G8JNJ
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Some of the 5GHz link kit I've had problems with in the past used Power Over Ethernet which was very noisy. In fact any POE kit seems to generate a lot of unwanted noise. This is a major issue with my Kernow KiWi http://kernow.hopto.org:8073/ which …
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"The antenna switch extension would have to be modified to parse URL parameters like some of the other extensions provide. I don't believe it does this presently." I emailed Kari in August last year to ask about this as a possible enhance…
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The ground spike and ferrites method is certainly better than just using ferrites alone. But I think you may need more turns through the ferrite, or more ferrite, to get the best performance on the LF bands. Steve, G3TXQ's (SK) website gives good …
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Be careful regarding some of the commercial active splitters. Their IMD performance is not that good as they often use MMIC chips that can only achieve modest performance. For example the Elad unit specifies an output IP3 of >24dBm, which is not…
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It looks a bit like the RFI I get from my Solar PV installation which has an LF component and also spikes around 20MHz. Does it vary during the day / night ? Regards, Martin - G8JNJ
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I'm running the KiWi WSPR extension on two of mine at different locations Southwest UK WEB SDR reporting as G8JNJ/2 and Kernow reporting as G8JNJ/3 Using these frequencies 137.50 kHz 475.70 kHz 1838.10 kHz 3570.10 kHz 3594.10 kHz 28126.10 kHz Re…
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I use WinSCP for this sort of thing, it makes it very easy. https://winscp.net/eng/index.php Regards, Martin - G8JNJ
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@Powernumpty If you are repairing the Beagle board, be sure to also check R136 on the PCB underside of the Ethernet socket. The whole sorry saga is told in the thread that this post form part of. http://forum.kiwisdr.com/discussion/comment/5531…
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Raised a similar problem back in 2017 "I have a particular problem in that a lot of Dutch music pirates use my SDR all day long to monitor their own transmissions around 6MHz. What I really need to be able to do is to be able lock out cert…
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This web page provides a chart for winding choking Baluns http://karinya.net/g3txq/chokes/ Regards, Martin - G8JNJ
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Hi John, Yep that fixed it, thanks for sorting it out so quickly. Regards, Martin - G8JNJ
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> >placing the included GPS module with the Kiwi kit on a 12x12 piece of magnetic sheet metal significantly increases the sensitivity of the >GPS module. > I recently repaired a GPS 'Mushroom' antenna. It used the same basic 'Puck' an…
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There is also Marco's map with S/N ratings grouped by bands. http://sibamanna.duckdns.org/sdr_map.html It's not 100% accurate as some types of interference can be interpreted as genuine signals, but it does give some guidance. The http://rx.linkf…
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I found some notes on the subject of "New squelch algorithm for the WebSDR" on Pieter, PA3FWM's website - he uses this on his University of Twente WEB SDR http://websdr.ewi.utwente.nl:8901/ http://www.pa3fwm.nl/technotes/tn16e.html http…
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Hi Nick, I would still be tempted to put a series resistor in-line with the logic input pins (unless the switches already have some) as Clint has already suggested. The GPIO pins can only provide a small amount of current and the danger is that if…
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The key words to search for are VAD (Voice Activity Detection) http://blog.shriphani.com/2015/11/14/voice-activity-detection-in-python-and-swig/ https://dsp.stackexchange.com/questions/2386/libraries-for-voice-activity-detection-not-speech-recogni…
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Hi Christoph, Let me know if you want me to connect the 1PPS RF marker to my spare KiWi. Also does John's new 20KHz Bandwidth modification upset the IQ stream when used for TDoA purposes ? Regards, Martin - G8JNJ
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Hi, I use a pair of back to back IN4148 diodes connected in parallel with the RF input to my KiWi SDR. This limits the RF input to about +10dBm which mode receivers can withstand. As long as the diodes are connected across a low impedance termin…
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> >has anyone attempted to use their PC soundcard microphone input connected to their antenna > Yes I have tried receiving several VLF stations using just a PC soundcard. There is a some very simple receiver software, primarily designed f…
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> >I think it would be helpful if Kiwi operators who have a public presence and are able to do it would put this sort of information on their >splash page. Doing so would allow absolute calibration of a given signal (in whatever antenna is …
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Here's a close up of the MF band filtering. (Image) Marker lines 3 & 4 show the limits of the MW BC band in Europe. Regards, Martin - G8JNJ
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Hi Glen, I note that that you get a peak at around 20MHz. You have a 330pF in place of 100pF (C2). The peak should be at around 30MHz to reduce the loss on 10m and roll off slightly above it. This is an actual sweep of the circuit as built. (Im…
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Hi Alain, This circuit may help. It is placed on the KiWi RF input and rolls off the gain at MF and also incorporates a simple MF BC band notch. (Image) The items marked 1 & 2 are the 50 Ohm input and output ports (treat them as coax connec…
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I have used a Bridge VAP11G-300 Ethernet to WiFi adaptor with one KiWi so that I could connect to a 4G MiFi unit. I also had to use the KiWi reverse proxy service to get around the mobile network Carrier-grade NAT (CGN) Bit of a struggle to get it …
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Hi Alain, I think it could be interference from a data over powerline adaptor. Take a look at the spectrum used by this device. (Image) https://www.nikktech.com/main/articles/peripherals/network/powerline-adapters/6854-avm-fritz-powerline-1240e-…
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Hi Giulio, That is a problem for you. I don't think the simple band pass filters would help in that situation as they probably wouldn't provide enough stop band attenuation. You would need to use filters with a much better defined cut-off of the t…
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Hi Giulio, Happy Christmas. The switched band pass filter seems to be very similar to that found in many 1970 onwards Superhet design based Amateur radio transceivers, so I would expect that (as John has already stated) if you drive the switching …
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> It is not uncommon to get 5 or 10 decodes from a particular station in a row, and then that is it Hi Chris, Ah OK understood. I've also noticed this when DXing NDB's. I think scanning would probably capture most, but I guess that's not good …
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Hi Chris, Maybe I'm missing the point, but I've taken a look at your http://www.blackcatsystems.com/software/dgps_decoding_software_sdr.html webpage. I initially thought you were using the data to provide a high accuracy position fix or GPS correct…
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Hi All, It strikes me that using the same methodology for FT that has already been applied to WSPR monitoring would be the most sensible solution i.e. "no point in reinventing the wheel" The commonality would then allow any changes or e…