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Cell phone repeters

Old 03-13-2003, 05:37 AM
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nchrome
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Default Cell phone repeters

Ok you guys I have a little delima at my door steps or field. They just decided to build one of those repeters for cellphones exteremly near our field. This sunday all the club members are going to go out there and see weather or not if we will be sancaing our field this year. Cause I sure don't want to send 60.00 to the AMA just to find out that we won't be able to fly at our field any more. A couple of the guys say they have been flying there after the tower was put up. But that was before it was activated. The guy that lives near the field can't watch his TV any more cause he will have to go to satilite. What do you all think. Now this tower is about 50 to 100 ft from our field. Too close for me to fly my planes.
Old 03-13-2003, 11:45 AM
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Cactus.
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Default Cell phone repeters

OOOPS, just hit it with a Correx plane, oops, did it again, ooops, it fell apart must stop using it as a plyon turn.
Get some guys to put planes on the ground near it and turn them on. not the TX's tho. now make a few mobile calls and watch the planes. The frequencys used are much higher than RC, but you never know. theory has it the the TX memory can be wiped if a mobile is used right next to a turned off tranny. never seen it happen tho.
Old 03-13-2003, 12:41 PM
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sswagerty
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Default tower

I would contact your local ham radio club and have them bring a spectrum analyzer to the field. this should give you some data on what you are going to encounter...maybe:-)
Old 03-13-2003, 02:04 PM
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joeyM
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Default Cell phone repeters

I dont think it should be a problem--cell phone usage is around 800mhz--the frequencies we fly on are in the 72 mhz band----I think you should be ok
Old 03-13-2003, 03:10 PM
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Deadeye
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Default Cell phone repeters

Originally posted by joeyM
I dont think it should be a problem--cell phone usage is around 800mhz--the frequencies we fly on are in the 72 mhz band----I think you should be ok
I think it's the pole itself, not the possible interference. Anything sticking up by a flying field will get hit. It's a plane magnet.
Old 03-13-2003, 03:15 PM
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Tippie
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Default Cell frequencies

Analog cell phones operate on 824-894mhz and PCS cellular (Digital) operates on 1.85-1.99ghz (1850-1990mhz), thus dual band cell phones. The chances of hitting the tower (50-100 feet away) are probably greater than being shot down by the transmitter. Certainly if you fly in close vacinity of any transmitter antenna (I'm talking a few feet, depending on transmitter power), regardless of frequency, it will cause RF overload and block the signal to the receiver. As far as the TV interference, that person should have contacted the tower installer and had them install a filter on the television. Ham radio can also cause TVI and the offending Ham will install a filter. Doubtful that the cell tower will cause any problem other than be an obstruction in flying, which itself is not good. Cell phones (handheld) operate at two different powers levels, .6watts and 3watts. If cell frequencies are a problem you should ban cell phone use at your flying field also.
Old 03-13-2003, 06:33 PM
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Default Cell phone repeters

The good news is (if you want to call it that), a repeater does not put out as much power as a regular cell tower (the most I have seen on a repeater is 20 watts (~70 watts including antenna gain)). But then again, there are just too many variables involved to know if it will really be a problem. The easiest way may be to have a sacrificial lamb and fly circuits around the tower.

FYI-if the tower is designed like it should be, there would be less RF above the tower (sites are designed to propagate the signal towards the ground where people are, but then again, I did not design this one so I do not know for sure).

BTW- I have never heard of an 800Mhz or PCS frequency interfering with a television station. I do know that towers can and do interfere with certain broadcast frequencies (if its too bad they will have to detune the tower). In most cases people just went with cable or satellite.
Old 03-14-2003, 03:57 AM
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CCRC1
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Default Cell phone repeters

Something else you may need to consider. A cell telephone company may have erected the tower but other private or government repeater antennas may have leased space on it. I know that Cell One erected towers on property owned by the local county school board and were allowed to do so with the agreement that local public safety could also mount their repeaters on the same towers. It saved the county quite a bit of money when they were upgrading their communication systems. So it may not be just cell frequencies broadcast from the tower.
Old 03-14-2003, 04:10 AM
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rc-sport
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Default Cell phone repeters

We have a cluster of cell towers about 200 yards behind our flight and we don't seem to have any trouble. Every once in a while when someone dumb thumbs one in the blame it on interference from the cell towers.
Old 03-15-2003, 01:10 PM
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Jim C.
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Default Cell phone repeters

ahahahahha no they should not cause interference but i agree with the scrificial lamb suggestion tho just to be safe. the place we fly at here we have a 15 million dollar windmill like 250 yrds away from our flight line but we fly oppisite of it due to the location of the sun but i sure dont want to be the one that had to pay 300,000 bucks for a new carbon fiber blade they are as big as 2 school busses!!! i think you should be safe around the tower
Old 03-17-2003, 11:30 AM
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Jimbonk
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Default Cell phone repeters

CCRC1 has the correct answer, it's not the Cell Phone Tower you have to worry about , it's the other stuff that can be hung on it.

The ONLY Commercial Radio Signals RC'ers have to worry about are PAGERS. They operate in between 2 R/C channels. The good thing is you will only lose the use of two channels .

Jim B
Old 03-17-2003, 04:09 PM
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wildnloose
 
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Default Cell phone repeters

While what Jumbonk says about paging systems is true, its not gospel. Case in point, I had to troubleshoot an interference problem we were having with a nationwide paging company (sorry, the name escapes me but I think its Skytel) that has been deploying paging systems nationwide on an experimental PCS license (2Ghz) putting out massive amounts of power (2500w erp w/60mhz bandwidth).

From what I conlcuded, any receiver (from pcs down to cb band) within 100 ft was overloaded (anything higher than 2Gzh does not seem to be affected).

Like sswagerty says, get a spectrum analyzer and see what you have, its best to err on the cautious side.

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