Friday, September 19, 2008

Where's David?


Been a while since I posted. Most of the summer was spent doing various projects; some for pay and some for fun. One of my new interests is APRS - Automated Packet Reporting System. It started when a ham friend of mine decided to hike the John Muir Trail and wanted me to keep in touch with him and his girlfriend as they hiked. He carried a Kenwood TH-D7A(G) APRS handheld; so I decided that I would set up APRS to track him.

In the process of doing this I learned a lot about APRS and the mechanics of routing packets through RF. I set up an "I-Gate" which is a system that passes received RF packets into the APRS servers via the Internet. Turns out this was quite useful to some local hams that carried Kenwood TH-D7A(G) APRS handhelds which could not normally reach the mountain-top APRS repeaters aka "digipeaters". So now my station's running 24/7; not great for keeping the electric bill small but I guess that's why I have a 3 KW solar PV array on my roof, yeah?

In exploring APRS I learned that when it comes to digipeaters "more" is not necessarily equated to "better". RF packet is about passing packets to the target (or targets) with little (or ideally no) redundancy. For the most part we enjoy a great VHF environment here in the Bay Area; the Silicon Valley is ringed by mountain ranges which provide line-of-sight at nearly any time to at least one of the wide-area digipeaters. Any additional digipeaters are redundant and therefore create extra packet traffic. (The exception to this is of course low-level/low-power "fill-in digipeaters" designed to serve small pocket valleys, urban canyons, etc.) With a dense population and a lot of hams using APRS it's a constant battle to keep the 144.390 MHz APRS channel from becoming too crowded. I-Gates don't contribute to the crowding problem; that is if they're set up as receive-only I-Gates.

I'm having a good time with APRS; besides just being able to track locations I've also been exploring how it can be used for text communication; I had a nice QSO with YB2TJV in Indonesia recently. It's also proving useful to study VHF propogation in the area. I have no idea why my callsign was used by OH7LZB as an example in his blog post on the new I-Gate coverage function on aprs.fi; but I was flattered anyway!

I'll be hosting a forum on APRS at Pacificon 2008 which runs from October 17th - 19th in San Bruno, CA. My forum is scheduled for 8:00am Sunday the 19th; if you're in town please do come by and say hi!

Thursday, May 29, 2008

Tech Note: Radio Shack Pro-2018 Scanner


I recently purchased a cheap radio scanner to replace my venerable I recently purchased a cheap radio scanner to replace my venerable Electra Bearcat 250. I bought a Radio Shack Pro-2018 (catalog # 20-424). Reading through the Radio Shack website a few days ago I was amazed to find that they were selling the programming cable for my scanner for 97 cents!? The cable (catalog # 20-429) is being discontinued, apparently. I found a store which had one and picked it up.

Radio Shack also offers a free programming software package. It is quite frankly one of the lamest applications I've ever seen; an absolutely horrid GUI and it would only import from DBase III format (.dbf) files. A quick Google search revealed an open-source scanner loader application "ProLink" which looked promising. It doesn't specifically state support for the Pro-2018 but it does support the Pro-2017 and the Pro-79 which are (from a serial port interface perspective) the same.

The nice thing about ProLink is that it can open text and CSV files, so creating a frequency list from copied text is fairly easy. I used Excel, and copied a lot of data from RadioReference.com and K6SCC's SCCFreqs.info page. Caveat: Apparently most of these low-end scanners don't have a download function. So don't expect to use ProLink to download the painstakingly-created frequencies you may have already on your scanner.

I ran into two small but annoying glitches which I'd like to share. One glitch was that when I initially tried to open my CSV in ProLink the application would lock up and require a process-kill. I knew the application could open CSV files because it successfully opened a sample file included with the application install. Examining the good vs the bad CSV revealed that Excel did not maintain all of the commas and quotation-marks around text which apparently ProLink expects. So I had to open the CSV in a text editor and manually reformat the file. Thank you, Bill Gates.

The second glitch was in trying to get the serial interface to work. Turns out the I needed to reconfigure my USB-serial dongle for the following config: 4800-8-N-2 (4800 bps, 8 data bits, Parity=None, 2 Stop bits) and Flow control set to "None".

Once I did this the data file loaded into the scanner no problem. I'm not sure I saved any time doing it this way, but at least now I know that I have a soft copy of my frequency list and should I need to make any changes I can do this in the file and then reprogram the scanner.

Tuesday, May 6, 2008

Wireless at Maker Faire 2008


Last weekend my wife went on a short trip with some friends, leaving me home to try my hand at single fatherhood. Still, I managed to get away from my "Mr. Mom Weekend" for a few hours on Friday and Saturday nights (paid a babysitter on Friday, and cajoled my mother-in-law into service on Saturday). On Friday I attended the PAARA amateur radio club meeting in Menlo Park, and on Saturday I drove up to the Maker Faire in San Mateo. The role of wireless technology at the Maker Faire was very evident, but not in the way you might expect. For the uninitiated; the Maker Faire is a combination of Burning Man + science fair + flea market. People come to show off their contraptions and creations; robots, alternative fuel vehicles, lots of stuff which uses embedded controllers, and (especially after the sun went down on Saturday) enough fire and explosions to satisfy even the most ardent pyromaniac. The highlights for me were:
The contrasts at the Maker Faire are numerous and glaring. The parking lot is filled with hybrid cars, and the usual "Impeach Bush"/"Obama 2008" bumper-sticker polemic you expect to find in the SF Bay Area. So you'd think the Maker Faire would be focused heavily on eco-friendly and minimal carbon footprint exhibits. And yes, there were a huge number of exhibits showing off renewable energy and transportation technology; solar, wind, algae-fuel, bio-diesel, electric motorcycles, pluggable hybrids, etc. But after sunset there were also many combustion exhibits and shows using propane, kerosene, lamp oil, etc. The smell of incompletely burned hydrocarbon was everywhere, as tongues of smoke curled up against the deepening sunset in the chilly evening air. How to reconcile this? I don't know that I can. Is the Maker Faire a neutral zone in the global warming debate, a sort of United Nations of carbon consumption? Or is this yet another example of hippie hypocrisy? Best if we leave that one to the philosophers.

If you're still reading, you might be wondering how this all relates to wireless. It does, and thanks for sticking with me as I get around to that. Wireless technology of all types was very evident and widely used at the Maker Faire, but the operating word here is "used". There were no exhibits (that I saw) which showed off anything related to innovation in the wireless space. There were a ton of people using Wi-Fi, Bluetooth, proprietary ISM data-link radios, radio-controlled servos, etc. Wireless was everywhere, but in all cases it was "user wireless"; projects created with off-the-shelf modules and in some cases chipsets. Wireless is a tool to complete projects, not the project in and of itself. I find that this echoes a growing trend I've observed at the WCA and in the wireless industry as a whole: Put plainly, wireless technology is becoming a commodity.

Some of the hams from PAARA set up an amateur radio special-event station to make 20m and 2m/70cm contacts from the Maker Faire. I never found this exhibit, but a few people on the N6NFI repeater say the station had to contend with some bad RFI; which I can imagine given that a giant Tesla generator was operating nearby. I'm quite sure that most of the Maker Faire was essentially a gigantic FCC Part 15 violation.

It's unfortunate that the hams did not have a bigger role at Maker, because amateur radio has its roots in innovation and home-brewed technology; ham radio is a great-great-granduncle of the Maker movement and should rightfully hold a place of honor and respect in the Maker community. I think that the problem is that a lot of amateur radio has become consumerized and is now ironically an example of the "culture of learned helplessness"; ironic because the technology consumerism which is the fastest growing segment of amateur radio (i.e. people who chose to buy versus make) is at odds with the hacking/creation/innovation core elements of the Maker movement.

The amateur radio community still certainly has a lot to say about innovation and technology; the huge number of hamfests, tech days, field days, DXpeditions, etc is evidence of this. The problem seems to be that amateur radio events have become somewhat insular; we're doing events for ourselves, and not reaching out as much as we should to non-hams. By way of example; this month's AM-TECH Day is on May 10th. Past proof shows that it will be popular, or at least popular with hams. Wouldn't it have been better to push AM-TECH up a week and hold it at the Maker Faire? How many Makers could we have licensed if we'd held AM-TECH and a VE test session a week earlier at the Maker Faire?

I also think that we need to seriously rethink our approach to new technologies. Hams are spending way too much energy on "maintaining the tradition" in modes of operation such as CW and voice, and not exploring how amateur radio might benefit from integration with other technology. I think radio amateurs still have a lot to offer the wider technical community, but we need to reach out and open our doors. This means far less worrying about nurturing traditions and whining about the evils of no-code HF, and a lot more mold-breaking. The concept of the Maker Faire and amateur radio is to hack, to repurpose, to change forms and function. We can learn a lot from the Maker community, and they from us. How do we make this happen?