Re: radio net

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

> 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

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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.