wolit (12/15/82)
There's good reason not to allow ham radios on airliners. The potential for messing up the cabin pressurization system isn't one of them. Sorry, Adam, but there's no way that could happen. Jan Woliztky
dwl (12/16/82)
In following up the reply to Adam's article, I don't think Adam meant that the HT was likely to have any effect on the pressurization controls. The problem is that if anything that is obvious to passengers DOES go wrong, the poor guy with the HT is going to be blamed for it! Mostly a PR problem for him, and for the airline who let him fly with it! -Dave Levenson -BTL Holmdel
avsdS:avsdT:wcl (12/16/82)
I haven't seen an answer to the original question, which is "if airline nav equiptment is so sensitive to RFI, then how much RFI does it take to mess it up?". In particular, can ground radios affect it, or does the faraday cage nature of the cabin keep the RFI out of the sensitive parts? And if so, what does that say about the new composite aircraft (such as LearFan) made of fiber/epoxy (no Faraday cage effect)? Also, what about calculators, computers, etc. I have heard that microprocessors, and radio receivers are banned for similar reasons, but I have yet to be asked to remove the battery from my digital watch for the duration of the flight. What's **REALLY** going on here? Is this just the FAA being Pleistocene? Bill Lindemann atd!avsdT:wcl AMPEX Corporation
jak (12/17/82)
As for other rfi, once while waiting for others to board a flight from Denver to Newark, I was speaking with the flight engineer requesting permission to "listen only" to my 2 meter ht during the flight. His comments were interesting ... He said that many times hand calculators and electronic games used by passengers during flights presented a significant interference problem to the instruments. He said that some times, some electronic games were so bad that they had to walk through the cabin looking for the offensive device and request that the passenger turn it off! Jim Kutsch WA8ZNH hou5f!jak
Schiller@MIT-MULTICS (12/17/82)
From: Schiller at MIT-MULTICS (Jeffrey I. Schiller) A VHF or UHF radio of sufficient power (and most HT's are) can mess up all forms of electronic equipment. Basically if there is a wire (or printed circuit run) that is just the right length, significant voltages can develope. I have seen 432MHz radios do things like cause train crossing gates to go down, and computer systems to crash. The reference to a cabin pressurization system came out of a recent issue of QST magazine. The aircraft I believe was a 747, which has a fairly sophisticated automatic pressure regulating system that could be knocked out of kilter by a UHF radio at close range. -Jeff