Message-ID: <004301c188cb$86ba9d00$f39a17d2@steve>
From: "Steve Olney" <ollaneg@zeta.org.au>
To: rsgb_lf_group@blacksheep.org
References: <003301c186e8$dabdefe0$9fa1883e@g3aqc><5.1.0.14.0.20011217162715.00abb350@gemini.herts.ac.uk> <3.0.1.16.20011218145846.2b378612@pb623250.kuleuven.be> <007001c18807$c3f5d0a0$fb9a17d2@steve>
Subject: Re: LF: Re: long haul QSO's - SQUID...
Date: Thu, 20 Dec 2001 07:26:44 +1100
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G'day All,

Having done a quick scratchpad analysis of SQUID, it would seem that a
3-bit, 3-tone protocol won't produce enough unique codes. Will try 4-bit,
3-tone next.

The criteria I set for the sequences are pretty severe.   If someone is,
say, transmitting a sequence of ABC then running this continuously produces
a sequence of ...ABCABCABCABCA...     This means that if someone only gets a
three-tone snippet of the transmission, then sequences CAB and BCA can't be
used by other transmitters as they would be ambiguous with the ABC sequence.
This rapidly eliminates candidate sequences.

I was discussing this idea with my son (trying to get him intrigued enough
so that he would write some program to allow automatic generation and
selection of sequences :-) and he remarked that it was like trying to assign
an unique "genetic" sequence to each transmitter and "splicing" an
operational/signal report mode sequence onto that transmitter "genetic"
sequence.   Good analogy.  Maybe it should be called GENIE - for GENetic
IdEnt :-)    He also suggested that instead of "splicing" two sequences for
station ID and operational/signal report mode together, it might shorten the
sequences to combine them into one unique sequence.    Mmmm....   Good idea,
except I remarked to him that I am already in territory that few will want
to go and that extra step in decoding would not be attractive.

As Bob Vernall has indicated a "temporary" call register for ID sequences
should not cause too much angst.   On the LWCA site there has been
information about beacons for LowFer, MedFer and HiFer beacon for a long
time giving information about location, frequency, mode, operator, one to
five character ID, etc.   A similar table maintained somewhere on the Web
with an extra field giving the n-bit, n-tone sequence shouldn't be onerous.
Bob also points out that this idea is not without precedent if you consider
the single "Q" sent by himself instead of "ZL6QH" as a station ID.   That
transmission took 5-bits.   I hope to get a total of 8-bits to transmit an
unique station ID and operational/signal report mode.

If this idea is feasible one of the things that might need to be decided is
the number of required station IDs.   Taking the LWCA list as an indicator,
the LowFer list has some 60 odd participants.   So the absolute upper limit
would be, say, 60.    Accounting for willingness to move away from QRSSS and
other modes would surely reduce that to less than half (30).   Taking into
account interest, motivation, inertia, NIH and difficulty factors - I would
be surprised if there was a need for more than 15 (more likely 10) as a
maximum.    I will initially try for sequences assuming 20 station IDs
(these could be re-used or re-assigned for different bands).

73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40)
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