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1998 ARRL and TAPR Digital Communications Conference

17th.jpeg September 25-27, 1998
Chicago, Illinois

Yes, another highly successful Digital Communications Conference! Special thanks go out to the workers at CAPRA for hosting locally and to PRUG for being our first ever international co-host. Also, a very special thanks to Dale Hatfield, W0IFO, for attending and giving the keynote address on Saturday morning. Steve Stroh, N8GNJ, and Tina Stroh did an excellent job in working the arrangements with the hotel in Chicago once it was selected.

Next year's DCC will be hosted in Phoenix, AZ.

See pictures from the conference.

Proceedings are available.


APRS National Symposium
    The conference started Friday afternoon with the second annual APRS National Symposium moderated by Steve Dimse, K4HG. The symposium was full of talks and projects. Steve had his computer set up for a live web cam.

    During the symposium, two mystery hardware projects were discussed. The first was a Kenwood Prototype Data communicator HT. This was a sneak preview provided by Kenwood to all those attending the DCC. By the time this PSR article is published, the HT should be available. It is a full function dual band 5 watt HT with tons of APRS related features:

    • 1200 / 9600 baud TNC built in
    • GPS interface built in
    • APRS displays built in
    • APRS Messaging (with Igates, it's like a nationwide 2-way pager)
    • Receives all APRS packets
    • APRS Mic-Encoder built-in
    • APRS/GPS Single Port Mode built-in
    • DX Cluster spots built-in

    While the HT does not display maps, it does display range and bearing to all stations (40 max). It also displays their ICON, Gridsquare, course and speed, Power, Antenna Height, antenna gain and directivity. It also displays Wind, Temp and Rain for all WX stations. If a graphics GPS is plugged in, then the GPS will show all stations as way points on its maps. With only the HT and a GPS with graphic display, you can do EVERYTHING in APRS (no laptop needed).

    Bob Bruninga, WB4APR, demos the new Kenwood APRS HT. In this photo, Bob is displaying a image of Mel Whitten, K0PFX, who is on the front row using the radio and Kenwood's portable camera combination.

    The second mystery hardware device is called the Pic Encoder, or Pic-E. This is discussed in detail in this issue of the PSR. It is designed as an enabling device, to allow others to have access to the joys of Pic programming for APRS. The hardware includes the modem and a flash-programmable PIC chip, with the associated circuitry. The unit is not designed as a Mic-E replacement. However, with software that will be available, you can use it as a weather encoder (plug into Peet Bros. or Radio Shack and radio...no TNC), a GPS encoder (similar to Mic-E), DGPS transmitter, etc. The real purpose, though, is to see what software others will come up with. This is a very easy thing to do; code modules for the AX-25 routines will be available.

    Steve Bible, N7HPR, holding up the TAPR PIC-E project prototype.

Friday RF Seminar

    Late Friday afternoon, a half-day seminar titled "Infrastructureless Technologies in Amateur Radio," presented by Don Lemke, WB9MJN, dealt with the pros and cons of DDMA (directivity division multiple access, a proposed infrastructureless technique) versus hubbed (cellular style) and other infrastructure dependent techniques. The technical seminar was very well attended and comments from the participants indicated that Don did a great job! The audio from his seminar is on the web page for those that couldn't attend.

    Don Lemke, WB9MJN, holding up one of his designed patch antennas for 1.2G.

PRUG Meeting

    Friday night saw the first ever DCC social, which was sponsored by PRUG. After the social, PRUG presented a series of technical papers highlighting their current development. The papers focused on the prototype direct-sequence radio operating in the 2.4 GHz band (there are slight differences in frequencies between the US and Japan in this band) which PRUG has designed. This prototype appears to be very well designed from an experimentation point of view.

    One of the PRUG members setting up the software for the PRUG SS Radio project.

    As an overview of their project, all of the radio protocol as well as future planned software-executed forward-error-correction (FEC) is performed on a workstation. This workstation in-turn is attached via 10-base-T Ethernet cable to a Z80 module (and Ethernet NIC card) located with the radio. The advantage is that the long run of cable up the tower is 10-base-T cable, and the 2.4 GHz coax cable is kept to about 12 inches in length. This Z80 processor performs very limited functionality. It removes a temporary header used to send packets from the workstation to the Z80 (based on UDP/IP) and transmits the remainder of the frame on the radio. It performs the complementary function in the received direction.

    The key advantage of this unusual encapsulation method is that all of the software that defines the network, the media access (MAC) protocols, the FEC codes, etc. resides within a single UDP process on the workstation (which can as easily be a PC). This means that experimentation with different MAC protocols, new routing protocols, etc. is easily accomplished and simple to develop. PRUG is cooperating with the Tokyo Institute of Technology to experiment with, and develop new protocols for packet radio using this technology. It's well suited for a university program because the researcher can spend most of the time focusing on the network aspects, and much less so on real-time issues, software integration issues, etc. This makes it possible for a graduate student to complete a project in one or two semesters with the PRUG hardware. We will look forward to reading the papers published by these researchers on their spread-spectrum, network, MAC, and routing experiments at future DCCs, hopefully! It's a great example of how amateur radio can provide a foundation for and contribute to important technical work.

    The current raw data rate is about 800 kilobits per second and the spreading code is an 11-bit Barker sequence. All radios on the channel utilize the same spreading sequence, so collisions and multicasting are possible. Thus, the radio appears much like one channel in today's packet network except that the data rate is much higher. The channel access protocols are similar. PRUG presented a paper on the use of improved channel access protocols. They analyzed the theoretical throughput of a channel under CSMA/CD (current packet protocol) and MACA protocols (MACA was described by Phil Karn, KA9Q, in a 1991 DCC paper).

    The social and PRUG session were a huge success!


Sunday Technical Seminar

Conference Photos

Steve Dimse, K4HG, Keith Sproul, WU2Z, and David Chesser KA9NHL during the APRS National Symposium on Friday.

Byon Garrrabrant, N6BG, speaking on the TAPR PIC-E during the APRS National Symposium.

Dale Hatfield, W0IFO, Chief of the FCC's Office of Engineering and Technology giving the keynote talk on Saturday morning.

Steve Dimse, K4HG, looking into his laptop camera. The camera was displaying images of the meeting live over the internet. Steve coordinated the APRS National Symposium again this year. Thanks Steve!

Dorothy Jones, KA5DWR, manning the registration table and TAPR booth.

Tim Shepard, KD1KY, presenting his MIT dissertation during the Sunday technical seminar.

Bob Bruninga, WB4APR, demos the new Kenwood APRS HT. In this photo, Bob is displaying a image of Mel Whitten, K0PFX, who is on the front row using the radio and Kenwood's portable camera combination.

Bob Bruninga, WB4APR, outside the hotel making a MicroSat contact using the new Kenwood HT.

Steve Stroh's, N8GNJ, daughter.

Tom McDerrmott, N5EG, and John Koster, W9DDD, in the hospitality room chatting. Tom is currently President of TPRS and working on the TAPR FHSS project. John is involved in several TAPR project and heading up the flashcard project.

Steve Bible, N7HPR, holding up the TAPR PIC-E project prototype.

Byon Garrabrant, N6BG, Steve Bible, N7HPR, and John Hansen, W2FS, caught in the hallway discussing project related issues. The DCC is one of the few times each year that we can all get together face-to-face and discuss projects.

Ev Tupius, W2EV, presenting his paper on PropNet.

One of the PRUG members setting up the software for the PRUG SS Radio project.

A closer phot of the PRUG SS Radio project.

The TAPR Board meeting on Friday. From left to right: Steve Stroh, N8GNJ (sec), Bob Hansen, N2GDE (Psr Editor), John Koster, W9DDD (Board member), John Ackmermann, N8UR (VP), Doug McKinney, KC3RL (board member), Barry McLarnon, VE3JF (board member), Byon Garrabrant, N6BG (visitor), Dewayne Hendricks, WA8DZP, (FCC Regulatory chair), Steve Dimse, K4HG, (APRS QSY Liasion), Mel Whitten, K0PFX, (Board member), Steve Bible, N7HPR (board member). Greg Jones, WD5IVD, Pres, behind the camera :-)

Lyle Johnson, WA7GXD, presenting during the Sunday technical Seminar. Lyle presented a detailed overview of the RUDAK hardware to fly on P3D and how we can start building equipment for it.

Bob Bruninga, WB4APR, playing with his new Kenwood HT.

Don Lemke, WB9MJN, speaking during his technical seminar on Friday. Don gave one of our best ever Friday technical talks.

Don's audience on Friday.

Don Lemke, WB9MJN, holding up one of his designed patch antennas for 1.2G.

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