Hi all,
JT65 is a very different mode from more conventional "keyboard" modes.
It is designed for EME operation with very weak signals, and to allow
for just the bare minimum amount of information that defines a contact
to be exchanged. This leads to some quirks in its operation, which I
will do my best to explain below (I'm hardly an expert on this -- only
been trying my hand at it for a few days!).
This message got a bit longer than I had wanted it to be, so here's a
quick summary of the points (if you don't follow these, many stations
will not be able to work you!):
- Always keep your clock synchronized, to one second or better accuracy
- Always click the "Auto is OFF" button to make it so "Auto is ON".
Those who are interested in why, read on...
The software has a notion of timeslots (as in EME operation). One
station TXes, beginning at the start of a minute, for 48 seconds, then
goes to RX for the remaining 12 seconds. The other station calls back
at the start of the next minute, for 48 seconds, while the first
station RXes for that full minute. This is the standard that stations
follow -- if you don't conform to it, they will probably not be able
to decode you.
Thankfully, the software will enforce this timing for you if you press
the "Auto is OFF" button. The button will then change to "Auto is ON"
and will also be highlighted in red. Also tied in with this
functionality is the "Tx First" checkbox: if checked, your TX slot
will be the even minutes of the hour ("first" meaning "first minute of
the hour"). If unchecked, your TX slot will be (you guessed it) the
odd minutes of the hour. Obviously, one should pick the opposite of
the station they are trying to work :) While "Auto is ON" you will
always TX in your TX period -- so when you are done, make sure to turn
it off, hi.
Whether "auto" is on or off, the software will automatically attempt a
decode at 52 seconds into the minute. If by the time you've decoded
you're already into your TX cycle, just press the appropriate "TxN"
button on the far right, where N is the number of the message you want
(you'll see). If you ever need a quick reference on which is the
appropriate message to send, just hit F5 (or menu item "Help -> What
message to send?").
Also note that decoding isn't an instantaneous procedure: pressing
"Decode" while you are less than 52 seconds into the minute will
attempt to decode last minute's tones again. One must wait for the
end of the transmission cycle to get the latest decode.
Hope this helps!
best & 73,
-chris N2YYZ
