[aprssig] Road Trip so far...my experience

[Robert Bruninga]

I can offer a tip.  Remember that just because you dont see
a MY PACKET copy comnfirming you were digipeated, does
not mean you were not digipeated.  In fact, probably 1/4
of the time you wont see it in a properly working network.

This is because the network is supposed to have all digipeaters
that hear the initial packet to all digipeat it at once and
only use up one time slot, not multiple time slots.  This
lets the packet radiate outward N hops in N time slots
and not N-times-N time slots which really ruins network
efficiency.  So if you see a SIGNAL STRENGTH burst
immediately after your packet, but no MY PACKET, then
not only were you digipeated, but your packet actualy
hit two equidistant digis and got launched in both directions
at once.  This is why you are on FINDU in some areas even
though you never saw th econfirmation beep.  de WB4APR

>>> "Brian Webster" <bwebster at wirelessmapping.com> 06/18/06 11:04 PM >>>
Great report Joel. Nice to hear a trip that is successful. Your Iowa
experience mirrored mine quite a few years ago. I brought my HT, TNC and
laptop. No sooner did I fire it up in a Des Moines hotel room when I watched
a truck come in from Nebraska and followed him in to Illinois on my map
without being connected to the net. I give the Iowa group a lot of credit
for a good network. Your trip through NY should produce pretty good results.
I'm not sure of the state of things in NYC but the rest of the state is in
good shape. Have a safe trip and I hope to hear an update on the rest of
your trip. I'd be curious to see if your system works as well if you just
set the path to WIDE2-2 only. That is what I run on my TinyTrak and am quite
happy. I get the feeling that with the new paradigm, the fill in home
stations are much less of a necessity. I run my tracker with a 5W HT and a
quarter wave whip. I've never done a detailed long trip review like you
have, but when people checked on me via the net they always seem to get good
results in that the packets are not that old. Might just be that I was
always in good coverage areas, might be that the new paradigm really does
work as we needed it to over most areas.



Thank You,
Brian N2KGC

-----Original Message-----
From: Joel Maslak [mailto:jmaslak-aprs at antelope.net]
Sent: Sunday, June 18, 2006 10:42 PM
To: TAPR APRS Mailing List
Subject: [aprssig] Road Trip so far...my experience


I am in Toronto, and have taken people's advice and honoring the
spirit of the law by transmitting my position when I ID - in other
words, my normal, every-day, US APRS configuration.  :)

The trip from Wyoming (via Denver) to Toronto was interesting, I
followed a few people on the interstate but never observed anyone
coming the other way or within what would be reliable simplex range.

I was surprised with how good coverage along I-76/I-80/I-94/401 is.
There were certainly spots where I heard no digipeat, and I drove
through some moderately crowded RF networks.  Things do act
differently on crowded nets, I certainly had many less packets
successfully digipeated, and I can see how it would tempt a user to
run higher power and more frequent beacons (I resisted both urges!),
only making the problems worse for everyone else.

Looking at Find-U, there were very few places where I didn't make it
into the Internet.  There were gaps in every state I drove through
(the biggest gaps being north-eastern CO and western NE, where I
could go hundreds of miles without hearing myself digipeated.  Iowa
was the opposite - I had coverage almost from border to border, and
almost always heard myself digipeated successfully for the entire state!

I think Toronto is a bit hard on my D700 receive (not having sent
time being able to debug exactly why my radio seems deaf in Toronto,
I'm guessing there is just too much general RF around here).  But I
am getting out, and am even being heard direct by a downtown station
that gated my packets to the internet (I was shocked to see that,
since I hadn't heard a digipeat of my packet since I turned south off
of 401 to head to my current location on the south edge of downtown).

N0YXV apparently messaged me to tell me about a passing another
mobile APRS station, K3BZG-9, but I was likely on the edge of
coverage and my signal was probably getting out better than I can
hear...  That's unfortunate, it could have been fun if I noticed the
other station.

The equipment has worked flawlessly other than the receive
performance (which isn't horrid but isn't great either - I'll have to
see what I can do about that when I get back home).  Everything has
been rock-solid, which is amazing.  It's required very little
adjustment and set-up - I turn the GPS and D700 on, and it just plain
works - and best of all, I can still participate as a 2-way station
(instead of just as a tracker; No, I don't do 2 way communication
digitally while driving!).  I've built a few trackers and such, but
almost all of them suffered from cables getting disconnected and
such.  It's nice to not have that problem with my current installation.

The only other problem is that I am not used to parking garages, and
even the 5/8 whip on the trunk deck hits the ceiling in the parking
garage I parked in today (SCRAAAPPPEEEE...  Oh $#@!, I left the
antenna on the car!  Stop, hold up traffic, and remove both 2m
antennas...)

I've kept my path at WIDE1-1,WIDE-2-1 for the entire trip.  Along the
Colorado front-range, I heard up to *8* repeats of each packet, even
on 5 watts power.  But elsewhere I never heard more than 2 or 3, and
most of the time just 1.  I adjusted power when it sounded like I was
making it into the digi well, although I'm curious whether more or
less power is likely to cause the least interference and if turning
power down may actually make things worse, because of the hidden
transmitter problem - ideas, anyone?

There hasn't been anywhere yet that WIDE1-1,WIDE-2-1 hasn't worked,
at least not anywhere where I was able to hear other stations.  So
even though everything may not yet fully implement the "new
paradigm", it does seem that most existing digis do support new-
paradigm stations.

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