One more post about Unshift On Space (USOS) and then I'll shut up, I
promise! :-)
USOS is not the easiest concept to understand. Here's another way of
thinking about it:
The transmitting station and the receiving station must always be
synchronized regarding LTRS case and FIGS case. When signals are strong
this is no problem, but when sigs are weak or covered by QRM/QRN/QSB
often the synchronization is lost. This is how we get those TOOAPPQAPPQ
messages.
Think of the space character as a "synchronizer". With USOS ON (the
default in most TNC's), every time a space character is sent, the
transmitter and receiver are BOTH re-synchronized automatically. This
happens with EVERY space character, not just in the exchange.
For example, when you send 599-001-001, the synchronizing is done only
once - at the start of the transmission, just before the "5". On the
other hand, if you send 599 001 001, the synchronizing is done three
times - once before the "5" and once before each "0". Your chance of
receiving the correct FIGS character has improved significantly.
So, here's a suggestion for folks who prefer using the hyphens:
Set up a separate F-key with ONLY the significant part of the exchange,
and do it WITH SPACES. For example, 001 001 001 001. Use it only when
asked for a repeat. In this example, the "synchronizing" space
character is sent four times, greatly improving the chances of correct
reception. Use this only when requested and it should not impact your
QSO rate/hour much at all, and I think you'll find your repeats are
reduced noticeably.
Enough. The horse is dead, my arm is tired and it's time to move on to
more interesting stuff like watching grass grow. :-)
Hope to see you in the SCC Championship this weekend.
73, Bill W7TI
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