[RFI] Cable EMI

[k0hzi@comcast.net]

Have a very strong signal from 145.520 to 145.540, it has some "buzz" noise at the edges and also there is a low level audio signal that corresponds to channel 23 on Cable TV.  Looked at Channel 23 in relation to amateur radio on the ARRL web site. Audio carrier is listed at 221.75 and video at 217.25.  Have taken my HT around the building and used a home made beam, but the signal seems to be radiating from every place in the building.  The building is a thirteen story high rise, it has a an open area in the center of the building from 1st floor to the roof, 50 feet by 50 foot square.  The only place I do not receive the signal is in one stairwell or if I leave the building.  As soon as I go to the lobby which is sealed from the inside by a space of about ten feet between lobby and interior of the building, then the signal disappears and also have walked outside the building, the signal does not leak out.  Have been on every floor, even taking the antenna off the HT there is 
 some signal on every floor.  Also at times there is a weak signal on 145.500, maybe from the same source. The interference sometimes causes weak stations on the local SSTV net and makes the image look terrible.  Any ideas?  What could be mixing with channel 23 to end up on 145.520 to 145.540?

Would make a good place to "shoot" internet Wi-Fi down from 13th floor, HI.

Jerry  -  K0HZI