Best Recent Content

  • Hackers be hacking..

    jksjks

    v1.682 fixes the problem reported by @HB9TMC where ipset/iptables wasn't filtering properly (but the Kiwi server was as a backup).

    But I also noticed something important. On the admin network tab, the "local blacklist" section where you can enter your own ip addresses and ip ranges: Be careful to not enter invalid or duplicate entries. Especially duplicates. Because processing of the local list will terminate at the point it finds a duplicate. It's a pain for me to detect this condition and report it back to the admin interface. I have much more important things I need to be working on. So this warning will have to suffice.

    Consider this local blacklist entry:

    1.2.3.4/32 217.150.74.0/16 217.150.75.255/16 5.6.7.8/32

    There are two problems here. 217.150.74.0/16 is deceptive because the /16 means the bottom 16-bits are considered the wildcard host address part and should really have been specified as 0.0 as in 217.150.0.0/16. That means the following 217.150.75.255/16 is also wrong and also considered as 217.150.0.0/16. Hence two identical entries in a row causing an error which prevents the 5.6.7.8/32 entry from being added to the blacklist!

    So be careful when constructing your lists. Use a site like https://www.ipaddressguide.com/cidr to check your IP range for proper CIDR representation.

    Yogicat

  • Mouse wheel to tune the frequency?

    G8JNJG8JNJ

    I should have clarified the way it works a bit better.

    Pushing the mouse wheel down whilst rotating it enables the opposite mode to the default that has been chosen. in OpenWebRX.

    Having the possibility to tune using the mouse opens up other possibilities such as making your own VFO knob, using the optical encoder recovered from a scrap mouse, or buying one of the more expensive ready-made commercial items.

    If it could be implemented in a way similar to that of OpenWebRX , then it would still retain the mouse wheel zoom option for those who prefer it, but offer an alternative for folks who would like to use mouse wheel tuning.

    Try it and see for yourself.

    http://wessex.hopto.org:8060

    If you open up the settings pane in the control panel, you should see the "Hold mouse wheel down to tune" tick box. Also set the tuning step size in the controls section, 500Hz or 1kHz is useful for SSB, as most folks use 'rounded up' frequencies.

    I'm not specifically requesting this feature, as I don't wish to add to John's already massive workload of much more important issues, but I can understand the appeal of it.

    Regards,

    Martin

    Yogicat

  • Please protect your KiwiSDR 2 from the high-level RF fields of nearby transmitters

    DenBozDenBoz
    PXL_20240421_221307644.MP.jpg

    since i have a small garden and live in a urban area..all my antennas are real close .so i have used a antenna switch unit. so the moment i am transmitting on hf or vhf the radio is short to ground and a relay is activated to protect my sdr radios. so the antenna signal to the antenna distribution block is no longer connected to all my receivers. also raspberry with 5 rtl dongles are on the switch, better safe than sorry.

    Nate_RF5AFY

  • Problems with frequency stability

    jksjks

    You only have 3 sats in the az/el display which is the bare minimum to maintain a lock (assuming they're strong enough to be tracking & decoding properly).

    What happens if you turn off GPS, do a manual calibration, and just let it free-run?

    wd4elg

  • Please protect your KiwiSDR 2 from the high-level RF fields of nearby transmitters

    jksjks

    Please make sure your Kiwi is adequately grounded. So the antenna input protection circuitry has a path to drain any charge it is intercepting. Ideally this would be on the antenna coax near the RF in SMA connector. Or from the Kiwi metal case.

    The ground connection from a switch mode power supply is likely not earth grounded and the Ethernet cable is transformer coupled with capacitive bypass.

    F5AFYNate_R

  • 8-10dBm drop in signals after update from v1.601 to v1.675 [fixed in v1.679]

    jksjks

    😕 Knowing that, I developed and tested a fix for this problem in about 10 minutes. Fix will be in the next release..

    nitroengine

  • Suddenly my WSJT-X decode counts are much lower

    jksjks

    For future reference. The conversation continued here: https://groups.io/g/wsprdaemon/topic/my_wsprddaemon_decode_counts/105934346?dir=asc

    Nate_R

  • Software defined lighning detector?

    HB9TMCHB9TMC

    Finally a use case for my 10 Gb/s internet access 😁

    Nate_R

  • Software defined lighning detector?

    jksjks

    Christoph has done work with piecing together (relatively) wideband output from the Kiwi to measure ionogram chirps: https://hcab14.blogspot.com

    HB9TMC

  • Software defined lighning detector?

    kaklikkaklik

    Hello everyone,

    I now came across this thread while researching for my dissertation and felt compelled to chime in, as I find this idea of a software-defined lightning detector very promising.

    Introduction

    The concept of upgrading the current lightning detection systems to align with today's technology levels is both timely and required. Compared to the limitations of existing systems like Blitzortung (or many other commercial networks), the innovation potential with the use of SDR is immense.

    The current approach taken by most lightning networks focuses on processing individual impulses. However, I believe the future lies in processing signal fragments. The minimum length of these signal fragments should be 500ms or more, with a bandwidth of at least a few hundred kHz. This approach offers a more physically and scientifically relevant description of lightning. I tried to explain that necessarily in my article: https://amt.copernicus.org/articles/16/547/2023/

    Implementation

    From my perspective, the challenge of localizing lightning strikes is not very hard. I've prepared a relatively simple notebook that demonstrates how to localize lightning strikes from signal fragments: https://github.com/ODZ-UJF-AV-CR/CRREAT_cars/blob/master/VLF_lightning/VLF_location.ipynb The real challenge lies in how to present the results in a relevant manner on the map and to implement a scalable solution.

    Given today's computational power, it's sensible to design the calculations for GPU processing, as this problem is highly parallelizable. With up to 1,000,000 signals per day, data compression becomes crucial to reduce data flow and improve response times, as the bottleneck is likely to be data transfer speed, not computational power in the case of worldwide deployment.

    Conclusion

    Based on my research from a few past years, I fully support this idea of a software-defined lightning detector. The focus should be on processing signal fragments with an appropriate length corresponding to lightning duration and bandwidth and leveraging GPU processing for scalability.

    The next step is to check the possibility of extracting the signal fragments from KiwiSDR receiver stations. The fragments need to be generated at the station side from the circle buffer, based on a trigger (e.g. energy of signal - pulse width and length). That is needed because the required signal fragment bandwidth is very likely to be wider than the usual data transfer speed from the receiver.

    HB9TMCNate_R