<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<blockquote type="cite">
<blockquote type="cite" style="color: #000000;">
<blockquote type="cite" style="color: #000000;">
<pre wrap="">In the US, for example, even amateur radio operators otherwise allowed
to do way more than the general public aren't necessarily allowed to
transmit spread spectrum outside certain spreading codes.
</pre>
</blockquote>
<pre wrap="">Australian amateurs are allowed to use SS (and I have) provided the
authorities have been notified of the spreading code (which sorta defeats
the purpose);
</pre>
</blockquote>
<pre wrap="">Depends on what you think the purpose is. If it's to communicate through noisy channels, or just to experiment to improve or even just personally understand the technology, or to provide a public service - then it's within the ambit of the amateur services, at least as they are defined in the US. If it's defined to include secret communications, it's definitely outside the US definitions.
</pre>
<blockquote type="cite" style="color: #000000;">
<pre wrap="">we can also use crypto, for sensitive search and rescue
messages (and I have).
</pre>
</blockquote>
<pre wrap="">I'm not sure that's ever permitted in the US under any circumstances.
-- Jerry
</pre>
</blockquote>
<br>
In the US hams can encrypt under exactly one specified circumstance:
Control of a space station, meaning a radio station on a satellite.
That is presumably to keep "outsiders" from taking over control. In
general a US ham cannot transmit anything intended to conceal
information. (That exception is the basis for a question frequently
appearing on ham license exams.)<br>
<br>
Back during and at the end of WWI, the US Navy wanted control over
all broadcasting. That by itself has little to do with cryptography,
but a combination of that desire implying limiting what hams could
do and fear that uncontrolled radio operations could include spying
for foreign powers leads to this denial, which is a connection to
crypto. And it might explain why this restriction is not found (so
far as I know) outside the US. So spread spectrum cannot be used to
conceal anything. But the FCC rules governing the amateur service
specifically justify the existence and encouragement of the service
in large part based on the progress in communication coming from
hams experimenting and developing new techniques, hence exceptions
for experiments intended to improve technology.<br>
<br>
It is hard to write enforceable rules that say you can do X but not
if your intent is to accomplish Y, resulting in very specific
statements about what you can and cannot do: That implies they are
soon obsolete, hence need revision from time to time, and that is
definitely what has happened with respect to spread spectrum use by
hams.<br>
<br>
Bob Wilson (WA9D)<br>
</body>
</html>