i8bla@vax87.auc.dk (07/21/89)
In article <Jul.19.14.48.15.1989.439@athos.rutgers.edu>, gutherz@athos.rutgers.edu (Matt Gutherz) writes: > > A while back (months) there was a discussion about improving > radio reception in basements etc. Someone posted a solution > using 2 antenna and some coax. Does anyone have the posting > or know the specs for the antenna? Thanks in advance. > > > Matt gutherz@jove.rutgers.edu Radio propagation inside buildings. The system you mention is probably the 'leeky feeder'. This can be used in tunnels, where you place an antenna outside to pick- up the radio signal, an retransmit it on the coax cable. If the cable has some slots, you will experience an electromagnetic field, radiating from the cable. The problem is to get a field with no severe power fades. Such systems are already imple- mentet in Europe, retransmitting FM radio broadcast. I have an extra question: Does anyone have any experience in radio propagation inside buildings at 2 GHz as a function of building materials? (Bricks, concrete, reinforced concrete, wood, glas etc). I would be glad to hear about any practical experiments or theoretically modelling. Bo L. Andersen Aalborg University Denmark
roy@phri.UUCP (Roy Smith) (07/23/89)
In article <81@vax87.auc.dk> i8bla@vax87.auc.dk writes: > The system you mention is probably the 'leeky feeder'. This can be used > in tunnels, where you place an antenna outside to pickup the radio > signal, an retransmit it on the coax cable. If the cable has some slots, > you will experience an electromagnetic field, radiating from the cable. The Port Authority of New York and New Jersey does this in the Lincoln Tunnel. Interestingly enough, my reception is *better* in the tunnel than outside. It's probably because I've got a trashy AM set which barely works and in the tunnel there is less random interference. The interesting part of the system is the the PA can break into the normal re-broadcast for emergency messages. They do this, I believe, on every AM channel. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 {att,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@alanine.phri.nyu.edu "The connector is the network"
john@stiatl.UUCP (John DeArmond) (07/24/89)
In article <3890@phri.UUCP> roy@phri.UUCP (Roy Smith) writes: > The system you mention is probably the 'leeky feeder'. This can be used > in tunnels, where you place an antenna outside to pickup the radio > signal, an retransmit it on the coax cable. If the cable has some slots, > you will experience an electromagnetic field, radiating from the cable. This is known by the brand name Leakiax. It is standard fare in most of the nuclear plants I've work. It is used to provide 2-way radio contact in all the shielded rooms in these plants. The Leakiax I looked at consisted of 7/8" hardline with a narrow longitudinial slot cut in the shield. This slot was segmented into sections about a foot long. Don't know if this was some sort of tuning or just manufacturing convenience. -- John De Armond, WD4OQC | Manual? ... What manual ?!? Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You ...!gatech!stiatl!john **I am the NRA** | just GOTTA Know!!!
gutherz@athos.rutgers.edu (Matt Gutherz) (08/16/89)
A while back (months) there was a discussion about improving radio recetion in basements etc. Someone posted a solution using 2 antenna and some coax. Does anyone have the posting or know the specs for the antenna? Thanks in advance. Matt gutherz@jove.rutgers.edu