On 9/10/98 10:28 PM, Robert Hettinga (rah@shipwright.com) passed this wisdom:
Hey, guys,
Someone here already said it, but nobody else got it, so I'll repeat it: SSB, or Single Sideband. It's commercial ham radio, if you will, and all the ships use it. I expect that you can shove anything down an SSB set that you want, including encrypted traffic.
Ham radio is a government nerd subsidy, and as such, doesn't do much but make more government funded/sactioned/approved/whatever nerds. :-).
SSB would do just fine. It's an international standard, after all, and probably not under the control of any one government, even.e
Bob, I am afraid you are showing your ignorance here. SSB is just one of the many modes of emission standardized in radio communications, its used by the amateur radio service (ham) , the citizens radio service (cb), the military, etc ... The real problem is that to build any sort of network would require some fixed positions, which, if it were intended to be 'clandestine' would be compromised sooner or later ... either that or several poor shnooks would have full time jobs driving vans around and around to keep the RDF snoops guessing ... In general there would be a better chance of pulling it off if you stayed away from the ham radio bands. 'self-policing' is not a character of another bands except the commercial broadcast bands. 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. Brian B. Riley --> http://members.macconnect.com/~brianbr For PGP Keys <mailto:brianbr@together.net?subject=Get%20PGP%20Key> "I would rather be exposed to the inconveniences attending too much liberty than those attending too small a degree of it." -- Thomas Jefferson
At 8:24 PM -0400 on 9/12/98, Brian B. Riley wrote:
Bob, I am afraid you are showing your ignorance here.
I don't think so.
SSB is just one of the many modes of emission standardized in radio communications, its used by the amateur radio service (ham) , the citizens radio service (cb), the military, etc ...
I know what Single Sideband means. As I've said before, and what you failed to read later on in this thread, evidently, is that there are commercial Single Sideband radios out there which have the range of ham sets. These radios are used for commercial ship-to-shore traffic, and I expect that encryption is legal on them. I expect that, because these frequencies are subject to international convention rather than federal law, they have more leeway (heh... nautical pun) on their use. Including, I bet, digital packets and encryption.
The real problem is that to build any sort of network would require some fixed positions, which, if it were intended to be 'clandestine' would be compromised sooner or later ... either that or several poor shnooks would have full time jobs driving vans around and around to keep the RDF snoops guessing ...
My understanding is that Ryan's looking for some kind of post-infocalyptic radio network for when it All Falls Down Sometime Soon (tm). I expect that in that event, Ham would be fine, because there is no, as Mr. Gore likes to say, controlling legal authority, to worry about. But, to put up and test a network, commercial SSB would do just fine. And, of course, After The Big One, what kind of long-distance shortwave radio you run it on will be superfluous, ham, SSB or no.
In general there would be a better chance of pulling it off if you stayed away from the ham radio bands. 'self-policing' is not a character of another bands except the commercial broadcast bands.
Right, so (he says for the third time), why not just order a commerial ship-to-shore SSB rig, something which costs within an order of magnitude, plus or minus, of a Ham set, and go play?
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.
Right. If we had some, um, ham, we could have some ham and eggs. If we had some eggs. Cheers, Bob Hettinga ----------------- Robert A. Hettinga <mailto: rah@philodox.com> Philodox Financial Technology Evangelism <http://www.philodox.com/> 44 Farquhar Street, Boston, MA 02131 USA "... however it may deserve respect for its usefulness and antiquity, [predicting the end of the world] has not been found agreeable to experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'
"Bobby" == Robert Hettinga <rah@shipwright.com> writes:
My understanding is that Ryan's looking for some kind of post-infocalyptic radio network for when it All Falls Down Sometime Soon (tm). I expect that in that event, Ham would be fine, because there is no, as Mr. Gore likes to say, controlling legal authority, to worry about.
Worse, there may be any number of "controlling legal authorities". You don't suppose that all the existing radio monitoring equipment is going to stop working just because the infrastructure for managing it is in disarray? Or that people with access to that equipment are going to have any problem getting fuel for their helicopters from government fuel dumps? But your communication network is going to become a valuable resource, and more than one tin-pot wannabe is going to want to get his hands on it.
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 ---------------------------------------------------------------------
participants (4)
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Anonymous -
Brian B. Riley -
Robert Hettinga -
Steve Schear