In order to correctly evaluate the accuracy of the RBN versus
traditional spotting, I think you need to start with the idea that
the RBN is not a traditional spotting network. Here's what I
mean.
Accuracy of a properly set up CW Skimmer in copying callsigns runs
right around 99 percent. There is an as-yet-unresolved problem
with copying callers as if they were runners - more on that
below. But let's assume the 99 percent is right for an individual
Skimmer, one not assailed by local RFI.
If you consider the RBN, on an open band, with no spot filtering
by spotter location, then the picture changes. Suppose you have
30 Skimmers in zones 4 and 5, all copying an open band. Each
running station will be spotted every 10 minutes by each RBN
station, so long as the station remains on its run frequency. You
could, theoretically, have as many as 180 spots of each running
station every hour. In that case, simple probability says there
will be roughly 1.8 busted spots per hour of each one.
If you are sitting at a big multi-op, receiving spots from all over the
world, or just all over the US, then it is almost inevitable that
you will see busted spots a lot more often than from the Cluster
network. Not only are there 10-15 times as many spots, but there
will be busts of many running stations, just by the math. On
Sunday, you will see tons of busts, because by that time you will
have worked most of the good callsigns, leaving only the busts on
your bandmaps.
There are several partial solutions, not all of which will be
implementable at a big multi, but let me mention a
few:
* Filter by spotter location, so that you only get spots from
stations who are probably hearing the same things as you can. For
example, I filter by spotterstate = MD or PA or VA or NC or WV
(have to get my own spots too). That cuts down the number of
Skimmers feeding my bandmap to 7-8, sharply reducing the
probability of busts.
* Use the "Unique > x" filter in AR Cluster version 6. That
filter only passes a spot if at least x+1 Skimmers worldwide have
copied the same spot the same way in a relatively short period of
time. This helps a lot to winnow out busts, as you can imagine.
The RBN has a very robust ARC6 node at
arcluster.reversebeacon.net, port 7000.
* Use a logging program that permits displaying unworkable spots
(already worked, or not workable in a given contest) on the
bandmap. For example, N1MM Logger displays such spots in gray.
The advantage of doing this is that if LZ9W is running, but you
worked him 30 hours ago, and LZ9WL suddenly shows up on the same
run frequency, you can see that it's pretty likely to be a bust.
This also helps with callers mistakenly identified as runners; if
you see calls appearing one after another on the same frequency as
one of the big runners, you're probably safe in skipping past
them.
We hope this is helpful.
73, The RBN Team
