[OZAPRS] Re: The Guide ....

[Terry Neumann]

Hullo Richard and others,

Some observations from someone who is on the outer edge of this mode, 
and which may or may not generate discussion......  

Perhaps I'm being fussy but comments were invited, so here goes....


snip

>As HF APRS is becoming more popular in Australasia I have put together a
set
>of guild lines that we all need to adhere to. This will allow the
successful
>long-term use of the ARPS HF 10Mhz network as it's popularity continues
to
>grow.
>
> 
>
>The Do's and Don'ts for APRS HF.
>
> 
>
>Do's
>
> 
>
>1.	Do consider all other users of the HF network. Remember you are
>sharing this single frequency with hundreds of other operators.
>
I have no quarrel with the sentiment in this point.   However, the 
"hundreds of other operators" worries me.....   My MH list runs to about 
5 or 6 stations most days.    One day there might be "hundreds", but I 
don't think there ever will for reasons which are outside of this 
immediate consideration.    


Snip

>Don'ts
>
> 
>
>1.	Don't Digipeat any packets on HF (the only exception is for tuning
>your radio).
>2.	Don't transmit Home station positions on HF. Only Gates and Mobile
>stations need to transmit position information.
>
I think I know the reasons for this last point (2), but it certainly 
seems to defeat the purpose of the whole exercise.  What is the point of 
transmitting at all if the position information is not given?  

(I have similar concerns with earlier discussions which suggested that 
mobile stations shouldn't transmit speed and direction, but only 
position.   Fact is that stations who are transmitting speed and 
direction in addition to position are getting their message through, and 
it makes for much more interesting viewing).

This mode will never attract significant numbers of other users if we 
don't make it as interesting as we can whilst people who might be 
interested look in at the SWL stage.   It's about positions on a map at 
this early stage; it's the next development beyond the MH list.    At 
some point in the future perhaps perhaps we can filter down the amount 
of info in our beacons, but surely not just yet.  

These are my own observations as one who is interested, doesn't always 
appreciate the finer points of the discussion, but remains interested - 
for the time being anyway.   However if it wasn't for Warren's speed and 
heading information which I see on most days I probably wouldn't 
bother.   Now I know that this last point is outside of those raised by 
Richard in his guide, but  it's related by implication of earlier 
discussions, and the essential thrust of what is being reinforced by 
other points in the guide.

It's not easy writing a guide Richard; thanks for doing so.   If the 
points I have raised bring out some constructive discussion I'll be more 
than satisfied. 

73
Terry
VK5ATN

>Remember that an average length APRS Posit packet takes 3 to 4 seconds to
>transmit on HF. Assuming a channel efficiency of 30% for ax25 this
results
>in a maximum of 7 stations being able to transmit per minute. At a
>transmission rate of one posit per 10 minutes the maximum number of
stations
>that can be in a single APRS Gate's coverage area is 70 stations. This
will
>be less as the Net stations transmit frequently and messages  and/or
tuning
>may be under way on the channel. HF Propagation is also an important
factor
>in limiting station numbers.
>
>  
>

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