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ka9q
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If you're taking suggestions, here goes... I can't find anyone else doing automatic AGC thresholding, so I think it's novel. (No, I'm not going to try to patent it. But I'd like to get it out there to keep anyone else from doing so). I think it work…
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Thanks for that document, looks pretty good! His AGC section mentions two recovery rates, fast and slow. But I can't find any controls in the web interface that would select this.
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I'm only looking at the interactive controls.
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I can see Radio Romania International's DRM signal on 7220 kHz on my waterfall (0507 UTC) but it's much too weak to decode. (This is par for the course here in San Diego. Only occasionally can I decode any DRM signals, though a few are often visible…
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I got my unit working again by simply loading the new image from the micro SD card. I saved and restored the kiwi.config directory by using rsync to stash it on a local machine, then copying it back when I had the new image running. That was a lot f…
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By "bricked it" I meant that it didn't reboot. I'm sure that it'll come back when I write a new image on a flash card. I already backed up my kiwi.config directory so I'm covered there. It's just a lot more work than it should be. Sigh. St…
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I ended up bricking my unit. Oh well. Updates really need to be easier. It's linux; why can't it just be "apt update; apt upgrade"?
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Could you post the current contents of /etc/apt/sources.list to make sure I have them right?
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I managed to upgrade to buster without using a micro SD card, simply by editing /etc/apt/sources.list and using apt. There were a few nits along the way but it seems to have upgraded and is running kiwid again. Haven't rebooted yet though.
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I'm still not seeing any attacks on the new port number despite being listed in kiwisdr.com/public for several days. The attacks still persist on the old port number, however. Instead of using iptables to simply drop incoming packets, I'm sending th…
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Kramcd, yes, those are the same addresses I have been seeing. The "Piscataway NJ" location comes from the application; the addresses themselves are all over the place. Has this sort of thing been going on for a long time? What are they tr…
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Good to know. I was wondering about that, and with the forum down I was beginning to suspect the worst...
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I too have been seeing coordinated, sustained attacks, but on only one of my Kiwis, and the addresses were NOT in the 34/8 or 35/8 ranges. They appeared to be a poorly programmed bot that tried to keep all channels busy. The user claimed to be in Pi…
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You can get more progress messages when running update_fix by issuing the command sh -x ./update_fix rather than just ./update_fix This invokes the shell with the -x option, which shows each command in the script as it is being executed. I also had…
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Glenn, my configuration is too complicated to easily describe here, but I did try several simple experiments. First, I disconnected the GPS antenna from the KiwiSDR. The noise < 30-40 kHz actually went UP. (This connector comes from an HP GPS ant…
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Hi Glenn, long time no hear! Wow, that's a really useful writeup that gives me a lot to chew on. I'd been off HF for a long time but returned to it in my retirement. Physics hasn't changed, but everything else has. There's been an explosion in digit…
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Do you overlap windows? I'm a big fan of the Kaiser window for general purpose filtering, but I know that there are windows optimized specifically for spectral analysis (as opposed to filtering).
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I can see how SMPS harmonics might be shaped by the driving circuit (eg, push-pull vs single ended) but it is indeed hard to understand why they should be so much louder at higher frequencies. Maybe stray capacitance in (or around) the toroidal indu…
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Wow, that was fast! Thanks so much. I might be able to help with that FFT scalloping. Are you using a window ahead of the FFT?
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How many threads or subprocesses does kiwid use? I use them heavily, mainly to take better advantage of ubiquitous multi-core CPUs but also to make bugs and memory leaks easier to isolate and contain. At the very least, a short-lived thread will cle…
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I'm listening to your SDR now but I don't hear it, probably because it's too late (0108 UTC). In fact you have a remarkably quiet QTH compared to mine (San Diego CA DM12ju). But your description sounds remarkably like one source of QRM I'm working o…
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If your goal is to check that the transmitter isn't splattering, why not just look directly at the modulated spectrum? Depending on the transmitter design, you could have more than 100% negative modulation and still not have splatter. One way is to…
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Thanks much! A loop BW of 200 Hz does seem rather wide for AM on HF. If the loop gain or damping factor depend on signal strength, as they often do, it can also be upset by low frequency modulation components.
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Yes, though the degree to which these internal DC-DC converters actually cause interference on HF depends on how much of that switching noise is conducted to the outside world. One of the biggest offenders in my shack is an external powered USB 3.0 …
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Thanks for the details. It's just a fact of life that the closer a modulation/coding scheme gets to the theoretical limit, the more "brittle" it must become. That's why so many digital schemes either work perfectly or not at all. Even anal…
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So what transmitting stations still exist in North America, even if they're not operating?
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I concur with the suggestion to try another power supply. They can vary enormously in noise generation. I've been switching to Cat 7 ethernet cables where possible. Each pair is shielded, and the entire cable has an end-to-end shield that connects …
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Wow, I thought all the transmitting stations had been demolished.
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The most important factor is the choice of modulation; the higher order constellations (especially 64QAM) require a much higher SNR to decode. In my opinion, many DRM broadcasters are overly optimistic about 64QAM. I rarely decode even a 16QAM signa…
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Are any LORAN-C signals still on the air anywhere in the world? I haven't heard one in over 10 years, since the US shut down its system in 2009 or so.