Choosing Radios and TNCs for Winlink
2000 Packet
The best choice in a radio for use on VHF/UHF packet
is one with a data port. Ideally, it is nice to have the receive and transmit
audio within the same connector. If no data port, then: Is the receive audio
available at the microphone connector?
If the receive audio exists in either of those places, the level is
fixed and is not affected by the volume control or the squelch control. But
what this means is that the TNC must have DCD capability meaning it can operate
with open squelch. If fixed receive audio is not available, then the only
choice is to take it from the speaker or the speaker jack. This means adjusting
the volume control for the proper level.
If you don't have communications or serial port on
your computer, you will need to obtain a USB-to-Serial adapter. Most will work
but I guess it's sort of like buyer beware until proven satisfactory for the
application. You might need to load some software for the adapter to work
properly.
A TNC is needed for VHF packet. To go beyond Airmail,
you will need the AGW Packet Engine. It is a software engine that controls many
different types of TNCs. If you don't have a TNC, and need to purchase one, then install the freeware
AGWPE and take a look at the list of TNCs it supports. The list within AGWPE is
a good way to learn what to look for and to buy. AGWPE supports soundcard
operation at 1200 baud. I use it on my notebook computer.
The TNC connects to the computer's serial port or the
USB-to-Serial adapter with a RS-232 serial cable. Make sure you buy the correct
gender for each end. Most computer serial ports and USB-to-Serial adapters use
a DB-9 Male connector. Buy a DB-9 Female to mate with it; do the same check on
the TNC and buy the opposite gender to mate with it.
An interface cable is needed between the TNC and the
radio. Most are easy enough to make yourself. You need to know is what each
connector pin is for. Manufactured cables are available from multiple sources
on the Internet.
Airmail works work only certain TNCs. The list is in
the setup menu within Airmail. And, sometimes Airmail can be tricked to make a
TNC work by calling it by a different model number by the same manufacturer
found in the supported list
Some of the older TNCs might need a firmware upgrade
to run packet for Winlink2000. Typically, the upgrade is in the range of $50 to
$75. All of the older TNCs will run 1200 baud packet. The newer ones might be
able to operate at 9600 baud. But be careful, unless specially designed for
9600 baud, only some VHF/UHF FM radios meant for voice operation can operate at
that speed. Know what you have! Beware
of a VHF/UHF transceiver with a built-in TASCO TNC - it will not work with
Winlink2000 Email. The TASCO TNC is designed for APRS (automatic position
reporting system) use. These transceivers need to use an external TNC for
Winlink2000.