Found a cheap batch of the BLK-89-S+ DC Block from #minicircuits - wondered if they were usable at near-VLF frequencies (they’re specified from 100kHz-8Ghz).
They turned out quite acceptable 👍🏼🙂🙂
I don’t need that many, at all 😂, but it was a bargain and I’ll likely sell some of them once I’m done with the tests.
Amazing you can make an almost flat frequency response that wide 😳 They’re NOS from 2013, but they don’t seem to age, shelf life is ‘eternal’ on these devices ☺️
Looking for #recommendations for #usb #wideband #radio #receiver please. Interested in #VLF up to a few #GHz, mostly want to hear #sferics, #hamradio, #shortwave, #solar, #jovian and any curiosities besides.
Would one single #SDR receiver span all that comfortably? Could it be used with some sort of computer visualisation software to watch the passband go by over time?
Got my #RSGB M-class callsign over 20 years ago, now curious about RF again :)
TYVM
Is it possible to make an #antenna for the difficult #VLF frequency band, where the resonant dipole length is usually much longer than the available space for a VLF antenna, in which the absorption of the desired signal is assisted by nuclear magnetic resonance?
That sounds very goofy perhaps, but it occurred to me that this is one of the very few physical processes I can think of whose RF absorption maximum can be tuned down to kHz frequencies by using a sufficiently small external magnetic field and a nucleus with a low magnetogyric ratio.
Due to the initial antenna connection problem, I missed the tuning-up, but most of today's SAQ is here. A strong, ~S7 signal today, with a clear signal from the carrier during key-up times.
Frequency control was excellent today, well within the design +/-10Hz. Given it's an electromechanically-regulated spinning metal disc, this is always pretty amazing!
24 December 2025: The Very Low Frequency (VLF) transmitter from Grimeton (Sweden) with the call sign SAQ goes on air. Is it possible to receive this transmitter with simple means in the city of Bern? Yes, it is possible.
Antenna: (DIY) three ferrite rods wound with HF litz wire.
DIY up-converter.
Degen DE1103 receiver.
The signal was weak, but it was still possible to copy it.
Cold War VLF and a Bob’s Homemade “LWL” QSL Card
https://swling.com/blog/2025/12/cold-war-vlf-and-a-bobs-homemade-lwl-qsl-card/
Tonight I'll play a new work, Radio Strata in Esc Gallery - Graz.
It is a journey in radio recordings I've made, from cosmic sources towards Earth, passing through satellites.
Come for the ending of the "Out of Control" exhibition! More infos here:
https://esc.mur.at/en/projekt/out-control
(Big thx to @reni )
Søren Kjærsgaard
Tilda Moose, citizen
Mx. Chara Aznable (they/them) of Pnictogen
MW1CFN
sperber64
Jeremy
Vilius
SWLing Post
Arnie the DXman
Nicolas Montgermont