Packet Radio
1 / 20

Packet Radio - PowerPoint PPT Presentation

  • Uploaded on

Packet Radio. For Hamradio. 1st. A Little History. ALOHAnet. A class project at the University of Hawaii The Professor was a ham 70 cm was the band The year was 1971 Successfully demonstrated the world’s 1 st random access network and mailbox. Evolution.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about ' Packet Radio' - carl-james

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Packet Radio




ALittle History


  • A class project at the University of Hawaii

  • The Professor was a ham

  • 70 cm was the band

  • The year was 1971

  • Successfully demonstrated the world’s 1st random access network and mailbox


  • ALOHAnet moved from radio to wires.

  • There were several iterations for improved performance

  • 1973 – Bob Metcalf at Xerox invents ethernet

  • Bob Metcalf opens 3Com and the rest is network history.

What’s important about this?

  • Hamradio was first to demo an important capability

  • Dial-up networking was starting up to allow access to E/N connected networks

  • Modems were being maufactured that allowed inexpensive home opertions

  • Dial-up BBS’s were becoming “common”

  • Hams’ curiosity was again piqued.

So what did the hams do?

  • A handful started to experiment with telephone dial-up modems at about 300 Baud

  • A few invented their own modems using the XR series chips

  • The wired protocol, X.25, was adopted for early packet radio

  • X.25 was extended to AX.25 to handle addressing issues.


  • Early BBS’s were patterned on the dial-ups

  • By the Mid 1980 networks of networks were incorporated into amateur packet radio.

  • Phil Kairn, KA9Q, puts TCP/IP on top of AX.25 to extend network capabilities

  • TAPR created the TAPR-2 TNC.

  • AEA, MFJ, Kantronics, and others started to make and sell affordable TNCs based on TAPR-2

  • And now we are up to date.

The Neo Situation

  • AX.25 has been accepted by the ITU as RX.25

    It’s the same thing, just the name was changed to fit ITU standards

    . 1200 Baud has become a defacto standard

    .RX.25 is now standard with a few TCP/IP BBS’s

    .From it’s peak in the 80’s to early 90’s, amateur packet mainly supports EMCOM and APRS


  • FSK, 170 Hz. shift is used for 1200B

  • Some TNC’s use 200 Hz. shift

  • Sound cards have begun to replace hardware TNC’s

  • There are no backbones left in the area.

  • Connecting through digis is common

  • Packet radio and the Inet have merged

So, you really want to do it?How to do it and what you’ll need

  • You will need:

  • 2 meter radio

  • Computer running a terminal application

  • Either a TNC or sound card. (I recommend a TNC)

  • The usual 2 meter antenna

  • Cables to hook up everything

  • Time to play and a BBS in line-of-sight

What a BBS Needs

  • 2 meter radio

  • Computer

  • Either a TNC or sound card (I recommend a TNC)

  • BBS Software

  • The usual 2 meter antenna

  • Cables to hook up everything

  • Looks just like a home station, however there will be a need for more storage if there is a lot of traffic.

Some basic things to know

  • Almost all TNC’s today can act as a simple BBS.

  • Any station can digipeat if that capability is turned on

  • TNC based BBS’s can not route

  • All packet networks work on a carrier sense, multiple access (CSMA) basis same as ethernet

  • Packet radio uses error correction, APRS does not

part II

  • There are a number of different BBS types; ie, FBB, NET/ROM, RLI, MBL, etc.

  • There is a general commonality in the commands

  • HF packet is painful, but you can try it on 14.104 MHz.

The Club’s situation and BBS

  • Everything was smoked in a lightning strike

  • AARC was running a Phil Kairns based BBS accepting RX.25 and TCP/IP, JNOS.

  • Digipeating was turned on for range extension

  • AARC could do static routing via radio or ethernet and had at least 5 Gbs of data storage.

  • TCP/IP apps FTP, SMTP, and Telnet were acceptable.

  • Everything should be replaced due to age or lightning.


  • Kantronics KPC-3 - $230.

  • Astron RS-20 - $140.

  • Kenwood TM-281A - $150.

  • A cheap netbook - $200.

  • Assorted cables - $50. (est)

  • Total Est. - $770.