jks
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- jks
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Important: updated assembly guide (v1.1) for the aluminum enclosure
There is an updated assembly guide (version 1.1) for those of you who have purchased the new aluminum enclosure. Corrections to the parts list, clearer photos and an important note about removing one of the two pieces of sticky tape attached to the fan. Special thanks to Dave, PJ4VHF, from Bonaire for discovering the issue.
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OV Worries
I've explained this somewhere before (it really needs to be a FAQ so people can find it).The current FPGA logic just records an OV event if a single overflow is reported by the ADC. This is nonsense of course. You'll get overflows during normal operation as all those sine wave peaks from strong HF signals just happen to sum up during one ADC sample. That in itself is not a bad thing. You won't hear distortion because of it. Some sort of averaging of the ADC overflow output needs to occur and only when a threshold is exceeded should an OV event occur.And that's really your question: what should the threshold for ADC overflows be before an error indication is given? You could even imagine a a couple of different threshold being shown, done e.g. with colors.
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Wideband pulsing noise & Noise Blanker absence: I'm in trouble! [NB added in v1.152]
1 / 12 kHz = 83 usec. And the NB needs a couple of gate samples to work properly. So going below 100 usec doesn't get you any improvement.Moving the NB to a higher sampling rate in the FPGA is one option. But that will take some effort. Or increasing the audio bandwidth, which has its own problems. -
Direction Finding and linking existing KiwiSDRs
Wow -- check Christoph's latest post: https://github.com/jks-prv/Beagle_SDR_GPS/issues/130#issuecomment-347206064It's a plot of a ground wave TDoA solution for DCF77 using three Kiwis relatively close by.
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Sound recording from multiple opened browse windows for diversity reception?
When you include the --kiwi-wav flag the GPS timestamps will also be added to the files when recording in IQ mode. This will allow post-processing the data for the very interesting projects now ongoing: Christoph's HFDF work and zfyoung's diversity reception.There is code in the repository (proc.m, read_kiwi_iq_wav.cc) for Octave (Matlab) to read the files and create various plots. I haven't tried this myself but see the Github GPS timestamp issue (https://github.com/jks-prv/Beagle_SDR_GPS/issues/130#issuecomment-346085747) for examples.
