[VHFcontesting] Understanding HamIM

Ev Tupis w2ev at arrl.net
Wed Sep 8 19:51:52 EDT 2004

Since the topic came up...

HamIM is APRS on a simplex frequency (no digipeating) with no Internet gateways. 
  For many on the list, that is enough explanation as to just how easy it is to 
participate.  For the rest...

WSJT vs. HamIM
WSJT gets you distant grid squares.  HamIM gets you every local QSO and grid 
possible.  They compliment each other nicely.

WSJT requires a computer, soundcard, SSB transceiver and software.
HamIM requires a computer, soundcard, FM transceiver and software.
   -what about the talk about packet TNC needed? Forget about it! Use AGWPE,
    a soundcard TNC emulator: http://www.qsl.net/soundcardpacket/ if you don't
    want to use a TNC
   -for better performance, a KISS-capable packet TNC will do better, but it
    is not a necessity, as noted above.

Simply get your system running on APRS, then QSY to 147.585 FM for the contest, 
and change your configuration to simplex operation (a simple thing to do).

What can you expect?
 From a home-station's perspective, you will see the rovers on the hilltops or 
across the plains.  The higher the power of the Rover, the farther away their 
effective HamIM range will be.  It is not unthinkable for Rovers to eventually 
pack 160 watt amps for their HamIM operation!

 From a Rover's (or hilltop stations) perspective, you will see a LOT, because 
your horizon is that much better than the typical home station.  Here's a 
screenshot from a recent VHF contest, from the perspective of a rover on a 
hilltop: http://w2ev.rochesterny.org/HamIM/images/HamIM-FromRover.jpg

The cost to participate is incidental (a 50-watt FM transceiver on eBay can be 
had for under $140).  The advantage to assuring that you don't miss any rover in 
range is significant.

In Western NY (my house), HamIM range is 6-grids for a 50-watt rover.  Three N-S 
and two E-W.  I would bet that the range in the Great Plains is 
s-i-g-n-i-f-i-c-a-n-t-l-y greater.

HamIM will enable you to be notified whenever a rover is passing through. 
Imagine the power of the system for Rover to Rover contacts in remote areas!  It 
will also antiquate the need to post schedules.  When they're "in the area", 
they'll show up on your screen! :)

Ev, W2EV
More info at http://w2ev.rochesterny.org

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