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n6gn

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n6gn
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  • It's not true that beam forming and noise cancellation can only work on a narrow band of frequencies. By using a broadband antenna system such as the quadripole I show on my web pages along with a multi-decade quadrature network, also shown there,…
  • That will be great as far as I can tell. All we can ask for is what the user entered as the ext clock frequency. Hopefully the HW is adequately referenced and has provided what he entered. Thanks for doing that.
  • Yes, I wasn't sure that it was clear that we needed to know the ext clock frequency as well as its presence. Thanks John.
  • Is there a chance of having an output on the status page that allows access to the present ext_clock frequency added to status? It seems that among ext_clock, frequency, GPS or not and versions it has become a bit complex. There has become a matr…
  • It's on a remote with v1.616 and external GNSSDO 66.66 MHz clock. I was attempting to update it but have since thought better of the idea and done some experiments on a similar system here at the QTH, looking at boundary spurs and phase noise. Runn…
    in V1 653 Comment by n6gn January 12
  • OK, didn't know how you used the diff. But that's the end of an attempted update on the console. Nothing more happens, no update and no error other than it didn't update. The local Kiwi updated fine. I can send you the entire console output if it h…
    in V1 653 Comment by n6gn January 11
  • Trying to update both a local and a remote KiwiSDR to 1.653 in order to compare reported frequency of a known OTA FST4W LOS signal to see how much error a 66.66 MHz clock introduces with the newest code. The local seems to be proceeding OK but the …
    in V1 653 Comment by n6gn January 10
  • 1.650 reads-72.8 dBm for my -73 dBm at 14.1 MHz source which is well below the measurement uncertainty of my old S-Meter calibrator. Noise in 10 kHz is similarly very close to expected, but of course noisy. I like the extra displayed resolution.
  • The amplitude reporting, S-meter and dBm field, do seem to be several dB down from previous code. I just checked and found this to be true on both noise and coherent signals so I doubt there's a substantive SNR change.
  • Ah! It hadn't occurred to me that a local user had higher priority than a wide area one and therefore special permissions. This points to either Rob or one his designate admins to having caused the problem. But of course his secret is safe with us,…
  • You can test this yourself by driving across the ends of the PCB from a 50 ohm swept HF source at a known power level. Calculate the current through the ground planes and compare that to the Kiwi's response, which should have a noise floor around -…
  • Every SMA on the antenna end of the rx probably should be isolated and not just for consistency. This is because attaching any of them to the enclosure creates a CM path through the groundplane at that end of the PCB and an attendant IZ drop which …
  • Thanks John. If I can arrange the the timing to have the new subnet up after a reboot but before the BB looks for a network that could work. But if I'm too slow, doesn't the BB just sit with no network at all if the new subnet isn't , having genera…
  • Steve_MWC asks: "Lastly, the transformer is really not operating as a balun. Both sides are unbalanced but isolated. Does anyone actually want to connect a truly balanced input to their KiwiSDR. Perhaps using balanced feedline rather than coax?…
  • The binocularism doesn't make it so but the twisted/paired primary/secondary do. No doubt the mu of the core material is pretty high but perhaps not as high as the -6 version. Probably they've reduced the total length of the winding(s) by changin…
    in KiwiSDR 2 Comment by n6gn August 2023
  • As I recall the T1-1 was spec'd at ~1 pF inter-winding capacitance so I'd expect whatever they are using inside the FTB-1-6 to be 6 dB worse for CM. The T1-1 is in a bigger package and probably has more core material than the ADT1-1. T1-1 (blue) …
  • It might be worth emphasizing that all electrically short/small antennas have the same gain - about .4 dB less than that of a dipole. They have the same pattern and aperture so this must be so. The problem is that the radiation resistance falls as…
    in KiwiSDR 2 Comment by n6gn August 2023
  • Although the specs don't indicate this It appears that the Mini-Circuits '6' series transformers are NOT simply flux coupled. They would seem to use a higher permeability core material to achieve increased low end and twisted pair transmission lin…
    in KiwiSDR 2 Comment by n6gn August 2023
  • I'm coming to this late so maybe I'm missing something you've already tried but it would seem that D3&D4 should definitely be moving around. Maybe they aren't stuck by the ADC (now replaced) output but by the input they are driving? This would …
  • It's also possible to pop the plastic top of the CMC with a thin flat blade screwdriver, cut the winding connections two at each end and jumper lengthwise in place of the disconnected windings. This avoids having to heat up the pads to remove the …
  • I find a measurement of diurnal (propagated) noise variation to be the single best indication of station quality. It's influenced by latitude , MUF and solar cycle but does correlate well with WSPR spotting performance. Looking for a single metric …
  • Have a look at the better WSPR/FST4W reporters to get additional insight into what is working well. http://wspr.rocks/topspotters/ again, not a perfect metric because it's dependent upon geolocation., MUF and latitude,but still very useful. Glenn n6…
  • I suggest being a bit cautious about simply grounding the SMA's, HF antenna and GPS, to the enclosure. In so doing you are creating another shunt path for common mode current through the entire structure, That is, for example, current coming in on …
  • Additionally on the off chance that someone reading this doesn't already use VE3EN's site: https://www.solarham.net/
  • We do indeed have pretty impressive grayline/chordal reports. If you had spectral spreadingvalues for some of those I'd not be surprised to see some exceptionally low values as well. Amazing indeed ! Glenn n6gn
  • "I also suppose this means we should be relieved all the MW/SW broadcasters are not carrier-locked with GPSDOs, for similar reasons.." That's true but their audio peaks are all perfectly aligned and 6 dB bigger than the vector sum of all t…
  • Thanks John, Yes, it seems to have returned to the previous performance. Audio distortion seems low although I may still be hearing something happening at higher deviations (not sure) and I can still hear background sub-audio, 100 Hz in the case of …
  • I'm not current on all the possibilities but FET switches aren't saddled with the junction potential of bipolars and can exhibit very low on resistance. For low cost components, I tend to look at current wireless products, especially mobile phones, …
  • The newer version of the PE4302 31.5 dB step attenuator I've used, the PE4312, is spec'd https://forum.kiwisdr.com/uploads/032/IEUM39EBZ6GE.png I presume things change at LF but they also say: "Covering a 31.5 dB attenuation range in 0.5 dB s…
  • After killing Rx1, rx0 continues to show no drift even after multple reloads.