rx.linkfanel.net receiver map moving to Leaflet

linkfanel · February 2020

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?

jks · February 2020

Tremendous thanks to Pierre for providing this service to the Kiwi community over the years and for his efforts with this latest update.

Note that map tiles for Leaflet are now served by the same provider used by the TDoA extension and admin page GPS tab maps. This means KiwiSDR is paying for those tile serves out of the profits from selling KiwiSDRs (same as we do for the charges incurred in running the proxy service).

rz3dvp · February 2020

Thanks @linkfanel !
Please add terminator line and cookie support for map settings...
For example if I use map layout I need choose it after any refresh.

linkfanel · February 2020

> Please add terminator line and cookie support for map settings...

There is already a terminator, but maybe it got lost in cache issues. I've remedied to that anyway, you can also try refreshing the page.

> For example if I use map layout I need choose it after any refresh.

Yes, good point.

> Note that map tiles for Leaflet are now served by the same provider used by the TDoA extension and admin page GPS tab maps. This means KiwiSDR is paying for those tile serves out of the profits from selling KiwiSDRs

Indeed, many thanks to John for offering to cover the fees!

G8JNJ · February 2020

Hi Pierre & John,

Thanks for doing this, it's much appreciated.

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.

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 ?

I must admit I'm biased about this as I believe that across the whole 0 - 32MHz spectrum, my KiWi http://southwest.ddns.net:8073/ is probably in the top 3 worldwide, although it's currently sitting at number 23 on the list with a S/N of 31.72 dB.

However when I have actually examined the spectrum display or performed an 'auto scale' test with the spectrum fully zoomed out I get better results (currently auto scaled as -22 to -114dB) than other KiWi's that are higher up on the list.

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.

Obviously the derived S/N values are not that accurate, as the percentile of power levels across the whole spectrum (signal), and the median power level (noise) depend upon the distribution of signals across the spectrum, how they are filtered and what unwanted noise is present that may seem like a valid signal. However despite these limitations, the S/N map is still the best way I've found to quickly sort out the really bad performers.

It's a pity that the http://sibamanna.duckdns.org/sdr_map.html map is no longer functioning, as that (at my suggestion) was modified to split the frequency range into several different blocks of spectrum, and gave average and current values for each, which provided a better overview of the likely performance, especially if you were interested in a specific frequency range.

I'm not sure how you can actually improve the S/N calculation without a very large amount of effort, but splitting it into bands and taking measurements at the same local time for each KiWi, may help improve the resolution.

Regards,

Martin - G8JNJ

kramcd · February 2020

Your work is helping everyone improve their setups (if they are wanting to do so). However, in all honesty I started using the http://sibamanna.duckdns.org/sdr_map.html website as well because if gave more frequent readings, graphed and gave noise floor readings too. As I'm on a steep learning curve, I found the more recent/frequent feedback more helpful making antenna changes rather than wait several weeks for the S/N figure...but hey, at least yours is reliable!!!
Also, some of the 'top' antenna scores are terrible setups, at least across the entire Kiwi spectrum. Many are overloaded and biased in one area and dead in other areas, they are not balanced performers at all. perhaps this is a metric that only the ear can discern?

WA2ZKD · February 2020

rating receivers is pretty tricky... I see few ranking sites that are indicative of actual usefulness of receivers

Bjarne · February 2020

@kramcd: I had no luck opening the sibamanna website.

ChrisSmolinski · February 2020

A few months ago I played around with ranking KiwiSDR receivers. It's quite subjective, to get anything close to reasonable you basically have to decide ahead of time which receivers are "good", which are "bad", and adjust your algorithm to rank them accordingly. That's made difficult by the fact that since different antennas are employed, a given receiver may be "good" on some bands but "bad" on others. For example if I put my 43m dipole on my KiwiSDR it's great in the 6-8 MHz range as you would expect but quite deaf on MW. Likewise for other antennas and bands. So you really do need to categorize the receivers by band(s).

What might be more useful is just trying to ID overall "bad" KiwiSDR setups. Those with poor sensitivity everywhere, or massive RFI issues (also often everywhere). I keep a mental list of which receivers to avoid overall, as well as which perform well on certain bands.

WA2ZKD · February 2020

If you were to look at some of the top voted RX on sdr.hu, they aren't so great. Overload and spurious on them.

WA2ZKD · February 2020

There are many KiwiSDR owners who use them for wspr spotting. KD2OM is one, who by using wsprdaemon and a 8 and 14 ch. kiwi on 2 different antennas is usually 1 or 2 in N. America or in the top 5 or so worldwide. I have 2 14 ch units are 2 antennas and am in the top 15 often in North America. That suggests that our setups are pretty good. The antennas I use for wspr are also on a 3 ch and a 4 ch kiwi at http://www.wa2zkd.net: 8073 and 8075. you can use those 2 RX on any ranking list to get a feel for the list's validity I think.

linkfanel · February 2020

> 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?

WA2ZKD · February 2020

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

I do not think there is anything in one spot. There are many excellent posts here in this forum. Here's a summary of my experiences:

Have a reasonably good antenna and keep it away from known RFI sources.
Be conscious of things like MW BC overload and apply filters as required
Avoid switching PSU, some are quiet but most are not so try to use linear PSU
Understand Common Mode Interference, read up on it, applies the easy remedies like use of ferrite core and intermediate grounding on your feedline
Watch for spurious using the [SPEC] display on a KiwiSDR client webpage, much noise can be noted by "lumps" of noise or spurs carriers at repeating spacing across a band
ID noise spurious by turning things on/off within your dwelling ot near the antenna
a partial list...

G8JNJ · February 2020

I agree it's a tricky subject.

"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..."

Maybe just a very crude indicator would be good enough and perhaps an incentive for KiWi admins to try and improve their 'rating'.

A 'traffic light' colour scheme (or similar) would perhaps help.

Red = <10dB
Orange = >10dB / <20dB
Yellow = >20dB /<30dB
Green = >30dB

Any KiWi's scoring less than 10dB definitely have a problem regardless of the merits of the existing auto scale measurement system :-(

The main issue with the current auto scale system is not so much the level of the strongest signals, but differentiating between noise and genuine signals in order to determine the noise floor. One way around this may be to sample a selection (in case a good signal just happens to be present on one) known 'quiet' frequencies in groups that are adjacent to each other (to test if the measurements are consistent, or if the noise consists of spectral lines) to build up a better idea of the noise floor in a few different segments of the spectrum. This could then be tested against ITU graphs to see if they follow the correct trend. It may even be possible to use this as another quality score, perhaps by measuring day / night variations, as I have found the variation in wsprdaemon S/N graphs give a good indication of the performance on each band by the individual KiWi's who are reporting

Regards,

Martin - G8JNJ

linkfanel · February 2020

I do not think there is anything in one spot. There are many excellent posts here in this forum. Here's a summary of my experiences:

What I was thinking about is that I'd gladly link from my SNR page to any such documentation to help people.

The main issue with the current auto scale system is not so much the level of the strongest signals, but differentiating between noise and genuine signals in order to determine the noise floor. One way around this may be to sample a selection (in case a good signal just happens to be present on one) known 'quiet' frequencies in groups that are adjacent to each other (to test if the measurements are consistent, or if the noise consists of spectral lines) to build up a better idea of the noise floor in a few different segments of the spectrum. This could then be tested against ITU graphs to see if they follow the correct trend.

The current approach can work regardless of the frequencies used. However, not all KiwiSDRs necessarily cover the same frequency range, and some also go up to 32 MHz somehow? So now you've got to make sure that waterfall pixels correspond to a given frequency, which isn't exactly the way the waterfall API works.

It may even be possible to use this as another quality score, perhaps by measuring day / night variations, as I have found the variation in wsprdaemon S/N graphs give a good indication of the performance on each band by the individual KiWi's who are reporting

The concept of comparing day spectrum and night spectrum to draw conclusions about quality sounds interesting.

G8JNJ · February 2020

Regards,

Martin - G8JNJ

G8JNJ · February 2020

Two more thoughts.......

The problem with Day / Night comparisons is interference from devices that are mainly used during the working day or solar PV.

A lot of interference is broadband in nature or has closely packed spectral components.
Measure the noise floor with a wide zoom setting say z3 and then measure it again on a 'quiet' frequency within the same frequecny range but zoomed in to z0, then compare the two values.

Regards,

Martin - G8JNJ

G8JNJ · February 2020

Yet another thought.

Would it be possible to include the auto scale max / min values and the difference between the two on the http://rx.linkfanel.net/snr.html page ?

I have noticed that in the top 30 many of the poorer performers have a minimum value of between -100 to -110dB whilst the better performers are generally -115 or lower.

This would seem to be because unwanted noise in the 20 - 30MHz spectrum (which is nearly always interference) raises the overall minimum value when auto scale is used.

If my theory is correct, I would hope that by showing these values it may indicate further trends and help indicate differences between the best and worst performers in each 'tier' of ranking.

Regards,

Martin - G8JNJ

kramcd · March 2020

Being selfish here...Perhaps two SNR values, eg. over last/longer period (say two or more weeks) and a more recent/shorter period (say last week or current period to date)?
I understand an average is more meaningful over a longer time, but something shorter could be useful too.
Thanks for asking for feedback!
Mark.

WA2ZKD · March 2020

Not sure what freq ranges are scored but my RX at http://www.wa2zkd.net:8075 is intended to work for the range 1.8-30 MHz. Antenna type and filters severely limit performance below 1.8 and should not be counted. the /status url option gives the sys op's intended freq. range if set.

Note to sys ops, you should set and freq. range to reflect your RX's performance which is a product of antenna range and applied filters.

ricardo · May 2020

hi,
my kiwi does not appear on sibamanna and is listed on sdr.hu.
thank you
Ricardo

http://py4aaz.homeip.net:8073/

Powernumpty · May 2020

sibamanna holds old data, mine is listed but as it was configured perhaps six months ago.
To be honest I didn't know it was back up.
I have emailed the guy in the past and he was quite helpful but I guess this is not something he gets enough payback to work on.

Howdy, Stranger!

Categories

rx.linkfanel.net receiver map moving to Leaflet

Comments

Howdy, Stranger!

Quick Links

Categories

rx.linkfanel.net receiver map moving to Leaflet

Comments