Bob,
In the context of multiple antennas & skimmers, I'm curious about this data analysis use with skimmers.
Maybe it's been discussed before, but the RBN reports of the same
station from the same skimmer vary quite a lot over time in my
observation. I've noticed this in many contests where I may have
two screens of the RBN website feed up - one looking at my signal
and another looking at another guy who I'm interested in comparing
too, to see how we look at a single given skimmer site. In this
case, these reports can vary by 10+ db very easily, especially on
the lower bands.
Why I'm thinking about that flows from your comment on the data
analysis and it reminds me that I have seen some guys talking on
the reflectors about using RBN reports for fine tuning antennas
where they are considering changes that are in the few-dB range
and using RBN as the measurement method. I don't understand how
that can be done with precision given the variability the
atmosphere provides in cases excluding ground wave prop. It seems
like the noise in the data would swamp the relative compare value
for this objective.
Skimmer reports SNR so both the noise floor skimmer sees as well
as the signal(s) of interest needs to be stable over time so that
Skimmer is able to provide a repeatable report (at least within a
short measurement window). Otherwise it seems like a guy would
need to have two very different antennas (for example one skimmer
tied to his TX vertical and another one tied to a low-noise
directional RX) so that the SNR difference would be significant
enough to overcome the prop.
Maybe there is a statistical method that addresses this? Or maybe
I'm missing a key point here that is otherwise obvious?
73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com
If you have two skimmer instances monitoring the same frequencies, they should never post under the same Skimmer callsign, otherwise the reports will be quite useless for data analysis, because the signal reports will be bouncing all over the place and you can't tell which report to use. Eliminating dupes alone doesn't solve this problem, because the same station could be reporting with two different signal strengths every few minutes, depending on which skimmer heard it first.
If the two SDRs or two Skimmers are monitoring the same band segments, use 3V8SS-1 for one and 3V8SS-2 for the other. You need to run two independent copies of Aggregator to make this work right, since the posted callsign is determined by the first SkimSrv.ini, not by Aggregator.
For more details explaining how to do this, please review this post by Aggregator author W3OA:
73,Bob, N6TV
On Sun, Jan 26, 2025 at 6:12 AM Ashraf Chaabane <ash.kf5eyy@gmail.com> wrote:
Hi All,
I use two receivers with separate receiving antennas. Both are skimming
to Aggregator. How can I ensure Aggregator doesn't send the same spot
twice if it happens that they come from both receivers?
73 Ash 3V8SS
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