I have an fm antenna (low power) on the tower where I am at at about 35 feet above me and I have a CPE on an FM backup antenna with no problems. This is Axxcelera 3.65 wimax. Shielded cable with good grounds. No need for ferrite beads so far.
Sent from my iPhone4 On Dec 20, 2010, at 5:31 PM, "Leon D. Zetekoff" <[email protected]> wrote: > On 12/20/2010 05:56 PM, Jack Unger wrote: >> There is QUITE a difference between a separation distance of 20 ft and a >> separation distance of 100 yards. Remember the inverse-square law - RF >> intensity >> decreases as the SQUARE of the separation distance. 100 yards is 300 feet >> and 20 >> feet goes into 300 feet 15 times so the RF intensity at 100 yards is the >> inverse >> of 15 squared (15X15) or the inverse of 225. Inverting 225 means that the >> intensity at 100 yards is only 1/225th as much as at 20 feet. Scott's >> equipment >> is going to be exposed to 225 times greater RF energy than yours so his >> equipment is likely to be overloaded with receiver de-sensitization while >> your >> equipment may be OK. >> >> The solution is to "do everything right" as Scott says. The 11 GHz equipment >> is >> likely so far away from the FM and TV frequencies that it is probably OK. >> The >> solution for 2.4 and 5 GHz is use proper bandpass filters between the >> antennas >> and the equipment then test to see if the receivers seem to have full >> sensitivity or not. >> > Jack is 100% correct. Remember these radios do not have much filtering > in the front-ends so you have to make up for it with external accessories. > > Leon >> jack >> >> >> On 12/20/2010 2:34 PM, Bret Clark wrote: >> >>>> On 12/20/2010 1:30 PM, Scott Carullo wrote: >>>> >>>>> Ok, I've dealt with up to about 20KW on FM transmitter 20 feet away >>>>> and dealt with it decently. >>>>> >>>>> Now I'm told one of our installs of gear on a tower is about to get a >>>>> 100KW 20ft above my gear and a TV antenna 20ft below it at 700KW >>>>> channel 39 I think. >>>>> >>>>> Anyone have gear running close to this kind of high-power antennas? >>>>> Am I screwed or will I be able to have my equipment work int his RF >>>>> environment? Assume I did everything right (grounded metal box, >>>>> shielded cable soldered drain wires, ferrite cores on the cables etc...). >>>>> >>>>> Thanks >>>>> >>>>> Scott Carullo >>>>> Technical Operations >>>>> 855-FLSPEED x102 >>>>> >>> We are running 5.8 and 3.65 stuff on towers with 100KW TV systems on the >>> tower located about a 100 yards from us on another tower...no problems. >>> Probably not much difference between 100KW 20 feet or 100 yards apart. >>> > > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
