I have a couple of questions. im putting up my new antennas, and i have a metal roof. how far above the roof do i need to mount the antennas? What kind of pole do i need to mount? radio shack has 10 foot sections for like 15 bucks, and i have 100 feet of heavy copper coax, how should i connect the vhf and uhf antennas together?
New setup questions
- Thread starter krisman
- Start date
- Latest activity Latest activity:
- Replies 19
- Views 2K
If the antenna is close to the edge of the roof that faces the transmission source, 6' away (radius) should be fine. What makes you think that you need seperate antennas? Are you sure you need a VHF antenna at all?
yep i am positive that i need 2, there are a few channels that broadcast on vhf in my area. so with my old wore out antenna, its mounted on a 25 foot pole and only a few feet above the edge of the roof, it is anchored to the edge as a matter of fact. so i need to go 6 feet above the edge of the roof, and then 5 feet between the vhf and uhf antenna? so that is going to be at least 35 feet of pole? so should i be looking at getting some kind of durable pole instead of getting 10 foot sections at radio shack?
You've made a good choice for your system: Separate, band-specific antennas outperform single, all-channel models almost every time.
It sounds as if the mast you have now is secured to the side of the house/structure. If that's so, and as long as it's bracketed near the roof line, another 10-foot mast section shouldn't wobble too much.
The best way of coupling VHF and UHF antennas depends on distance to the transmitters. If you're at least 35 miles away from the nearest station, an antenna pre-amp with dual inputs would do the trick. Top candidates are the Channel Master 7777 and Winegard AP-2870. If you're closer than that, a high-gain pre-amp may overload in the presence of strong signals, so it would be best to use a passive combiner such as a UVSJ instead. Either way, you'd run a coax cable from each antenna to the inputs of the pre-amp or UVSJ.
It sounds as if the mast you have now is secured to the side of the house/structure. If that's so, and as long as it's bracketed near the roof line, another 10-foot mast section shouldn't wobble too much.
The best way of coupling VHF and UHF antennas depends on distance to the transmitters. If you're at least 35 miles away from the nearest station, an antenna pre-amp with dual inputs would do the trick. Top candidates are the Channel Master 7777 and Winegard AP-2870. If you're closer than that, a high-gain pre-amp may overload in the presence of strong signals, so it would be best to use a passive combiner such as a UVSJ instead. Either way, you'd run a coax cable from each antenna to the inputs of the pre-amp or UVSJ.
The thumb rule is one full wavelength from reflective objects and other antennas. 6' is typically adequate. My real question is which market are you near that will still be transmitting on TWO vhf channels after June 12 of this year, and if you're that sure, are you sure that one of them won't be vhf-LO? Would you mind attaching the PNG image of your post-transition radar plot from TVFool.com?
TV Fool - TV Signal Locater
i really dont know how many or if any channels are on vhf hi. i just heard you can drag in more channels with 2 seperate antennas. the pole is mounted right where the roof slants at the highest point of the roof, im wondering if i can move the pole over a few feet, to where the roof is sloped downward about to where the guttering is, if that would save me a few feet in heighth? because i only have 100 feet of coax, about 40 would go toward the pole and antenna, which would leave me 60 feet, allow 5 feet from top of floor to the tv. that would only leave me 55 feet of underground coax, and i dont know how long it is to underground to tv, so im trying to save all the coax that i can, especially if i have to snip it for the preamp.
i really dont know how many or if any channels are on vhf hi. i just heard you can drag in more channels with 2 seperate antennas. the pole is mounted right where the roof slants at the highest point of the roof, im wondering if i can move the pole over a few feet, to where the roof is sloped downward about to where the guttering is, if that would save me a few feet in heighth? because i only have 100 feet of coax, about 40 would go toward the pole and antenna, which would leave me 60 feet, allow 5 feet from top of floor to the tv. that would only leave me 55 feet of underground coax, and i dont know how long it is to underground to tv, so im trying to save all the coax that i can, especially if i have to snip it for the preamp.
Holy Hell. Have you considered spending $20 per month to get Dish Network to sell you a Locals Only package? ;-)
no of course not, this is half the fun. you never told me what you thought of the extra vhf antenna, does it look like i need one? i got a 10 foot pole today, i think that will be enough to raise my antennas the 6 feet from the roof, and space them 5 feet apart like they reccommend. now can anyone tell me which goes on top and which on bottom or does it matter?
WDKY (Fox) will be Ch 4, almost 95 miles away, which is too far.
WTNZ (Fox) will be Ch 34, at 50 miles away, should have similar programming and more relevant weather.
WLJC (Ind) is also Ch 7, and is also 90 miles away, which is too far.
WMAK (Ind) will be Ch 7, but is less than 50 miles away, and is 100° off of WLJC's azimuth. But do you actually watch this?
These are the only VHF channels on your list. I'd ditch the VHF plans altogether, or at least focus on getting a working UHF solution, putting it at the top of your mast. There are lots of reports that 4-bay UHF bowties can pick channel 7 just fine at 50 miles. You are using a rotator, right?
WTNZ (Fox) will be Ch 34, at 50 miles away, should have similar programming and more relevant weather.
WLJC (Ind) is also Ch 7, and is also 90 miles away, which is too far.
WMAK (Ind) will be Ch 7, but is less than 50 miles away, and is 100° off of WLJC's azimuth. But do you actually watch this?
These are the only VHF channels on your list. I'd ditch the VHF plans altogether, or at least focus on getting a working UHF solution, putting it at the top of your mast. There are lots of reports that 4-bay UHF bowties can pick channel 7 just fine at 50 miles. You are using a rotator, right?
no im not using a rotAtor, i decided against one. i dont need the multiple stations like 3 different abcs and foxs and stuff as long as i can get one or 2 of each. and im mainly going for the south stations, i guess i will be putting up the vhf about 5 feet from the tip of the roof, the uhf about 5 feet above the vhf, and i have an amp that i got from radio shack, its a bit old but will it be ok? my pole is a little old too but i dont see a lot of rust on it. i think itll be ok, but i will need clamps too for my new pole and for the uhf? i have one for the vhf that it came with
The only in-store Amp I'm seeing at the Rad Shack web site is about $60. The Channel Master 7778 (aka Titan-II) is at Summit Source and Solid Signal for about $55 + S&H, and it'll do a better job than the Rad Shack unit will, for sure. It sucks that you've spent the money, but it's worth it to get the Channel Master.
ok dren, so you are saying to ditch the vhf, which i wont be able to get but 2 channels on which are duplicates.....lower my pole about 5 more feet to suffice for the empty vhf antenna......and get a pre amp and i should be all set? i was kind of looking at the winegard ap 2870 since it is in stock and everything, what is your opinion of this?
If you aren't already an avid watcher of WMAK programming, then yes, forget about VHF antennas. I would, however, put the UHF antenna at the tip top of whatever pole you have, because more altitude is always better (assuming it's rigid).
That Winegard amp looks like a good buy; it's hard to go wrong with Winegard or Channel Master. I wonder if it'll amplify or block Weather band...
That Winegard amp looks like a good buy; it's hard to go wrong with Winegard or Channel Master. I wonder if it'll amplify or block Weather band...
Last edited:
For low loss uhf transmission, your coax must have a foil shield layer, foam dielectric insulation and have an impedance of 75 ohms. Coax with copper braid only shield will be extremely lossy at uhf frequencies.
The resistance of copper braid is lower than the resistance of aluminum foil. With everything else equal, copper braid will have lower loss than aluminum foil.
Yet, it's a good idea to have the better shielding of a foil, especially with CATV systems.
Just asking, With todays technology if aluminum braid could be successfully crimped like copper and the resistance dropped would it be a useful to test a braid by its capacitance (to same)?
The capacitance of coax is related to it's characteristic impedance. All 75 ohm coax of the same size will have the same capacitance.
