Packet Radio

The Springhill Amateur Radio Club is in the process of adding a packet communications “digipeater” (digital repeater) to allow local hams to connect to the worldwide packet network. The digipeater will be located on a 400 foot tower in Springhill, LA and will extend the range of home or mobile packet stations. It will have the capability to relay your packet messages  into region-wide, nation-wide and world-wide packet networks to send messages long distances without the internet.

Packet radio is a digital radio communications mode. It is used to send short messages such as emails, texts and small files over ham radio without using the internet or phone systems. The primary goal is to have a world-wide emergency backup packet network that will continue to function should the normal internet or phone systems go down and there is no phone, email or text capability via normal channels. Such situations have happened during the recent California fires, hurricanes, and other regional disasters where the enormous amount of fixed infrastructure that supports the internet and cell phones was disrupted.

A packet station consists of a simple computer (laptop), a cheap VHF mobile or handheld radio and a small interface device between the radio and computer called a TNC (Terminal Node Controller).  Emails, texts or small files are sent from the computer through the TNC to the radio and out the antenna. The message makes a couple of hops through relay stations called “digipeaters” until it gets to an offline mail server / bulletin board.  The mail server / bulletin board acts as an electronic post office where you pick up your mail. It is very similar to how you pick up your mail from Yahoo or Gmail but there is no internet involved. For packet, the email is usually on software called Winlink which is free and installed on the computer.

Any radio with a TNC can act as a digipeater to link distant stations with each other through “as needed” networks. This makes packet radio especially useful for emergency communications such as wildfires or hurricanes. Mobile packet radio stations can enter the area and relay messages out. They also automatically transmit their location, and check in periodically with the network to show that they are still operating and available to pass emergency messages if needed.

Packet is similar to emergency voice communications except it allow messages and files to be sent and left in mailboxes if the destination station is not available at the time the call is made. Typed messages are also more accurate than relayed voice messages as the exact words sent are the exact words received.

The digipeater frequency is expected to be 145.01 MHz at 1200 baud signal rate.

Links to more information on Packet Radio are below:

http://www.choisser.com/packet/