>From: die@cpoint.clearpoint.com (David I. Emery) >Newsgroups: rec.radio.shortwave,rec.ham-radio,sci.electronics >Subject: Monitoring Air Force One Communications - End of an era >Keywords: 27000 28000 X-Band Milstar Nationwide Autovon GEP >Message-ID: <7230@cpoint.clearpoint.com> >Date: 31 Aug 90 06:29:04 GMT >Sender: die@cpoint.clearpoint.com >Followup-To: rec.radio.shortwave >Organization: Clearpoint Research Corp., Hopkinton Mass. >Lines: 46 The new Air Force One, a 747 with tail number 28000, has been delivered to the Air Force and is currently conducting tests prior to being used to carry the president for the first time. It appears that this aircraft will use multichannel X-Band DSCS (7-8 Ghz) or millimeter wave (20 and 40 Ghz) Milstar satcom for its primary voice/data links to the ground, relegating the 225-400 MHz UHF-FM-FDM Autovon GEP circuits and the 415 MHz NBFM "Nationwide" circuit to the same low priority, infrequently used, backup role as the traditional HF SSB "Mystic Star" channels that are still kept up to AF-1 for communication coordination and emergency backup. This means that in the next few days a 27 year long era will draw to a close for radio hobbiests; it will no longer be possible to listen in on much of the telephone traffic (almost all but the secure satcom) from the presidents plane as it flies overhead. This marks the passing one of the last "in-the-clear" federal communications systems carrying genuinely interesting traffic that can be monitored with simple equipment; although the UHF-wideband FM GEP Autovon and nbfm Nationwide circuits will supposedly still be maintained to the plane and may carry occasional traffic, it will likely be very low level, routine, and infrequent. For many years (from the 60s to the early 80's) the secure circuits from the plane were often of such poor quality (1200 baud vocoded voice was used for several years using first generation vocoders designed in the 60s) that many presidential calls were routed over the Autovon and Nationwide channels, and even in the last few years quite a few presidential calls have showed up on these clear circuits, especially on the Autovon (the "Alpha" and "Bravo") channels. For those who enjoyed such things and knew about how the circuits worked there was some interesting listening, especially in the early days of the systems before the introduction of usable secure satcom for high level calls. So thus passeth into cryptographic obscurity one of the most interesting remaining open federal circuits. Soon the only interesting easily received US government signals in the clear will be NOAA weather broadcasts, NASA Select TV and Wefax transmissions. I am sure that there are those at NSA, IRAC and the White House Office of Telecomunications Policy who are saying it's about time this was true. -- David I. Emery Clearpoint Research Corp. 35 Parkwood Dr, Hopkinton Ma. 01748 +1-508-435-7462 {m2c,frog,harvard}!crackers!cpoint!die, Internet: die@clearpoint.com