know if that is true, or how to check it out. even if it is, there is probably not much we could do about it.
 
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