Spread spectrum would have more promise as many stations could be on the air at once on the same frequency thus making life quite confusing for the T-hunters.
I investigated this application several years back and see two practical approaches: one adapt a commercial SSB or Ham transciever to use frequency hopping spread spectrum, or two build a pirate spread spectrum satellite ground station. Until recently most SSB gear didn't have the RF characteristics to use FH. Now there are a number of inexpensive sets which use direct frequency synthesis (as opposed to the older, and much slower, phase-locked loop approach) and can be driven at hundreds or even thousands of hops per second. FH helps solve two problems: first it provides privacy, second it can mitigate or eliminate fading (which is highly time-frequency correlated). Also, the higher the hop rate, the higher the process gain, jam resistance and the lower the probablity of intecept (all other things being equal). It think it was Phil Karn (Qualcomm) who once mused that it would be rather straightforward to masquarade a high process gain SS signal on a commercial satellite transponder. To it's owners the SS signal would be almost invisible, making itself known as only a very slight depression in the transponder's gain. Effectively, this could offer an inexpensive covert channel for tunneling packets and thwarting traffic analysis. After the Captain Midnight episode I discussed this possibility with a very technically knowledgeable staffer at the FCC and was assured that discovery of such signals were beyond (at that time) the ability of commercial and national technical (e.g., Lacrosse) means. There's much more, but this should give you the general idea. --Steve --------------------------------------------------------------------- reply to schear - at - lvcm - dot - com --- PGP mail preferred, see http://www.pgp.com and http://web.mit.edu/network/pgp.html RSA fingerprint: FE90 1A95 9DEA 8D61 812E CCA9 A44A FBA9 RSA key: http://keys.pgp.com:11371/pks/lookup?op=index&search=0x55C78B0D ---------------------------------------------------------------------