Fond du lac, WI: help setting up roof antenna - AVS Forum
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post #1 of 13 Old 08-18-2012, 08:08 AM - Thread Starter
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so i did the tvfool and antennaweb map lookups and unfortunately i cannot get up on my roof at this time (no ladder and my neighbor wouldnt let me borrow his....) but we have 5 antennas on the roof all pointing diffrent ways for the most part. It is a house with 4 apartments in it. as far as i can tell 3 wires or so go into the house in the two upstairs apartments, i seriously doubt if they use them becasue 2 of the wires come down into the basement under my apt and both are cut dead. So i got matching transformer hooked it up to one of the flat wires and a 50ft rg6 coax and had my tv scan for channels and this is what i got:

1 channel: 5.1
sig str: 0-30
phy ch: 90
freq: 621000 khz
mod: 8vsb
errors: 0-12713 dec
snr (db): 15.5 db
agc: 100%
this was unwatchable, signal lost every 3 seconds or so

then i switched the matching transformer to the other flat wire and got this
3 channels 2.1,2.2,2.3
sig str: 59
phy ch: 74
freq 525000 khz
mod: 8vsb
snr(db): 18.5 db
agc 100%

now as far as i can tell those 2 channels are in the same location/ close in the band with so idk why im not getting both of them on the same one, here are my tv fool results:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d990062c824eed8

basically i want as many channles as possible, right now im expecting to have to get up on the roof, move the antenna and install a powerful preamp/fm filter.

any help on what i should do? that tv fool result is like greek to me, but i will say that two of the antennas look like they are pointing north/north east towards the greenbay stations. ill try to get a pic of the roof for you guys with all the antennas if that will help, im thinking all the antennas up there is not helping signal either...thank you !
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post #2 of 13 Old 08-18-2012, 08:56 AM
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Based on the physical channels your TV is reporting you are scanning cable TV channels. You need to change the scan to over the air or antenna to do the scan correctly.
Your FOX channel is in the high VHF band and the rest of the major networks are UHF all are showing signals strong enough so that a properly aimed moderate sized UHF VHF hi antenna should receive them without too much trouble. Posting a picture of the antennas would be helpful. When you do get on the roof first replace all of the flat cable with coax and aim the antennas properly and see what you get.
John
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post #3 of 13 Old 08-19-2012, 05:59 AM
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Thread title edited to add location as specified in the sticky post. Please add a location to ALL antenna help threads. Thanks.

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post #4 of 13 Old 08-19-2012, 11:56 AM - Thread Starter
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ok so here is a picture of my roof

2012-08-18-190100-1.jpg

and i switched my tv to cable off and re did auto program to find channels over the antenna it was pretty close to before but values were different. so this is what i got now

on the one cable i got 4 channels
2.1,2.2, 2.3, and 11.1
2.1 channel diagnostics
strength= 75
phy ch= 23
freq= 527000
status= lock
SNR= 21db
AGC= 96%
all of the channel 2's were perfect
and channel 11.1 was terrible, maybe 1 sec of video every minute

the second cable i have coming down from the roof got me this:
1 channel 11.1
11.1 channel diagnostics
strength= 67
phy ch= 11
freq= 201000
status= lock
SNR= 19.5 anywhere to 20.5db
AGC= 84%

now my confusions comes in because as far as i can read the tv fool results i posted earlier, these 2 channels are extremely close in distance and angle....maybe im wrong, i dont understand why im only getting on channel on either of the two cables and not both channels on both cables. at this point im thinking i need to drill a hole by my tv so i can use a 6 ft coax cable instead of 50ft after my matching transformer the splices the 2 lead 300ohm to my new rg6. that should help with signal loss, also a fm blocker as they are cheap enough. For installing preamps should they be up on the antenna? or could i install it where the 2 lead wire comes into the basement? if it has to go up on the antenna i wil wait untill i drill hole and shorten cable length and can actually get on the roof to tweak the antenna direction to see if i can get 11.1 on the antenna that is getting 2 and 11 terribly, i was thinking of following the two wires to their respective antennas and moving the the one that gets 4 channels slightly in the direction of teh one that is getting only 11.1 and fanagling it untill i get as many channels/strongest sig str possible, then install a pre amp.
Is there a better way to align the anteanna, i.e perfectly with compass?

thank you so much everybody for your help and support
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post #5 of 13 Old 08-19-2012, 08:12 PM
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Until you know which antenna you are using, get it properly aimed and properly connected you cannot really expect to be able to predict what will come in. Even stations of the same strength will not come in the same if the antenna is not aimed in the correct direction. The two stations you are getting are on different bands so I would expect them to be received quite differently although your reported SNR is very close for both of them and small differences cause big differences in picture quality near the minimum useable signal. This is referred to as the cliff effect for digital reception.
The two antennas on the left are VHF only and will not likely work for most of your stations. I am not sure but the left ones may be parts of larger antennas that have broken. Either of the two on the right are probably OK. Try one of them after getting rid of the flat cable. You can use a compass to due the initial aiming and tweak the direction around the compass heading and see if you can get any improvement. A preamp may well help but I would give the antennas a try without one and see how it goes.
If you can't get to the roof a shorter cable might give a little improvement as would a preamp connect as close to the antenna as possible (at the antenna when you can get to the roof) which would be right at the end of the flat cable.
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post #6 of 13 Old 08-21-2012, 07:19 PM
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It's difficult to tell from the pictures, but if I had to guess, I would say that the reason there are so many antennas is that the goal was to get Milwaukee and Green Bay TV stations without a rotor, and I am wondering if each pair of antennas is actually combined together on the roof.

I will say that the flat cable is probably killing any signal the antennas might be seeing. You're going to have to replace that to get anything usable out of the antennas. I also agree that the antennas on the left look broken, but the ones on the right don't look to be in bad shape. I would be interested to know what reception would look like with new cable hooked to JUST the top right antenna, with or without an amplifier. I am thinking it would bring you most of the Green Bay stations.

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post #7 of 13 Old 08-22-2012, 05:09 AM
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A few questions:
Which 2 antennas in the picture on the roof are you testing? It could be you only got 11.1 and not 2.1 on the 2nd cable because its connected to a VHF only antenna ( 2 antennas on the left mast in the pic)
Also you mentioned you have 5 antennas on the roof, where is the 5th one in the picture?
Looking at the picture , where is the house's orientation? Anotherwords if I was looking out the window with the A/C on the 1st floor where you marked the red lines, what direction would I be looking at?
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post #8 of 13 Old 08-23-2012, 06:31 PM - Thread Starter
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the window with the a/c is facing south, i was thinking that the two antennas on the right are the ones the wires are going to as far as i can tell, and it does look like one is pointed to milwaukee(south, and a tad east) and green bay(north, little east). Im in the process of trying to borrow a ladder, how do u suggest i work up there on that pitch? ive done 2 roofs before and this one looks unwalkable, i dont wanna have to use roof jacks frown.gif
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post #9 of 13 Old 08-23-2012, 06:37 PM - Thread Starter
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and i guess there is only 4 antennas smile.gif haha i was guessing before i got a good look, once i get up there do i use a matching transformer(thing with 2 prongs on one side and female coax on other) on the antenna itself then coax the whole way? or do i have to use 2 lead 300 ohm wire coming off the antenna for a foot or so then change it over? and how do i read the tv fool results and line the antenna using a compass? that is confusing to me, thank you so much guys
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post #10 of 13 Old 08-25-2012, 07:25 AM
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Safety first. If you don't feel comfortable on that roof, do not go up there!
Yes you will need to go from coax all the way down.
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post #11 of 13 Old 08-30-2012, 05:24 AM
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1. According to your TV Fool report, there is only one low band station (5), so those larger tri-band antennas are (for the most part) a waste.
2. Not knowing how old they are, it's safe to assume the baluns are bad and probably so is the coax, or at least should be replaced, especially if it is RG59.
3. I assume you don't own the house? If not, does the landlord have ladders? You would need two, a 28' (maybe 24', but I doubt it) and a 2nd shorter one as a roof ladder (using only one of the two sections) with a hook attached for the peak.
4. What is your neighbors objection to you using his ladder? That is assuming you are versed on ladder safety and don't have any issues on going up on a roof. wink.gif
5. No one uses 300 ohm twin lead anymore (except for special applications other than TV).

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post #12 of 13 Old 09-06-2012, 04:46 AM - Thread Starter
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Thanks for all the help, my stepdad will help me get on the roof(he is a roofer) i took a look at the base of the mast with the 2better antennas using a binoculars and i saw 2 manilla colored boxes the wires went into. Im thinkink splice box or ancient amp?
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post #13 of 13 Old 09-06-2012, 04:54 AM - Thread Starter
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Quote:
Originally Posted by videobruce View Post

1. According to your TV Fool report, there is only one low band station (5), so those larger tri-band antennas are (for the most part) a waste.
2. Not knowing how old they are, it's safe to assume the baluns are bad and probably so is the coax, or at least should be replaced, especially if it is RG59.
3. I assume you don't own the house? If not, does the landlord have ladders? You would need two, a 28' (maybe 24', but I doubt it) and a 2nd shorter one as a roof ladder (using only one of the two sections) with a hook attached for the peak.
4. What is your neighbors objection to you using his ladder? That is assuming you are versed on ladder safety and don't have any issues on going up on a roof. wink.gif
5. No one uses 300 ohm twin lead anymore (except for special applications other than TV).
.

If all of channels are high band except one shpuld i consider a preamp? Im only going to have one afternoon to up ony roof i would like to b fully prepared for those precious hours smile.gif
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