Satgen 5 .Strange satellites 435.974. Requests for summary of data. Herewith is summary I recently sent to Birger Lindholm in Finland. Birger was the satellite listener who first pinned down the orbits of these birds 1. What are these sats on 435.9744 MHz ? 2. One of them is in a typical Navsat orbit period 105 mins, inclination about 90 degs. Individual Navsats use one channel pair of :- Chan 1 2 3 4 5 6 7 8 149.91 149.94 149.97 149.978 149.982 149.988 150.00 150.03 MHz 399.76 399.84 399.92 399.941 399.952 399.968 400.00 400.08 MHz MilSov MilSov MilSov USN USN USN Op CivSov MilSov These frequency pairs are the 3rd and 8th harmonics of a roughly 50MHz original Eg 150 =3 x 50 and 400 = 8 x 50 MHz. So one might expect harmonics on :- 449.73 449.82 449.91 etc , ie the 9th harmonic ,but not 435.975 MHz 3. The suggestion that 399.974 ( not a regular frequency), becomes 399.974 plus 2 times 18 MHz = 435.974, via Intermediate Frequency Image reception , is a non starter because it ignores the mirror image rule of image reception which reverses sidebands and REVERSES THE DIRECTION OF DOPPLER SHIFT. These strange sats have normal (always going down ) doppler shift. 4. Navsats are usually launched and stored in orbit immediately they are built. This gets them past the dodgy launch phase and it provides ready use in orbits spares if an operational Navsat goes U/S. The US Navy put Oscars 25, 27, 28 and 31, into storage orbits in the recent past. There has never been any report of how they keep in touch with these stored birds. Are they using Amateur Band frequencies. The US Navy calls its Navsats "OSCARS", despite the fact that Amateur Radio has been using this title since 1961. So do not be confused by this double usage.US Navy Navsats were originally introduced as a vital feature of their Polaris Submarine Missile System. 5. It is possible that these satellites are Chinese. The Chinese have recently introduced Ballistic Missile Submarines, and Navsats are a vital part of SSBN Fire Control and Targetting System. 6. The biggest snag to the above is that two of these sats are in orbits with periods of about 101 minutes. This puts them at a much lower altitude than standard US and Russian Navsats. 7. Both the Soviets and the Americans are operating Polar Communications experimental sats. Very little is known about the Russian Cosmos 1809 or the American "Polar Bear" experiment, except that Polar Bear uses Navsat type Hardware and is said to be testing relay of compressed TV, which it gets from geosats and downloads to US Arctic Bases which the geosats cannot see. 8. It is noteworthy that these 435.974 Mystery sats appear to operate as a team on the same frequency. None of the explanations given in 1 to 7 above fits this aspect of the situation. It is possible that these sats are transmitting on other frequencies, but none have been reported so far. 9. Once the orbits can be described by accurate Keplerian elements it should become possible to identify the individual satellites as to launch, country of origin and reported function. So it is likely that we may eventually find out what they are, but it is far less likely that we will ever find out what they are actually doing. 73 de GM4IHJ 10 May 89.