[unoti]

Go get your HAM radio license. It's a great way to get in touch with your hacker roots, and connect with interesting like-minded people. The most important resource when any kind of trouble breaks out is friends, and HAM radio people are great, smart, resourceful people to know.

When you're studying for your license, use my HAM Radio study guide for Android (https://market.android.com/details?id=com.tango11.hamstudy&#...). It's free and there are no ads; just something I did to give back to the community.

[burgerbrain]

Somebody with more experience should correct me here, but I'm under the impression that the penalties for illegal transmission (for example I believe, encrypted communications) are harsher for people with HAM licenses.

Something to consider, if that is accurate.

[TheAmazingIdiot]

Its usually intentional, malicious transmission the FCC cares about. There was some lid in Texas that kept on playing laugh tracks and howlers over peoples' FM communications. In FM, the strongest power transmitter will 'capture' the receivers in range unlike AM, where you hear a smear of all audio tracks.

The guy was eventually caught. His punishment was $20K and the loss of his license.

However, in all honesty, an encrypted communication can be claimed that you are working with digital modes with different compression schemes. The only real requirement here is to have a call sign in the clear in a common digital mode (CW preferred). Just dont be stupid and do a dump of a GPG encrypted block down the xmit.

For example, I regularly run channel 12 on my home wifi gear (european firmware). On my router, I have a sticker that states my callsign and EXPERIMENTAL. It's now allowed under part 97 tentatively. I also, out of respect, went to the 2 local HAM groups and stated what I was doing and where. If there's interference, I can change it.

[gonzo]

I have no idea why you think this is a good idea.

Go look at the ACR specs for the chipset in your AP, and then realize that they're talking about the 'spacing'(for example) between ch 1 (centered at 2412MHz), 6 (2437MHz) & 11 (2462MHz) in the 2.4GHz band. Note that the center frequencies are 25MHz apart. In DSSS (1 or 2Mbps) or CCK (5.5 or 11Mbps) your radio has a signal bandwidth (or frequency occupation) of 22 MHz. Using OFDM modulation, the signal bandwidth is 20MHz.

Radios do not have an exact edge to their channel, and energy spreads beyond the edges of the channel boundaries. However, the overall energy level drops as the signal spreads farther from the center of the channel. The 802.11b standard defines the required limits for the energy outside the channel boundaries (+/- 11 MHz), also known as the spectral mask.

At 11 MHz from the center of the channel, the energy must be 30 dB lower than the maximum signal level, and at 22 MHz away, the energy must be 50 dB below the maximum level. As you move farther from the center of the channel, the energy continues to decrease but is still present, providing some interference on several more channels.

Ch12 is centered at 2467MHz. 11MHz up is 2478MHz. The US ISM band ends at 2485Mhz. In theory you don't need to be a HAM running under part 97 to transmit here, BUT remember that you're probably transmitting at 100mW (20dBm), so your radio's design is probably transmitting 50dBm into the edge of the band.

MOREOVER, the HAM band in-question is 2390-2450 MHz, so you're operating illegally when you're transmitting WiFi on ch12 (centered at 2467MHz!)

[TheAmazingIdiot]

Comments like yours is why I didn't post my callsign.

We've discussed what my proposal was with the 2 local ham groups. One person works for the FCC and finds non-compliant stations. From what he indicated, as long as I put "EXPERIMENTAL" on the device, and watch for interference (iow: be a good amateur operator), I can do this.

I've passed their kind requests, along with publishing what I am doing and with what wattage I am transmitting. I am also monitoring my emissions as I usually do when operating.

I'd also like to remind you that an evil device called a microwave oven transmits more as static on 2.4GHz broadband than my narrowband wifi.

[gonzo]

You can think what you like, of course. You're still intentionally generating OOB emissions. HAMs like you are actually dangerous to the hobby.

A U.S. Federal Standard exists (and is used in most of the world), that limits the amount of microwaves that can leak from an oven throughout its lifetime to 5 milliwatts of microwave radiation per square centimeter at approximately 5 cm (2 in) from the surface of the oven after sale. (at manufacture, the limit is 1 mW/cm2 at 5 cm.)

US Dept. of HEW, FDA, Bureau of Radiological Health, “Regulations and Enforcement of Radiation Control for Health and Safety Act of 1968” paragraph 1030.10; Microwave Ovens pp 36-37 PHEW Publication No. (FDA) 75- 8003, July 1974

Now, what's the EIRP of your setup again? Assuming a 50mW (17dBm) radio and 2.2dBi 'short dipole' antennas, and maybe 1dBm of loss in the connectors/coax, you're at 18.2dBm EIRP at the surface of the antenna. Call it 65mW for grins.

At 2450MHz, you'll be down -14.2dB 5cm away. 18.2-14.2 = 4dBm, so 2.5dmW @ 5cm. You're lower than a worst-case microwave (but higher than anything that's allowed to be sold!), unless you fit high-gain antennas or high-power radios.

KD5FGA, btw. (also www.netgate.com)

[ge0rg]

> It's free and there are no ads; just something I did to give back to the community.

This is the spirit that made HAM Radio a success in the first place. I wish more of it would be still present.

Out of the same motivation, I have developed an open source APRS app for Android (http://aprsdroid.org/) written in Scala. It is available (for a fee) on the Market as well, but you can download the APK freely from the home page. :)

[dlsspy]

aprsdroid is pretty nice. I've used it to test messaging when I'm RF only, and I've gated messages to the internet from my phone using the speaker and an HT. Glad to have it. :)

I didn't know it was written in scala, though. That adds extra awesome to it.

[Natsu]

I still have an old Tech+ license but I became inactive when I moved away to college and had no rig, no time and no ham friends at ASU. It would be nice to do more with it someday.