Date:    12/20/02 2:21 AM
From:    Luis Soltero
To:      Bulletins
Copy:    
Subject: Technology Update




Hello Every One,

This e-mail is specifically for our HF users. If you are a Satellite
only user please ignore this e-mail.

As you have all herd MarineNet is expanding it's services.

What you haven't heard is that in order to improve performance,
reliability, and coverage we are moving towards a new technology
called "FREE SIGNAL".

What is Free Signal you ask...

Let me start by describing what we currently have... explain
it's draw backs and then tell you how free signal fixes all these
problems.

You currently use HF scanning technology.  Our station in
Jupiter (wks) currently only has one transmitter.  It scans
through about 10 frequencies ranging from 4 Mhz to 18Mhz.
When you wish the connect to wks you must first scan all
the frequencies to determine if the transmitter is free.  Then
guess dial in a frequency, you broad cast into thin air hoping 
that WKS will pick up your signal as it scans through it's frequencies.

If wks happens to hear you then a connection is established and you
get your mail.

Problems with the scanning approach.
a) Just because you scan all the frequencies and hear nothing
does not mean marinenet is not busy broadcasting to another station.
If you happen to be in Trinidad and you can't connect it could
be that wks is communicating with a station the Bahamas on
a 4Mhz frequency and since this frequency is only active for
short ranges you hear nothing.  So you try to connect and
fail.

b) You the user must guess a frequency to use to connect
with wks.  If you guess wrong then wks may not hear you
in which case you don't connect, or you do connect but
have a horribly slow and long session.  If you notice a 
bad connection (lights mostly red on the modem) we
currently recommend that you disconnect and try another
frequency.

c) In scanning systems you the user establish the connection
to the server.    So you might be connected having a wonderful
e-mail session with wks and then some idiot tries to connect
over the top of you and every thing comes to a halt.  This situation
is caused because the e-mail client starts the connection to
the server and any one can start broadcasting at any time... I am
sure you have all suffered from this at one time or another.

Free signal fixes all these problems....  In a free signal system
the shore station transmits a continuous "free" signal at all
times except during a pactor session.

This means:

a) That there is exactly one transmitter per frequency.  No scanning.
If you want to connect to wks (or any other marinenet affiliate station)
you dial in to one of marinenet's supported
frequencies.  If there is a transmitter on the frequency that is ready
to do service you will hear the free signal.  No free signal 
no connection, no point in even trying... So you look on another
frequency.

b)  If you can hear the free signal well then you know you have good
propagation to the shore station and you will have a good pactor
connection.  If the free signal is week or just barely audible then
you are better off looking for another frequency.

c) Finally the pactor III modem will ONLY connect to the shore
station if it hears the free signal.. So once you are connected
and doing an active session NO ONE ELSE CAN INTERRUPT
YOUR SESSION! Again this is because the interrupters modem
will not hear the free signal and will not transmit. period.

d) Free signal also gives you higher availability because the transmitters
are not wasting time scanning.   

All this translates to shorter, faster, more reliable, less frustrating
connects....

So when will this transition happen....

Well it's happening as we speak... Our station in Rogers City Michigan
has 3 transmitters all doing Free Signal...

Our new station in Marathon Florida which is expected to be up and running
in production by the end of this month will also be a Free signal station.

My station in Knoxville, TN which should also be operational by the end
of this month will be a Free Signal station.

We expect that once the TN and Marathon Florida stations become
fully operational then WKS with two transmitters will also go Free Signal.
That will be a total of 7 transmitters doing Free signal into the Atlantic.

After the wks conversion we do not expect to support scanning
station ever again. (never say never they say...)

So what does this mean to you... Well fortunately the conversion
will not be difficult...  

Firstly, we will give you plenty of warning before we turn off the 
current scanning scheme.  Secondly you will have time to 
practice with free signal using our 3 free signal stations.

As the time approaches we will send you technical information
on doing the conversion... This conversion will require you
to do one of two things.
a) Download and re-install the marinenet software.

or

b) make a minor change to your modem settings.

That's it.

More on this subject soon.

--luis