I need advice please!!!!

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scannerman200

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My apartment landlord let me put a scanner antenna on the roof of the apartment building I live in. I'm gonna say it is about 16 foot off the ground & is mounted to a ventilation pipe on top of the building using plastic ties bec the u-bolt was too big. We ran the cable down from the roof to the scanner. The reception is not that great & does not pick up farther. What should I do???
 

scannerman200

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One continuous cable, bnc connector on the part that goes to scanner, & I am using a radioshack vhf/uhf outdoor antenna - $26.99. The antenna is mounted on the backside of roof, not actually topping the roof
 
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N_Jay

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What band are you listening to?
What type of cable?
How much farther are you trying to pick up?
 

scannerman200

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Well, I mounted the antenna to a 5 foot pole & mounted the pole on a ventilation pipe with tie straps. Reception is stll scratchy, but it is very cloudy outside. Would the clouds affect the reception?
 
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N_Jay

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So we know the type of antenna, but not the band you are listening to.
We also don't know the type or length of cable.

Without this type of information you will only get "wild guesses".

With it we may be able to get to reasonable guesses.
 

kb2vxa

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There's part of your problem right there, the coax you're using sucks raw eggs on those frequencies. You really should be using RG-8 type such as Times Microwave LMR-400 or equivalent, 58 is just fine for mobile use though since rarely more than about 18' is needed.

The other half of your problem is lack of height and you can't use more than a 10' mast on a vent pipe safely. Uh oh, plastic ties are the WORST possible way of mounting it, they were never meant to stand the strain and worse, they deteriorate quickly when exposed to sunlight. Large metal compression type hose clamps are not a good idea either, while they'll stand the strain the mast won't stay upright any more than it will with tie wrap, neither are designed to withstand lateral stresses. Why didn't you use a vent pipe mount in the first place?

Oh I almost forgot! All is well if the pipe is metal and there are no joints above the roof line BUT if it's PVC forget about it altogether. Put lateral stress on that stuff and it will snap, particularly if it's old because the older types tend to get brittle with age. In any case be grateful your landlord allows this and keep him happy by not causing damage of any kind, not in the slightest.
 
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scannerman200

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Well, I guess I'm out of luck. Radioshack only carries 10-feet of RG8 cable. Maybe the reception is bad because of the cloudy skies we've been getting. As I stated earlier, my local frequencies come in clear, its just when I monitor a distant station, lets say 20-30 miles, you can hear frequency, but it is static in the background.
 
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N_Jay

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It will make about a 3 db improvement.
You might hear the difference, but just barely.

Height is king, but as you go higher and use more cable the cable becomes more important.
 

prcguy

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There are formulas for figuring out height vs cable loss and for a flat urban environment the point of no return at VHF/UHF is about 8dB of cable loss regardless of cable type.

Use lower loss cable and you can go higher before the loss ads up.
prcguy


It will make about a 3 db improvement.
You might hear the difference, but just barely.

Height is king, but as you go higher and use more cable the cable becomes more important.
 

kb2vxa

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Oh here we go with another techie war, they'll argue this to death as always. Since Rat Shack isn't up to the task and you don't seem to know of another source I'll recant my previous suggestion and go with the RG-6 crowd. Sorry it didn't cross my mind at the time but it's the cheap and dirty way of doing it and FYI the quad shield is pretty much as good as you can get before you get into the fancy and expensive stuff. You can get it, the required F connectors (a little bigger than for regular 6) and a crimping tool for a song at Home Despot, Wally Mart or other similar outlet. Then go on line and order the appropriate adapters, cheap enough and you're in business.

Since you're new to the game and nobody mentioned it yet don't overlook the need to waterproof all outdoor electrical connections. Cheap, off brand black vinyl electrical tape is best for the job because it stretches better than 3M for example so wrap them tightly stretching as you go fore and back forming an overlapping double layer. Start a couple of inches down along the cable, work upward to the very top of the antenna connector covering exposed threads and back to where you started leaving the last turn slack, not stretched. The reason for this is the tape will want to shrink and you don't want the end coming loose and flapping in the breeze. Hey, if it works for the Army it'll work for you and last many years.
 

k9rzz

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If I may ... what scanner are you using? 20 - 30 miles is a haul on VHF and a real haul on UHF depending on how hilly the terrain is. (it doesn't matter if it's cloudy or not). Try the RG6 upgrade, that should help but 'noise free' reception might be asking too much.
 

prcguy

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What techie war? And Scotch 33+ electrical tape stretches and seals better than any other brand I have found, even in freezing weather.
prcguy


Oh here we go with another techie war, they'll argue this to death as always. Since Rat Shack isn't up to the task and you don't seem to know of another source I'll recant my previous suggestion and go with the RG-6 crowd. Sorry it didn't cross my mind at the time but it's the cheap and dirty way of doing it and FYI the quad shield is pretty much as good as you can get before you get into the fancy and expensive stuff. You can get it, the required F connectors (a little bigger than for regular 6) and a crimping tool for a song at Home Despot, Wally Mart or other similar outlet. Then go on line and order the appropriate adapters, cheap enough and you're in business.

Since you're new to the game and nobody mentioned it yet don't overlook the need to waterproof all outdoor electrical connections. Cheap, off brand black vinyl electrical tape is best for the job because it stretches better than 3M for example so wrap them tightly stretching as you go fore and back forming an overlapping double layer. Start a couple of inches down along the cable, work upward to the very top of the antenna connector covering exposed threads and back to where you started leaving the last turn slack, not stretched. The reason for this is the tape will want to shrink and you don't want the end coming loose and flapping in the breeze. Hey, if it works for the Army it'll work for you and last many years.
 

GKolo

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Does Radioshack stock the standard F to BNC and F to PL249 adapters ? Kmart here has 50 feet of RG-6 with gold plated conectors for 19.99 .....
 
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