Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!delta.eecs.nwu.edu!phil From: phil@delta.eecs.nwu.edu (Bill LeFebvre) Newsgroups: sci.space.shuttle Subject: Re: Shuttle communications Message-ID: <957@accuvax.nwu.edu> Date: 27 Jul 89 15:44:09 GMT References: <115800001@uxa.cso.uiuc.edu> <807@occrsh.ATT.COM> <7651@pogo.WV.TEK.COM> Sender: news@accuvax.nwu.edu Reply-To: phil@delta.eecs.nwu.edu (Bill LeFebvre) Organization: Northwestern U, Evanston IL, USA Lines: 23 In article <7651@pogo.WV.TEK.COM> bobt@pogo.WV.TEK.COM (Bob Tidrick) writes: >The S-band frequencies are: >... >For the non-DoD uplinks, the carrier >frequency of the downlink transmitter is phase locked to 240/221 times >the uplink frequency, also for tracking. While certainly challenging, this >is not outside of the capabilities of a dedicated amateur. As someone has pointed out, the next flight (as well as the one after it) are DoD: both uplink and downlink will be encrypted. Furthermore, they just recently decided to encrypt ALL uplink, even on the non-DoD. I don't know when they implemented this decision (whether it was on or after STS-26), but I know it happened. It is now beyond "the capabilities of a dedicated amateur", although probably not impossible. I think it was a smart move. Downlink for non-DoD flights remains unencrypted. William LeFebvre Department of Electrical Engineering and Computer Science Northwestern University