Less than optimum SDR's online.
I find it somewhat frustrating to visit some of the online KiwiSDR only to find they are full of SMPS/RFI and unusable. Sadly it makes the experience poor, and often put people off using what in the main is an excellent resource. I know the + vote system is supposed to help, but I would really like to see the receivers ranked by performance. (maybe including a + and - button) If a receiver is poor or very poor, it really shouldn't be presented in the list as it distracts from the hard work, time and money some people have put into getting their SDR online.
Don't get me wrong, my SDR isn't perfect, but its a lot, lot better than some.
I guess its quality control, has anyone thought about how we can ensure its about the quality of receivers online, and not just the quantity..
Dave M0TAZ
Comments
I'm the maker of http://rx.linkfanel.net/ so I've thought a bit about these issues. In my opinion the upvotes on sdr.hu stem from a good intent, although they're not a terribly great or effective idea. It tends to be skewed towards older receivers, or receivers that are already popular - the only way to upvote is from the rated listing itself. I've emailed Andr?s back in February regarding the use of his data, one of the things I asked was:
"What would you think of using additional information to rank receivers, other than votes, for example visiter count or total listening time or rates of these? These would have to be reported by the receivers somehow. I guess more direct metrics like reception quality would be much harder to quantify."
His reply: "That's a good idea." However it wasn't actually followed by any positive development.
You also have to consider that a ranking "good" receivers at the top and "bad" receivers at the bottom is hardly an end by itself. There are many factors in which receiver one would pick, location would be a big one. Personally I look for a receiver in the area I'm interested in first, and then I try to pick one offering a quality reception, if there's more than one available. Of course this is tooting my own horn because I developped tools for that purpose.
I'd love to add some representation of receiver quality to my map, but I'd need usable data to base it on. Andr?s even declined to allow me to use his data at sdr.hu for my map.
Upvotes aren't terribly great. There could be more, possibly better metrics, like usage, that I mentioned to measure popularity. However just because a receiver is used at all times for some kind of monitoring doesn't mean it's actually popular. And popularity still does not equate quality.
Actual quality metrics would be better, but shortwave is complicated and as I said it's difficult. Could there be some kind of metric built in KiwiSDR based on signal-to-noise ratio? If I look at a waterfall display and see strong signals standing out of weak noise, that's a good indication, especially if across all the spectrum; and that might be something possible to automatically calculate.
The antenna field can be an indication of quality too, however not necessarily reliable or easily exploitable.
I've developped https://github.com/priyom/pavlova and found that the best approach to pick and rank good receivers was still to try and test them one by one, compare and get a subjective appreciation of how well they receive, and curate a list by hand. Even then that's a partial rating for a very narrow purpose.
Of course we should also help and make it easier to improve the setups and quality. Maybe filters could be bundled with the KiwiSDR when it's shipped, that might be the best way to be sure they make it to the people who should have them. Maybe there could be an interactive checklist in the admin page with items to tick to set up the receiver: registration, opening network access, proper antenna setup, installing filters, hunting for noise sources. It could calculate a score saying "your receiver is X % set up", like those online profiles do. Of course some people don't want to bother with that and have no advanced interest in making a great receiver; and that's okay too!