[aprssig] Throttleing EchoLink Objects

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Wed Jul 22 19:40:12 CDT 2009

If the goal is for rating based on range, why not base it on the range 
as calculated from the PHG data provided by the EchoLink operator and 
the equations from aprs101.pdf.  I just analyzed the current EchoLink 
node status and found the following count of nodes in 10 mile range 

Range[0] = 867 (>0 - <10 miles)
Range[1] = 466 (=10 - <20 miles)
Range[2] = 200 (=20 - <30 miles)
Range[3] = 98 (you get the idea)
Range[4] = 73
Range[5] = 43
Range[6] = 37
Range[7] = 17
Range[8] = 25
Range[9] = 5 (I'm mildly skeptical here)

2030 Stations Online, 849 Offline, 0 Unknown  (1831 with >0 range, see PS)

If I did my math right, a mobile driving at 70 mph covers 1.16 miles per 
minute.  Figuring a 10 minute update and 10 minutes for a QSO, that 
means we need 20 minutes of range.  20*1.16 is about 23.33 miles of 
range assuming we're driving along a radius right under the EchoLink 
tower.  If we say that we only want to beacon those stations with >20 
mile range every 10 minutes, that drops the 1,831 stations to 498.  If 
we restrict ourselves to 30 mile range (more reasonable as it allows for 
(geometric) chord crossing of the circle, we're down to 298 stations, 
only 16% of the original.

Some sort of scale factor where higher coverage nodes get more frequent 
beacons (max of 10 minutes) seems like an idea worth exploring.  If we 
go with some sort of calculated rate based on range (where'd my 
simplicity go?), we end up with something that will randomize the 
beacons over time as well.

Any statisticians out there that can take my rudimentary table and give 
us some rate estimates as well as possibly describe an equation to 
convert from range to rate?  Oh wait, I think I can do that...Nah, never 

Lynn (D) - KJ4ERJ

PS.  If you added up the range totals and compare with 2030, you'll find 
199 missing stations.  These are stations with ZERO range.  Hardly worth 
beaconing at any rate IMHO.

Bob Bruninga wrote:
> Here is an idea for throttleing the EchoLink objects:
> Looking at the PHG data from the Echolink server, probably 80% of the Nodes have a PHG under 50 feet.  A home link-L station with only a HAAT of 40 feet is going to be useless to a mobile operator because it is not there but for 8 minutes max as he drives by at 70 MPH.  (I am guessing, but can work this up later)
> And the probability that a mobile is in range of a node goes up as the SQUARE Of the HAAT.  So one that is at 160 feet will be 16 times more accessible. and the mobile will be in range of it long enough to make a QSO, even if its 10 minues before he sees it.
> I am at home now and cannot easily look at the raw data, but I'd try this rule:
> Anything above 100 gets 10 minute rate, everything else, hourly.
> Now I konw this is kinda backwards, but  everything below 100 feet which has such a short range, there is no reasonable rate that will make it useful to the traveler, so we are only putting those out for LOCALS to build up their LOCAL visualization of their area.  They accumulate this over whatever time it takes.
> So, What would that do to the data if we only did the 10 minute rate on the >100' HAAT stations?
> Bob, Wb4APR
> Bob, WB4APR
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