linkfanel

I have just switched the markers on the map to use the new self-reported internal SNR scores. The logic is as follows: the HF-only self-reported score is used if available, if not the full-spectrum self-reported score is used instead, and if no self-reported score is available, the classic external score is used as fallback; this last case is mostly about receivers running an older version of the software.

Users choosing a receiver will benefit from up-to-date and instantly relevant scores, as by default self-reported scores are calculated every hour. As such you may notice how marker coloration now brightens up when nighttime comes and covers their area. HF-only scores are favored as it was pointed out that very strong MW bands tend to skew the scores. I don't especially like excluding signals below 1800 kHz, but a choice has to be made since it makes a significant difference in usefulness; and this is a shortwave receiver map, not just a map of remotes for commercial MW band broadcasts, so this is our editorial line.

Thanks to everyone involved for their contributions to the discussion, scoring code or monitoring framework. In the future I'm fine accepting as input whatever KiwiSDR receivers calculate and report as SNR score, so don't let the fact that the map uses those scores hinder further change or refinement about them :)

About the purpose of the scores, and what score to use, I think there are several use cases, or maybe several schools of thought.

• Some people want a measure of performance of the receiver right now, because they want to choose one to listen to a signal right now, so that's what matters: for this, the best would be the most recent instant measure possible.
• Some people want a more general or abstract measure of performance, perhaps for self-improvement, perhaps to find a generally good receiver without a specific time or signal in mind - so a measure that doesn't depend on the time of the day: this would need for example a straight average of measures over at least a day/night cycle; Mark also suggested, instead of the average, taking the maximum SNR value over that cycle.
• Some people look at this with an even broader scope, and see this as a performance indicator that goes beyond external disturbances such as daily propagation conditions, space weather, temporary QRM, maybe even seasons: a simple solution for this would be a classic stateful metric, where each new measure updates the metric with only a partial weight - for example, the new updated score would be 90% current cumulative score, 10% new measure.

Of course, the SNR listing, the map markers and so on are different tools with different purposes, they don't have to use the same approach if several scores are available; this isn't one size fits all. I guess there's no problem displaying all available score options in the listing; they just have to be available. For the map, I think I have to choose what I do, but I'm listening.

That's no technical issue for me, it really makes no difference with the current state in that regard.

> I find the S/N map and rating list extremely useful, especially when trying to optimise my own KiWi's and also when trying to find KiWi's that are suitable for TDoA purposes. In fact it would be really useful if the TDoA Kiwi selection map could somehow indicate the S/N ratings of each in order to make the selection process quicker by ruling out KiWi's with really bad (unusable) S/N values.

There are many approaches to the topic of S/N ratings. You've mentioned splitting the spectrum into several bands, there is also the question of how frequently and what time measurements should be made. In the case of TDoA, you actually know the exact frequency you need information about, and over what time span (right now); so an approach I've heard being suggested would be to probe all KiwiSDRs on that frequency, sort the best ones for that particular signal right now, and then work only on those best receivers.

> Its main competitors (by manual examination of the spectrum display of each) are http://nsk.proxy.kiwisdr.com:8073/ with a listed value of 40.35 dB (currently auto scaled as -17 to -115dB) and http://kphsdr.com:8073/ with a listed value of 32.79 dB (currently auto scaled as -35 to -118dB). All the rest I have currently tried in the top 20 on the list are worse performers, but it does depend to a certain extent on local time at the KiWi and propagation conditions.

Indeed, the ratings as they are now would depend a lot on whether it's measured at day or night, and they're most useful for discriminating between receivers in the same area (which get measured at the same local time).

> I'm not sure how frequently the S/N values on http://rx.linkfanel.net/snr.html are updated, but maybe an 'average' and 'recent' display would be worthwhile additions ?

Data visualization is a trade in itself, as well as an art. In the case of this map in its current form, without adding any interactive filtering feature, it's a game of reducing or projecting complex objective or subjective quality metrics down to a one-dimensional score. The alternative would be to make the color gradient bi-dimensional, or somehow cram more information into the marker while keeping it uncluttered and visually straightforward...

I agree that "average" and "recent" are both valid approaches though. At this point I favor the one that puts less constraints on me and the infrastructure. As I mentioned above with TDoA, different approaches are best suited with different use cases in mind, so improving quality metrics goes hand in hand with developing new ways to use them.

Relative to that topic, is there any how-to, guide or documentation anywhere to improving and tuning reception quality on your KiwiSDR?

Due to increased traffic, the new pricing practices of Google Maps had finally caught up with us with the new year, hence the pesky "For development purposes only" dark overlay you may have noticed on the map for more than a month now. We've taken this opportunity to make several updates and improvements, including alternative support for the Leaflet API.

We hope to bring you a better experience, especially on mobile. If you encounter any new issue with the transition to the new map, or have any other feedback, please let me know and I will try to look into it.

Thanks to jks for his help and support in setting this up!

http://rx.linkfanel.net/

Which improvements would you like to see added to the map?

Due to increased traffic, the new pricing practices of Google Maps had finally caught up with us with the new year, hence the pesky "For development purposes only" dark overlay you may have noticed on the map for more than a month now. We've taken this opportunity to make several updates and improvements, including alternative support for the Leaflet API.

We hope to bring you a better experience, especially on mobile. If you encounter any new issue with the transition to the new map, or have any other feedback, please let me know and I will try to look into it.

Thanks to jks for his help and support in setting this up!

http://rx.linkfanel.net/

Which improvements would you like to see added to the map?