Amateur Radio Packet Over 802.11 Cards

Skuld-Chan writes: "I stumbled across this the other day -- basically discusses modifying common 802.11 boards for amateur radio bands (or Part 97 rules). Under Part 97 there is a 100 watt limit and no gain limit (unlike the 6 db gain limit on Part 15). I thought it was interesting :)." Consult your friendly branch of the FCC :) Note that this is just one of several interesting projects from this site.

Comments

Would https be a violation?

[iamroot]

The FCC laws state that you may not use ciphers to obscure the meaning of your transmissions. What if someone was using https, ssh, or another encrypted protocol over this? Would that be a violation? Its not really clear what that part of the amateur radio laws mean. If that would be a violation, then I'd have to wonder about the practicality of this. Aside from an alternative to TNCs, there might be problems with actually setting up a network, aside from the fact that anyone on it would need licenses.

Re:If I had speakers that handled it..

[Chanc_Gorkon]

Music and amatuer radio doesn't mix (not sure if the data would be though like if it would be a MP3....). The only station allowed to broadcast music on the amatuer bands is the space shuttle.

Re:Before everyone jumps on the bandwagon...

[Bishop]

There are two important restrictions that should be concidered. In North America you may not transmit in code. i.e you can't use crypto. The second restriction is a tough judgement call: you can't use the amature bands for commercial use. This may restrict you from shopping on line over an amature band WAN.

There are some other restrictions, but these are probably the two big ones that will affect the /. crowd.

Re:interference

[Perdo]

A microwave oven has a "white" high power amplifier inside. It tries to transmit as close to 2.4 Ghz as possible, as this is the resonate frequency of water molecules. The actuality is they produce a more "white" RF, like a white lightbulb produces a broad spectrum of light compared to a laser. Any saw filter placed on such a transmitter, would get very hot indeed, and would waste the energy that could be used to heat the food. The filter would get hot instead of the food.

Since the RF is white, there is no way to design a feedhorn or antenna to properly radiate the power. High VSWR would kill the transmitter in a very short period of time. Food in the microwave acts like a dummy load. It absorbs the RF, so little gets reflected back into the transmitter. VSWR as low as 15% of total power out of a klystron will make it explode in just a few seconds. The electrons "piling up" forces the klystron to act like a capacitor, and the electron gun will arc with the collector, causing the glass vacume chamber surrounded by rare earth magnets to implode with a force compounded by the high voltage being applied to it.

Suffice to say, a klystron out of tune or improperly capacitance match with it's antenna goes like a grenade.

Make sure you disable the power supply safety interlocks and bypass the fuses in addition to cutting a hole in the door of the microwave to achieve this effect.