@ea4eoz

Mostly ham radio, electronics, programming, microprocessors, radiation and (radio) astronomy

 Spain
ea4eoz.blogspot.com/
Joined December 2013
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401Media
The 10-hour blackout in Spain confirmed that switching power supplies have destroyed amateur radio. 10 hours of noise-free bands and extremely weak signals with crystal-clear audio. Just incredible! But everything went to hell when the power came back on.
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Most USB-C headphones have a miniature USB sound card in the connector
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Another thing you can do with the SDR capabilities in ESP32 chips is to compare antenas. Left: PCB antenna. Right: Ceramic chip antenna. Same settings both sides. Yes, ceramic chip antennas are truly terrible.
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After playing a bit with the ESP32 SDR capabilities I noticed the ESP32 variant is really important because it determines the SDR capabilities. For example, a ESP32-C6 tunes easily from 2148 to 2900 MHz (+/- temp) but the original ESP32 is much limited
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Of course all those discrete frequencies are WiFi channels 3 to 14. Channels 1 and 2 are inside the fine tuning range. So for future ham radio applications around 2.32 GHz not every ESP32 will work.
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Now I wonder why the original ESP32 can do fine tuning at the beginning of the ISM band... maybe some obscure feature we have missed?
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Testing 15 Euros ESP32 : 80Mhz wide spectrum on 2.4Ghz with recent hack : here is DATV and wifi. Next step : getting I/Q and having TX ! A new horizon for cheap sdr : eSpDR.
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Inside a cheap VHF/UHF walkie antenna
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Increible!
Alberto Ortega@ea4ferSep 2
926km en LoRa APRS!!!! Murcia (IM97PR) - Córcega (JN41JS)
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Miguel A. Vallejo retweeted
David Cardeñosa@dcardenosaAug 13
Algunas imagenes de la totalidad del #eclipse desde #boecillo #valladolid
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Pasada total la del skater profesional olímpico y los fotógrafos 🔝🔝🔝
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Miguel A. Vallejo retweeted
David Cardeñosa@dcardenosaAug 4
Haciendo pruebas para el #eclipse he cazado un avión pasando justo por delante del Sol 😎 A las 21:04 CEST desde #boecillo #valladolid
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I've spent last 24 hours on 50 MHz FT-8 with a vertical antenna and IC-705. This are the stations I've received and the ones who received me. Not bad for such small station
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The distance graph calculated by PSKReporter is quite interesting. It shows that Es optimal distance was 1200 km, with a pronounced null at 600 km: too close for Es, too far for tropo. It also shows how the stations cluster around multiples of +/-1200 km. Typical for multihop Es
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This is what a fossil deposit of toroidal inductors looks like
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Today I was reading about the frequency rounding system for the 8.33 kHz step in aeronautics. Whoever came up with that system, please resign and do something else, like gardening, farming, or baking
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Still alive!
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For all these years I believed that root was the all-powerful user who could do anything on the system. Even destroy it. I was wrong. Secure Boot is.
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I've been seeing these signals, barely 3 kHz wide and lasting half a second or less, on various SDRs and across different ham bands for weeks. They appear on random frequencies, and when you manage to hear one, it's clearly a digital signal. Any ideas?
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