[aprssig] APRS BEACON MTG INFO

[lawrence labranche]

Interesting. Thanks for the info. In the programming software for Kenwood th-72a 
the high speed mi/h setting max is 90.
-Larry KI6ZQY 73


----- Original Message ----
From: Rory Burke <rory at burke.ac>
To: Bob Bruninga <bruninga at usna.edu>; TAPR APRS Mailing List <aprssig at tapr.org>
Sent: Thu, March 10, 2011 8:34:51 AM
Subject: Re: [aprssig] APRS BEACON MTG INFO

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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