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[aprssig] APRS BEACON MTG INFO

Rory Burke rory at burke.ac
Thu Mar 10 16:34:51 UTC 2011


On 3/7/11 5:16 PM, Bob Bruninga wrote:
>> So if they are listening to you, is there any chance they might fix the
>> crippled High Speed parameter in SmartBeaconing as well?
> Never heard of it.  Can y ou provide a detail description and examples?
>
> Thanks
> Bob, WB4APR
>
> 73 - Rory - K5MBH
In order for SmartBeaconing to work as conceived and provide 
distance-based beaconing rather than time-based beaconing you have to be 
able to set the High Speed parameter to a speed that is high enough that 
you'll usually never exceed it.  Right now the Kenwood and Yaesu radios 
that support SmartBeaconing limit the High Speed parameter to 60.  
That's VERY marginal for the USA and useless for anyplace that uses the 
metric system.  For SmartBeaconing to work correctly the limit on the 
High Speed parameter needs to be more like 120 or 150.  Once the High 
Speed parameter is reached the radio reverts to time-based beaconing 
rather than distance-based beaconing.

Here's an easy way to set it up so you can do the math in your head for 
US based hams.

First, set the High Speed parameter to a "convenient" speed that you 
probably will never exceed. Using 90 mph makes the math easy.

Once you set the High Speed parameter to 90, you can then calculate the 
distance between beacons using the formula of 1/8 mile of
distance between beacons for every 5 seconds of Fast Beacon Rate.

So, if you wanted your beacons to come 1/2 mile apart you'd set the Fast 
Beacon Rate for 20 seconds (1/2 mile = 4/8 mile x 5 seconds per 1/8 mile 
= 20 seconds.) If you wanted your beacons to come 2 miles apart, you'd 
set you Fast Beacon Rate to 80 seconds (2 miles = 16/8 miles x 5 seconds 
per 1/8 mile = 80 seconds).

Once the fundamentals are grasped, it's a trivial matter to calculate 
the distance you want between beacons, as long as you've set the High 
Speed parameter high enough that you'll never exceed it.

Remember that this doesn't mean that your beacons are going to come 
every 20 seconds (or 80 as the case may be). These settings will cause 
your tracker to beacon every 1/2 mile (or every 2 miles). Whatever 
distance you set your Fast Beacon Rate for will be maintained all the 
way up to the High Speed parameter.

The equation breaks down if the High Speed parameter is one that you can 
exceed, because if you exceed the High Speed parameter, you get constant 
timed beacons rather than constant distance beacons.  And that being 
said, those using the metric system need even higher High Speed limits 
than we do in the US.

Corner pegging is a whole different kettle of fish that I chose not to 
address here.  Suffice to say that the current limits on the corner 
pegging parameters seem to work just fine.

73 - Rory Burke - K5MBH



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