Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!cbnews!cbnews!military From: amichiel@rodan.acs.syr.edu (Allen J Michielsen) Newsgroups: sci.military Subject: Re: CNN & battelfield communications Message-ID: <1991Jan24.040852.23085@cbnews.att.com> Date: 24 Jan 91 04:08:52 GMT References: <1991Jan18.003548.8604@cbnews.att.com> <1991Jan22.015042.19969@cbnews.att.com> Sender: military@cbnews.att.com (William B. Thacker) Organization: Syracuse University, Syracuse, NY Lines: 41 Approved: military@att.att.com From: amichiel@rodan.acs.syr.edu (Allen J Michielsen) In article <1991Jan22.015042.19969@cbnews.att.com> stevew@wyse.wyse.com >>From: att!druhi!fidder >>Question on battelfield communications. >>I was under the impression that when we attacted Iraq that all forms of >>electronic communication would be jammed. How is it that CNN was able > >The CNN crew was using a commercial portable satellite uplink system >to talk out of Baghdad. This is a micro-wave system which involves >aiming the ground station dish at the satellite. The only way >to jam such a system would be to send a signal on the same frequency >aimed at the satellite that was significantly stronger than the >ground station being jammed... Close, actually sat uplinks are (fairly) low power all things considered, quite directional, and subject to swamping by all kinds of ground 'clutter' including jamming by nearby signals. Depending on the location of the cnn uplink disk, the direction or sat that disk was linked with, and the surrounding (s) around the dish, it may or may not have been swamped either on a single channel or completely. Even if BBC used the same sat, but a different uplink dish at a different location, then bbc could have been jammed and cnn not. (The other could be be true too). The number of variables is huges, but common sense prevails. The signals (and jamming) are terribly directional and affected immensely by local conditions and locations. Even disk design could have been a factor. We have a disk that is located on a building, in the flyway of a ground telephone MW link. We have gotten the disk to work nearly perfectly by adding mw absorb cow flops around the outside edge. Another possibility, I haven't looked at, is the possibility that cnn was using a K band instead of C band (or backwards), while everyone else was using the other (if anything it's probably that way because of ted turner and the age of cnn compared to bbc). We are used to all the majors having and using both C & K bands, but over there, that case could well be vastly different. al -- Al. Michielsen, Mechanical & Aerospace Engineering, Syracuse University InterNet: amichiel@rodan.acs.syr.edu amichiel@sunrise.acs.syr.edu Bitnet: AMICHIEL@SUNRISE