n6gn
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Comments
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I think many of us find the low end not dark enough and routinely adjust it to dark blue. jks has mentioned this too, I think.
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Am I using v1.357 wrongly? I can set the value from the admin config tab but it doesn't seem to stick even after restarting the server. For most of what I do I like to have pretty sensitive OV indication and want to turn the default restart conditi…
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I doubt it. I'd expect IMD but not likely to have zero output. It sounds like a connector or misloaded board problem.
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I agree that ham bands should not have been significantly affected if the particular filter you have is making its specification. Does everything appear normal with connectors and the filter itself? Does it measure continuity through the center pin…
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A kiwi installation with an LF/MF line fundamental and a lot of big carriers scores high even though it's a terrible system. I've chosen to ignore the whole metric. As Jim says "it's not very good". I'm not sure how to make it better eithe…
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That's an extension of the problem with publicly available antenna switching. I'm not sure what is desired and I bet there's more than one answer. I guess the generic answer is let the user configure his/her own channel but with a single ADC that i…
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all 1's from the amplitude decode here in Fort Collins. Phase works great.
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It sounds like a modification to the antenna switch extension that passes an offset into the kiwi proper. I bet it can be done, don't know how hard to implement.
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Thanks for the reference. Unfortunately I'm not finding much/any detail about IMD performance. He mentions the problem but spends the article talking about winding and core loss with system level measurement which tends to cloud things a bit for me.…
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Could you elaborate on "Mini-Circuits parts"? Specifically, have you seen IMD issues from their transformers that were large enough in typical antenna environments to be a problem? I have looked and thus far have seen no evidence of this…
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I agree that buying from DXE is the high-priced route and I wasn't pushing back against rolling a board, just saying that simply making a board with isolating RJ45's is not necessarily a solution. You may very likely find that the problem is rel…
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See the previous discussion of DX Engineering filters Even though the CM rejection of a stock kiwi/BB LAN interface isn't bad, it's not enough to prevent typical noise currents (often a family of spectra with ~60 kHz spacing up in 20-30 MHz region)…
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Based on half a dozen Kiwis, I think the "-16" 'factory' number is pretty close. I don't recommend setting it to 'match' the Yaeasu or another radio because, as Martin says, that radio and many/most others are likely only correct at one …
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Clint, I'm not sure about the actual vs. ITU at the low end. I know that ITU seems 10 dB high at 20 MHz, per University of New Mexico LWA measurements and others (even KPH) but I don't know about the LF end except that it seems pretty easy to get pa…
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Thanks John for the repair and also for the explanation. That fixed it. I remember the precision change that got us rock-solid displays but I couldn't see how the clock could be good with the receiver slipping.I didn't know about the two-part setti…
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Be aware that if the input is not terminated, a large signal anywhere in the spectrum can exercise the top bit or two of the ADC and will typically increase the numbers shown a couple of dB or more due to ADC imperfections. The spectrum display is…
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Sure. The buck converter efficiency is very high, I use them on multiple kiwis to power both the kiwi and in some cases a GPSDO as well. Getting a really accurate value requires more careful measurement than I am set up to easily measure but I think…
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Be very careful with the Mini-Circuits T1-6+. It's not really a classic flux-coupled transformer so much as a transmission-line transformer. This means that the CM rejection depends greatly on getting the sense of the windings correct. Inter-windin…
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A single LiPo battery can power a kiwi+Wifi+active antenna for hours> The whole unit is self contained so no CM noise from feed line is possible. (Image) Since this is really only for testing, to see what your noise situation with no transmis…
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Since I don't know the correlation between the kiwi measurement (~-140 dBm/1-Hz at 20 MHz) and e-field for your "200 m distant, empty field" measurement, nor do I know whether there is transmission line or other CM noise going through the…
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Ulli, I agree that it is difficult to get all the way to an absolute reference but I think it worth the effort. You say: "I don't even think ITU recommendation has any value any more by today, as noise levels increased in most residential QTHs…
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(only a comment about broadband match). It's not the *measured* antenna impedance that goes into the calculation but rather the radiation resistance and how it is coupled to system. A 1 mm monopole connected to a 50 ohm load is matched LF-HF pret…
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Antenna factor for a small antenna changes at 20 dB/decade so a single value is only correct at one frequency. On top of that, the additional mismatch to the preamp is frequency dependent and should be modeled. Circuit simulators can do this well a…
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Clint reminds of another point. If you use merged receivers DO NOT change the name from "MERGED_RX..." because that name is somehow hardcoded. The suffix may change thus MERGED_RX_SYS1 is OK but make sure the MERGED_RX part precedes it…
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Martin, At the risk of confusing things more, the following values for one kiwi from my WD.conf seem to work (doesn't mean the values themselves are meaningful though!) " ... DEFAULT:-6.0,2200:-6.0,630:-6.0,160:-6.0,80:-7.0,40:-7.5,30:-8.0,…
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WD does not allow moving the reference plane as far as the antenna. Alone, the kiwi with a -16 calibration factor is pretty accurate, within a dB at 14 MHz. It reads high above that and low below. With WD's correction that frequency un-flatness is…
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https://github.com/jks-prv/kiwiclient/tree/master/tools but Rob and all need to explain broadly where things are found. I'm not at all sure the latest versions are here. Rob?
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Ulli, A great many things to be said about what you wrote, perhaps too much and annoying to this forum. Let me just say a couple of things. For constant ERP from a distant source, available power follows a perfectly-matched antenna's aperture. At…
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Measuring it when you can is great but even with a crude (optimistic model) you can see the general problem. It's not possible to match to the radiation resistance of a monopole far from resonance, this means that there is effectively (room temperat…
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As a first approximation, presume that the ground losses are zero. This isn't quite correct but other issues are bigger, mainly mismatch loss at most frequencies for a 6m vertical radiator. Its 'radiation resistance' only rotates to a good match (~…