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Using the HP Palmtop with Ham Radio

by Phillip Nichols, maccabeus@gatecoms.gatecom.com

About the author: Phillip has been interested in computers since he purchased his first computer, a Commodore Vic-20. He spent his Junior year in High School as a teacher's assistant in his school's first computer class. Since then, he has used his personal, palmtop, and amateur radio skills to help others, spiritually and otherwise.

Recently my notebook PC took a trip to the doctor; maybe it was a vacation since it was gone for almost two months. My computing was done solely on my HP 200LX. It so happens that at about the same time I received my FCC license for Amateur (Ham) Radio. (I had the urge to try Ham Radio, studied from scratch, aced the test, and waited around for the license).

All right! My license came in (KC8DQF)! Now I could "boldly go where no-one has gone before...," or at least where I'd never gone. I immediately wondered if I could tie my Palmtop into the radio for wireless work. I read about something called "Packet-Radio" -- a way of connecting computer systems and networks by means of Ham radio. Then I saw an ad for a "packet modem" that plugs into a computer to convert it to a TNC. A "Terminal Node Controller" is what Ham operators connect to their radio for the digital/analog conversion of the computer data as well as for providing error correction protocol called AX.25.

The packet modem was the BP modem by Tigertronics (1-800-8-BAYPAC). It comes with special communications software and the modem (a small 2-inch-square custom analog/digital modem based on the old Bell-202 standard). The BP draws 9ma of power directly from the serial port of the computer. No external power supply for the modem is needed with a standard PC. The general advice with a Palmtop is to use an AC adapter when connected to a modem. However, I find that the BP modem does not significantly reduce battery life and don't bother with the adapter.

The final piece of hardware in this setup is the actual radio transmitter/receiver (a RadioShack HTX-202 Transceiver). I prefer this radio because it does not allow Wide receive 108-174Mhz. What this means is that it is less bothered by what is called "Intermod" or interference from ghost signals "mixing" with Ham signals. This is important in choice of radios for this type of work. Now the question was: "Can I hook all this up to my HP Palmtop?"

Sure enough! I fiddled around and got it all to work, and then discovered that someone on the web has done the same thing with the exact same equipment (minus the antenna). So now there were at least two of us using the same Palmtop/packet radio combination. Now I could really send and receive "airmail." Although I use this system mostly at home from a desktop PC, the fact that it works with the Palmtop means that I can logon anywhere. Even from inside a shopping mall or at work.

I physically connect my Palmtop to my wireless transceiver using my packet modem. Previously I have loaded the necessary software drivers on the Palmtop so that it can communicate with the modem. I start the Packet radio communications software on my Palmtop and type "connect" followed by the call letters of the person I want to communicate with. It's that simple.

Each packet radio area will probably have many PBBS's (Packet Bulletin Board Systems) running a newer communications protocol known as JNOS. This protocol is similar to an Internet TCP/IP protocol in that it lets you communicate with packet radio addresses that are not in your immediate area.

Once you establish connection, you get a menu just like a normal BBS menu. There are up to 30 commands you can access, so there is a lot you can do depending on what BBS you connect to. As with Internet, Packet BBSs let you "telnet" (link) to other sites in neighboring counties or states. You can even send files by radio, although 1200 bps is a bit slow.

Jason Baack of Maine, the other person I mentioned that uses this setup, told me how he got started.

"I was first introduced to packet radio two years ago on Rainbow Lake in northern Maine (U.S.A.). The total permanent population for the area was listed as four, living in a township called 'T2R11.' There were no roads into the lake, (you had to fly). Three 1.5K generators provided power during the daylight hours, so I was able to use my ancient Packard Bell 286. I got my Ham operators license while I was up there, got a wave antenna and other necessary equipment, and had a blast the rest of the summer connecting to DX nodes, the far reaches of Canada, Nova Scotia, and talking 'keyboard-to-keyboard' to some local (20 miles away)."

As it is now I can hit a packet Bulletin Board Service near me and get mail, topical groups, and telnet to other stations that may otherwise be out of my power range. There is even a World Wide Web/IRC-style conferencing area called CONVers for communication with other "packeteers" around the United States. And finally there are Gateways that tap directly into the Internet to speed things up.

Amateur Radio provides you with the opportunity to experiment and challenge your own personal limits. In addition, it lets you give something back to your community. I definitely stretched my Palmtop's capabilities, but there's more room to grow. With my HP Palmtop I can run satellite tracking programs to locate Amateur radio relay satellites in "real time" using REAL95.ZIP . I have another TSR program I run while on packet that can help locate and calculate the distance between myself and the ham on the other end (GRID.ZIP ). I have modified a Palmtop-database for keeping a log of my contacts (ARS-LOG.ZIP ). You can investigate ham-related topics by contacting a SIMTEL site on the Internet. Most have an amateur-radio and packet directory listing topics of interest. One such SIMTEL site containing about 100 topical directories is: http://oak.oakland.edu/simtel.net/msdos/index-msdos.html

Another non-SIMTEL, but more ham-specific site is: http://www.cdrom.com/pub/hamradio/oak

The more I look, the more people I find using their Palmtop with radio. We hope to "QSO with you on 2meters (144-148Mhz)" sometime, or else exchange some packet e-mail! So how about getting your license? It's now easier than ever to get started, you don't even need to learn Morse-code to begin (but you'll earn more respect if you do). You have nothing to lose, and world of ham operators to gain.

For more information visit Jason's web site at: http://www.umecut.maine.edu/~baack
or Ham-Radio Online at http://www.hamradio-online.com

Ham operators designed their own "Network" of computers back in the late 70s. The Canadian Department of Commerce legalized Packet Radio by ham operators in 1978. Then the TAPR '80 (Tucson Amateur Packet Radio corporation ) began developing radio communication protocols. 1981 TAPR decided to use a version of the computer industries x.25 communications protocol, calling it AX.25 ("A" for amateur radio). Packet radio communications started with a few people who could afford computers and to modify Bell-202 modems with the TAPR chip protocol.

Soon computer prices fell and Terminal Node Controller kits were becoming more available. Radio networks were being set up much like a unix "on/off LAN" and businesses "constant-on LAN." An example of an "on/off LAN" is an Internet web browser, that is not actually connected to the web site all the time, but intermittently connects to ("pings") the web site for information. A computer bulletin board system like CompuServe is an example of a "constant-on LAN" because it is always connected to the net and to other nodes in its system.

Pricing and Contact Information for products mentioned in this article: All prices are manufacturer's suggested retail price. It may be possible to purchase the product for less at third-party vendors.

BP Modems
Model 2 -- $49.95
Model 2M -- $69.95
Contact: Tigertronics, Inc, P.O. Box 5210, Grants Pass, OR 97527, U.S.A.; Phone: 800-8Baypac or 541-474-6700; Fax 541-474-6703; http://www.tigertronics.com

Shareware/freeware mentioned in this article

• HAMRADIO.ZIP -- available on the July/August 1996 issue of the HP Palmtop Paper ON DISK and includes the following three pieces of software:
  1. REAL95.ZIP -- Executable satellite tracker intended for use on the Palmtop. Freeware. Also available on the Internet at : ftp://eddie.mit.edu/pub/951x/NEW/
  2. GRID.ZIP -- Amateur radio executable and documentation files. Shareware. Contact: David Eanes, 4866 Drusilla Lane, Baton Rouge, LA 70809,U.S.A.
  3. ARS-LOG.ZIP -- Database template for the Palmtop for logging radio contacts. Freeware.
• GEOCLK40.zip -- Graphical display of sun/moon for grey line propagation
• GEOMNO44.zip -- converts EGA version to CGA, customize cities to display contact points by entering lat/long of gridsquares and label with state name or grid square worked.

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