Long Wave radio era set to end with switch-off

Bit of hindsight bias there, DAB was first developed in the mid 1990s, ubiquitous fast wireless IP in everyone’s pockets is at least a decade, perhaps nearer to 20 years in the future. There are quite a few transitionary technologies that we needn’t have developed had we just waited for something better to come along (but without the R&D into some of them…).

(Also doesn’t analogue FM also kinda cut off fairly abruptly?)

> There’s still a lot of utility stations in the LF/longwave band. Particularly time signals (WWVB in the US, ALS162 in France, DCF77 in Germany, JJY in Japan, etc.)

I meant just the broadcast band 148.5-283.5 kHz. (Though I'd love if 2200m and 630m were just a bit wider.)

> and NDB beacons.

Good point[1]. So 148.5-200 kHz in ITU Region 2 (and keep LowFER allowances on 160-190kHz as a consolation prize.)

[1]https://www.dxinfocentre.com/ndb.htm

In the UK we have 2200m but it's 1W *ERP*, so you're probably running a good couple of kW to get there with any practicable aerial.

We've also got a chunk just off the bottom of MW around 475kHz, which ought to be good for long-range night-time communications. It's licenced for CW, QRSS, and narrow-band digital modes.

Doesn't excuse CHU: two 3kW, one 5kW ERP.

And by the virtue of shortwave propagation, it could be heard across the world. For the past month and a half (from when the news of its impending shutdown was revealed) I was regularly picking it up in Australia right up until the bitter end.

Is that emitted power, consumed power, or effective radiated power? Without knowing that, your power calculations have no meaning.

Radio stations are usually measured by the last of those: Effective radiated power.

You can have a radio station with a 50,000 watt ERP, but running only a 2,500 watt transmitter.

For FM radio stations, it's all about the height of the transmitter above average terrain. For AM, it's about the ground conductivity and frequency.

I once worked at a 1,000-watt AM station that had a signal much larger and clearer signal than the 5,000-watt AM station a few miles away.

I'm not a radio engineer, but I'm sure there are plenty on HN who can correct and clarify what I've written.

"Longwave", usually written without a space, is an informal and not well-defined term for radio frequencies lower than the AM broadcast band, which in Europe is known as "medium wave".

In the USA there have never been commercial longwave stations, though various WWV time signals are broadcast in that band.

Despite the name I would not have guessed you could pick up Atlantic 252 in the US. The quality of it wasn't great for listening to music.

https://en.wikipedia.org/wiki/Atlantic_252

"Although the transmitter was in Ireland, the signal's reach meant that it was often looked upon as a "UK national station". Reception reports were received from such locations as Berlin, Finland, Ibiza and Moscow."

In some way it is short-sited, as radio is a good backup medium for global communications in case the entire Internet ever goes down.

Vacuum tubes also aren't vulnerable to nuclear weapon electro-magnetic pulses.

However, other than ham radio enthusiasts I guess no one listens to analogue radio anymore.

We do spend out quite a lot here in the UK for the BBC. They could easily dump a couple of expensive presenters and use the savings for vacuum tubes, if that is what is needed.

No idea where vacuum tubes were invented but I'm sure the BBC could find someone to make them.

It's hard to believe that civilisation has lost the ability to build longwave radio transmitters.