On Aug 1, 2005, at 8:33 AM, Frank Keeney wrote:
For a PTP link, the FCC says you can run 30dBm (1W) tx power into
6dBi of antenna gain, and then reduce the tx power 1dBm for every
3dBi of additional antenna gain.
They ran their link under FCC Part 97 rules.
While Part 97 would give them the EIRP relief that you seem to seek
to justify, Part 97 also says "do not use more tx power than you need
to close the link" (not those exact words, but thats the jist of it),
and they're clearly running more than they need if they're 30dBm above
the sensitivity limit.
Further (and worse), Part 97 will *NOT* relieve them of transmitting
(spurious) signals in the restricted bands (well out of the Amateur
bands
allowed under Part 97). This is still illegal, and any licensed HAM
would know better. Perhaps you will:
a) explain how they knocked the side lobes down so they didn't have
unwanted emissions outside the band. Your answer here very likely
has the word "filter" in it, but then I'll just ask you for the
mfg/model # of same, so I can verify its claimed performance.
b) explain how they transmitted their HAM call sign (perhaps they set
the ESSID to it, but this wouldn't fulfill the requirements of Part 97)
c) send along the call sign(s) used during this experiment, so the
FCC can pull their tickets.
They deemed it "reliable" since it their applications, ssh to each
other's
Linux laptop, VNC etc. were up and running uninterrupted for
several hours
while they waited for the judges to arrive.
They deemed it reliable because they wanted to. Did they put any
load on the network? Many people will misinterpret the results,
and clamor for 125 mile links with no other requirements than "line
of sight" and "big ears". For the reasons I've shown, and others,
while you might be able to "show" this in a "demo", its both illegal,
and it doesn't (nee: can't) work correctly.
Netgate also gets requests to support these types of events with the
ever-present justification, "free advertising". We always turn them
down, because I don't want my name sullied with activities in the
802.11 space that are of questionable legality.
Jim
p.s. Vivato, when it was Mabuhay, attached an ordinary Lucent PCMCIA
card to a 12' dish (with the appropriate cavity filter in-place) and
got bits to/from someone's laptop (also with a Lucent card) who was
sitting on the chairlift some 12 miles away. I mention this because,
other than aiming the dishes, the Shootout isn't really "new", and I
happen to know that cavity filters exist that will do the job (as
well as what they cost.)
