London Shortwave

Shortwave Radio Enthusiast based in London, UK. AirSpy+SpyVerter, FCDPro+, Lowe HF/PR-150, Tecsun PL680, DX Engineering NCC1, two Wellbrooks 1530S+, EN/RU/ES

London Shortwave boosted:
2025-01-28

Not bad at 80m, with an indoor 3m-circumference amplified loop (with some lightning thrown in this morning for good measure!)

Period was local sunset to sunrise, 27/01/2025, quiet (Kp 1 or less) geomagnetic conditions. RX mode FT8

2025-01-25

Thinking of putting up my Twitter archive online somewhere, now that I've officially closed that account. Unfortunately the archive is missing replies from other users and all the other interactions but it's a vault with many good memories of doing radio in the field.

London Shortwave boosted:
2025-01-02

Looking Back at 2024 and Ahead to 2025: A Fresh Start with Correspondence

Good Morning! It’s January 1st, 2025, and I’d like to wish you all a very Happy New Year! As I mentioned on Patreon yesterday, in many ways, I’m happy to see 2024 in the rear-view mirror. It was a challenging year for our family, but even amidst the difficulties, there were countless moments of joy and celebration. Our biggest takeaway from 2024 was experiencing the overwhelming love, kindness,…

swling.com/blog/2025/01/lookin

2024-12-15

🇰🇷 News bulletin in Korean reporting on MPs voting to impeach President Yoon Suk Yeol. Recorded outdoors on 9740kHz in London, UK on 13/12/24 at 1600 UTC with the Pi Zero 2W recorder, AirSpy HF+ Discovery and Wellbrook UMB130 balun / 2x6m dipole

youtube.com/watch?v=PqY2BgOz4j

2024-12-15

Had a great time capturing the 31 meter band for 3 hours this afternoon using my Pi Zero 2W portable recording contraption and AirSpy HF+ Discovery with the new firmware. Flawless baseband AGC despite a very hot antenna (2x6m dipole) AND the HF preamp being on. #PortableSDR #SDR #Shortwave📡

2024-12-12

The PiZero 2W spectrum recorder runs for 7 hours on two 18650s & a step-down 5V converter (which doesn’t seem to add measurable noise on HF). And of course the batteries are hot-swappable as the unit has its own small UPS battery. The only limitation is the amount of free space on the MicroSD card 📡#PortableSDR #SDR #HF #Shortwave #SpectrumCapture #SpectrumRecording #AirSpy

This image shows my portable spectrum capture recorder based on a Pi Zero 2W that I have mentioned in my previous posts. It is connected to an AirSpy HF+ Discovery, which is in turn connected to a 2x6m dipole mounted over a big tree. It is externally powered by two 18650 LiIon batteries and a 5V step down converter.
2024-12-07

🇮🇳 I miss having All India Radio's English language service in abundance on shortwave! This is a recording from 17/08/2015 at 1900z on 11670 kHz, received indoors using a FunCube Pro+ dongle and a Wellbrook ALA1530SP loop antenna. #Shortwave #SDR #SpectrumCapture #AllIndiaRadio #RadioArchives

2024-12-06

@w8emv oh damn! I haven't tried to tune into their signals recently myself but I imagine they're outputting at much lower power these days because of the ongoing difficulties with their power grid.

2024-12-06

🇨🇺 I've been digging through my old archives and my very first spectrum recordings. Here's Radio Habana Cuba's broadcast on Fidel Castro's 89th birthday (11670kHz - 06/08/2015 0101z). I captured this indoors with a Wellbrook ALA1530-SP antenna and FunCube Dongle Pro+. #Shortwave #SDR #SpectrumCapture

2024-12-05

🇧🇷 Rádio Nacional da Amazônia on 04/12/24 at 2200z on 11780 kHz. Captured with the battery-powered Pi Zero 2W, AirSpy HF+ and 2x6m dipole in a local park. #PortableSDR #SpectrumCapture #Shortwave #HF #DX #AirSpy #PiZero2W #PiZero

2024-12-03

@w8emv thanks Ed, that’s super useful and definitely worth a try! 73s!

2024-12-03

4/4 After a few charge and discharge cycles, the 4xAA Eneloops support the built-in battery for longer: the recorder kept going for 4 hours and 10 minutes. That's long enough for most of my park outings! Here's the resulting capture from last night. The system is good to go! 🚀

In the next version I will add a settings page where you'll be able to change the capture bandwidth, switch wifi on and off (to conserve more power) and to shut the recorder down gracefully. 👨‍💻

2024-12-03

3/4 setting the centre frequency and starting the recording:

2024-12-03

2/4 Just playing around with recording some medium wave spectrum off my YouLoop installation on the balcony. Testing power-on and boot-up:

2024-12-03

1/4 Final version of the UI (for now). Battery indicator, remaining recording time available & the duration of the current recording (in hh:mm). The Pi boots into this UI and triggers airspyhf_rx to record with the selected parameters if a HF+ is connected. The screen has minimal 🔋 impact when sleeping.

#SDR #HF #Shortwave #SpectrumRecording #PortableSDR #Mediumwave

This image shows a Raspberry Pi Zero 2W with a LiPo battery powered UPS bottom HAT and a TFT screen + joystick + two button HAT attached on top. The screen is showing the UI described in the post.
2024-11-30

4/4 Experimenting with a new physical interface for the spectrum recorder. Added an option to switch off the backlight to save battery (& when I send the UI to “sleep” this way, I also change the controller polling interval from 0.1s to 1s to reduce Python’s CPU usage). These things matter on Pi Zero 2W

2024-11-30

3/4 Here’s a recording I made in my local park last Friday. New Zealand was coming in nicely! The baseband file is saved onto the same microSD card that the Pi boots from, so the card has to be fast and preferably class A2 for more efficient random writes (the OS keeps interrupting sequential I/O).

2024-11-30

2/4 Currently there’s no physical UI so I trigger airspyhf_rx by SSHing into the Pi via wifi from my iPhone. A few years ago
@lambdaprog.bsky.social suggested modifications to the code that enabled baseband recordings to be made in raw file format that could be opened in SDR#. I ported them over.

This image is a screenshot of an SSH app running on my terminal. It shows me issuing a ./record.sh command that triggers airspyhf_rx command line utility that captures the SDR’s output to a local file on Pi’s microSD card. It uses the centre frequency that I specify to the record.sh she’ll script.
2024-11-30

{Cross post from londonshortwave.bsky.social}

1/4 This is my most portable shortwave spectrum capture contraption yet. A Pi Zero 2W rigged up to an AirSpy HF+ SDR. The Pi has a Waveshare UPS HAT with a small capacity LiPo battery — enough for 70 mins of recording. It is further supported by 4 AA Eneloops, adding 100 mins of extra recording time

London Shortwave boosted:
Ed W8EMV :radio_tower:w8emv@mastodon.radio
2024-02-04

Decoding Morse code from the first ham radio station on the moon!

"Trying to decode LEV-1" by Daniel Estévez #EA4GPZ / #M0HXM

edit: cc @destevez

destevez.net/2024/01/trying-to

Post includes a GNU Radio flow graph with a decoder and a Jupyter notebook, plus a detective story on how to recognize and decode undocumented codes.

"the transmission is CQ CQ DE JS1YMG" followed by "a lot of hexadecimal data" presumably telemetry

"the signal from LEV-1 is quite peculiar"

#lev1 #gnuradio #js1ymg

Client Info

Server: https://mastodon.social
Version: 2025.04
Repository: https://github.com/cyevgeniy/lmst