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Version V0.0
by
HB9JAQ
JT65-ARQ
is a software program for text messaging using the digital amateur radio modes
JT65 and JT9. While the main purpose of these low speed communication modes
developed by Joe Taylor K1JT is the exchange of predefined and standardized
packets of information JT65-ARQ enables also a comfortable message exchange of
longer free texts. Therefore the exceptional weak signal properties of the JT
modes are available for free text messaging. JT65-ARQ does not implement the
transport layer but uses the functionality already available by the software
WSJT-X by Joe Taylor K1JT which is publicly available as an open source project.
Using build 3777 (Version 1.3) of WSJT-X as a base the author of JT65-ARQ has
implemented some extensions to WSJT-X in order to make the program able to be
remote controlled by a third party software. This way JT65-ARQ can use all the
necessary functionality of WSJT-X without reinventing the wheel. JT65 and JT9
transmit information in packets of a few characters at a time. So JT65-ARQ
splits a text message to be transmitted into a number of packets with a maximum
of 13 characters each and transmits these packets to the receiver where the
packets are reassembled to a complete text message. Every packet has to be
confirmed by the receiving station. If the confirmation is missing the sender
retransmits the packet a defineable number of times. Using this mechanism an
error free transmission of the payload can be achieved down to a S/N ratio of
less than -22 dB.
JT65-ARQ
offers the following functions:
Version |
Modifications |
V0.0 |
First beta release |