G8JNJ
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Hi Jimmy, I was intrigued by your passive whip antenna, the ApexRadio 303WA-2. I did a bit of research online and managed to find some notes regarding its construction. It is basically a 1.7m long whip, connected to a 64:1 ratio broadband Unun trans…
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Thanks for the SNR update, that will be very useful for testing. Regards, Martin
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Hi Ben, Thanks for this, but for some reason I don't seem to have received your PM. If you have a look at the recent antenna thread, you can see a photo of some of my antennas. https://forum.kiwisdr.com/index.php?p=/discussion/3106/antenna-recommen…
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Whatever you use, it is likely to have to be a bit of a compromise. Active monopole / E-Probe - Very small and easy to hide, good performance from VLF to 30MHz + Omni-directional. Being an unbalanced high impedance antenna, it is very prone to noise…
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The pins on http://rx.linkfanel.net/ move around when you refresh the browser. Apart from randomisation, I think it is to ensure that all the pins are at least visible at some point in time, and not masked by others. https://forum.kiwisdr.com/uploa…
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Agreed, the latest enhancements make it so much easier to find KiWi's with decent reception of the target transmitter. Thanks again John for all of your hard work. Regards, Martin
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I just checked with my KiWi V1 & V2, which are both fed from the same external GPS antenna using an active splitter. The performance is pretty much identical, but the system noise figure and sensitivity in this case is being defined by the GPS a…
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Ah, that's why I didn't have any problems, as I've yet to bite the bullet and upgrade to Debian 11. I think I wait a while longer if problems like this occur, especially if something this basic is missing. However, I'm pleased that you managed to re…
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Hi Nate, I don't know why you are experiencing this problem. Background autorun doesn't have any effect on the image being displayed. Could it be a problem with your image editor od choice appending the file with something that the KiWi doesn't lik…
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Hi John, Great, thank you. JSON is fine. My thinking is that it may be possible to use this to drive some form of external AGC, or at least be able to post when the majority of ADC overloads occur. Regards, Martin
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Hi John, Could that also return the existing count before it was reset ? That would save having to view different sets of stats, and be handy for a quick automation process. Regards, Martin
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I'm assuming the problem is due to direct sunlight on the black GPS puck, causing it to overheat. Can you shade the antenna in some way, with a material that will not block the GPS signals ? Regards, Martin
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Hi Bob, Your guy is actually a bit thinner than I expected. The cores I suggested will accept 1" diameter, and they split in half and clip back together. So you can easily clip one over a guy, and let it rest against a turnbuckle or whatever, t…
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Hi Bob, OK all good. I was thinking that you could perhaps make a coupler, to fit over the steel guy rope. Something like a big Fair-Rite split ferrite core. https://fair-rite.com/product/round-cable-snap-its-431177081/ https://fair-rite.com/product…
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Hi John, Thanks for the explanations. I'll try to remember that I have already mentioned these, to save troubling you with them again. Regards, Martin
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Hi John, Thanks for the TDoA waterfall enhancement, it is a very useful enhancement. There are a few slight issues I have noticed during use, but they may have been present for some time. ----- When there are several KiWi's on the same site, it is q…
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Hi Glenn, The type I referred to are the low'ish' cost units available for the amateur market, and these tend to use narrowband tuned circuits or R/C networks in order to provide the required variable phase shift networks. But I do agree with you, i…
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Hi Ben, Yes, I'd like to have a look at that if possible. I've currently got problems with my VHF/UHF OpenWebRX sdr's at the Wessex site. The signal levels are fading up and down at random intervals, and I'm trying to figure out the likely cause. I …
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Hi John, That's a good idea for the TDoA selection and would certainly help. I wonder if it would be possible to perform some other quick comparison to validate if the selected KiWi's are actually receiving the target signal. I often find when I per…
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Hi Ben, It's an interesting idea. I wonder if something like CatSync could be modified to do something like this. Maybe contact Oscar, DJ0MY ? Regards, Martin
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My sincere thanks you yourself and Christoph for fixing the TDoA issue. The audio quality is now much better too. The severe audio intermodulation, problem, which was very apparent when listening to NBFM signals with a 3kHz deviation CTCSS tone has …
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Hi Bob, Are the tower anchors conductive steel or insulated kevlar type stuff ? Regards, Martin
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Just checked mine with a signal generator and CW setting on the KiWi, and it is reading correctly at frequencies >10MHz, but it does vary slightly across the whole range. The worst case being 2dB low at 1MHz. I'm using an S-Meter calibration of …
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Hi, Yes, I have used them too, but unfortunately on this occasion it doesn't seem to be low frequency common mode noise that can be mitigated with galvanic isolation. It's something odd being emitted from the RF input stage, as I can see it on the s…
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After a very chilly site visit and a lot of messing around, I have found (but not cured) the low frequency 14 second noise / loss of sensitivity problem at Wessex. It seems to be noise being introduced by one of the other SDR's on site (OpenWebRX &a…
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Hi All, Thanks for all your contributions, but I just wish to emphasise this is NOT a problem with the KiWi's, either V1 or V2. It is something in, or close to, the Wessex hilltop site that is causing these strange effects. Earlier today it was much…
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Yes it is very odd, but it must be something on the site. It only affects the signal level and noise floor on frequencies below a few hundred kHz. My suspicion is either the ultrasonic pest repellers or the electricity smart meter, but I added hard …
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To get back to the updates. I also very much like the additional dBm resolution and the orange 'Attenuation' indicator. Thanks, Martin
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Hi John, I have remotely experimented with the sdr's at Wessex, with no obvious conclusions. The antenna and distribution amplifier are not the problem. I have turned off as many individual items of equipment as possible, and the problem (although s…
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Hi John, Thanks for spotting that, it's all very odd. At first I thought the 1 second gain reduction every 14 seconds could have been an antenna fault, as it us very wet and windy over here, so I switched over to the reserve, and it is still occurri…