G8JNJ
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Hi Jari, I suspect that when the 0V indicator is operating, the ADC will be overloaded to clipping point and will have 'run out of bits', so the dBm value will no longer be valid. Regards, Martin - G8JNJ
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Fortunately the KiWi is a good diagnostic tool that can quickly help you find noise sources. Try the setup without an antenna connected - do you still see the noise on the waterfall / spectrum display ? If so the power supply is most likely to be t…
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Is it possible to extract GPS co-ordinates along with the signal strength value ? I'm thinking that it could be used as a drive by measurement system, and used to produce heat maps. An example of what I'd like to achieve is shown on this web page.…
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I think as long as you can discover the initial IP address of the KiWi when it's connected to the network, then you should be able to do everything else via a web browser on the tablet. You can do this by reading and decoding the flashing blue LED'…
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Hi John, OK that sounds EXTREMELY promising. My thoughts were that it could be used for a few purposes. 1. Used as a frequency reference to lock external transvertors / convertors to the KiWi. Especially if folks are now getting interested in pos…
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If you have a genuine flat gain amplifier ahead of the KiWi you could modify the calibration. But you really need to calibrate both antenna and amplifier together. The loop response is not flat, but over a small frequency range you may be able to …
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No, I just checked the KiWi to make sure it was reasonably close to the dBm calibration. I'm not sure how you would calibrate for an antenna. Antennas used for measurement purposes generally have a calibration curve showing the Antenna Factor (AF)…
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Hi John, This is an interesting addition. Is there any way the signal generator output could be routed to the outside world, for example on one of the GPIO pins, or by means of a hardware hack ? Regards, Martin - G8JNJ
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I checked Kernow with a signal generator before shipping it to site and ended up with these settings:- S-meter calibration (dB) -16 Waterfall calibration (dB) -15 However in most cases I don't think you can rely upon the off-air readings as every…
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Hi Lonecrow, If they are fairly short patch cables it won't make much practical difference. Ideally you would use the correct impedance throughout, but it's less critical for receive only purposes. Note that frequencies on the airband commonly ha…
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Hi Lonecrow, Yes you can use the airband and FM band filters together, if the airband filter is good enough you may not need the FM band notch. I think the reason you don't see it with the dongle and SDR Sharp may be an issue with the KiWi that yo…
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Hi Lonecrow, I think the problem could be a very strong out of band VHF Digital TV signal that is being down-converted to a frequency that is being aliased by the KiWi to the frequency range you are seeing. The reason for trying the Airband filter…
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Hi Lonecrow, Looking at the spectrum and using the new peak hold function, the noise has a fairly well defined 'shape' that could possibly be a VHF Digital TV transmission using the ATSC standard. I have a theory about how this could be occurring,…
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Hi John, Ha yes - Well it's your party :-) But, if you don't ask you don't get, and if you always ask you sometimes get ....... Thanks again for all your hard work and consideration. Regards, Martin - G8JNJ
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Hi John, Understood. Yes I also find listening to most broadcast stations fatiguing. Too much processing and the ongoing obsession with 'loudness wars' (mainly between local broadcast stations competing for their market share) which really shou…
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Hi Glen, I absolutely agree with you, I also don't wish to burden John, as he has got enough on his plate. You are probably correct that something like kiwirecorder is the way to implement some of these ideas. Maybe I should 'bite the bullet' and …
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OK John, I'll feed this back and see if I can get more info. Regards, Martin - G8JNJ
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Hi All, The 50uS & 75uS pre-emphasis characteristic curves are broadcast standards. Amateur radio and Citizens Band NBFM uses a 6dB per octave curve usually applied between 300 - 3000Hz. This came about because early NBFM transmitters tended…
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Hi John, Is it possible to add any defined url switches / extensions that were present if the browser session was opened with them, to the green 'copy to clipboard' button in addition to the standard frequency and mode etc. ? Or maybe all the curr…
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Hi John, Brilliant :) Makes spotting and determining the amplitude of fleeting signals much much easier. (Image) Thanks for this (and all the other stuff too). Regards, Martin - G8JNJ
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Hi John, That's a very useful improvement, so thanks for that :-) The MMA & EMA filters work the best for me with SP settings of around 5. Any chance of adding peak hold 'outline', something like this in SDR Console V3 (Image) Regards, Ma…
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OK I have sent you an email, Regards, Martin - G8JNJ
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Hi Mike, I operate the Kernow KiWi SDR and I'm embarrassed to say that the antenna it is using isn't that good, as it's currently picking up a lot of noise from equipment in the building it is sitting on. I hope to fix it at some stage, but I live…
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Hi John, Thanks for fixing it. I only accidentally noticed it when I realised that the auto notch was no longer removing a strong carrier. Regards, Martin - G8JNJ
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" My remote location is on a 3G network" You may also need to find a way to deal with Carrier Grade NAT (CGN) which means that you won't have a defined public IP address. I had to use the KiwiSDR reverse proxy service provided by John in…
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Hi, I took a quick listen the cyclic raspy noise reminded me of a mobility scooter charger that I can hear from housing in the village near me. So it could be something similar. Here's info on a drive by system I made to try and ID VDSL sources. …
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Hi Glen, Can you clarify a point. In a single DXE filter unit, are there two of the "circuit F" filters (that you showed in your post) connected back to back or does each unit only use one of them ? How are the ground connections handled…
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In old Fax machines the image was placed on a drum which rotated as the image was scanned. Most HF Faxes are scanned with a standard drum speed of 120rpm. The Japanese pages are scanned at half of this speed 60rpm, possibly because of the structure…
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Does the KiWI GPS antenna work OK with your other GPS receiver ? Is the KiWi GPS antenna placed on a metal surface ? This helps because the antenna was designed to sit on a motor vehicle roof which acts as a ground plane / reflector. It doesn't wor…
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Hi Ron, From memory you won't get clean faxes from the Japanese stations who are using 60rpm with the KiWi decoder, but I believe they transmit English news at 19:00 utc using 120rpm which looks good. Regards, Martin - G8JNJ