[digitalsankhara]

You covered all the points I was going to make. As part of the pre-internet generation that grew up with radio and a ham radio operator since my school years this is second nature and common sense to me.

It is interesting that governments have long recognised the power of shortwave such that they have restricted what a citizen can do with it. In wartime, ham radio is usually made illegal. The recipient of a broadcast cannot be detected (save some very local factors - meters range) which is why governments around the world still use shortwave number stations to transmit coded instructions to spies.

I suspect the removal of AM radio in EVs is also because the cost to RF shield the car against EM emissions in that frequency range was deemed too high for the audience it would address, and maybe just lazy or engineering too. Agree, very short sighted.

Hell, even the BBC in the UK is closing down local AM transmitters on cost grounds (but I suspect there is political pressure to move the masses to digital UHF infrastructure).

A medium wave/shortwave transmitter is the ultimate in post apocalyptic film memes!

[BoxOfRain]

> Hell, even the BBC in the UK is closing down local AM transmitters on cost grounds (but I suspect there is political pressure to move the masses to digital UHF infrastructure).

Yeah in a couple of years it'll just be Radio Caroline and various small-time pirates on AM. Even the venerable longwave transmitter for Radio 4 is getting shut down in a couple of months sadly.

Can't help feeling this is all a bit short-sighted, it's not like you can do anything else with those bands and if things go sideways it's a reliable way to reach a lot of people without power. Personally if we can't keep our medium and long wave transmitters on economic grounds I think those bands should be opened to unlicensed hobbyists, it'd be an excellent technical and artistic opportunity that would allow for actual broadcasting rather than just two-way communication. I doubt there'd be a huge issue with interference as few people have the room to put up a 150' quarter wave, and if copyrights were a material issue rights holders would have gone after public SDRs capturing the broadcast bands years ago.

[digitalsankhara]

Totally agree. Thought about this myself, as a way of having true community radio. A simple hobby broadcast license of low cost might be pooled to cover copyright music only to prevent the types raids of seen on pirate stations (leaving aside what politics can be read into that enforcement). Maybe that would not be such an issue these days, but anyway, there is a lot of Creative Commons content out there.

I love listening to the North Sea pirates on medium wave. So diverse and ecletic!

[hilbert42]

"I love listening to the North Sea pirates on medium wave. So diverse and ecletic!"

I lived on the other side of the planet the 1960s when Radio Caroline began transmission so I was deprived of the somewhat 'illicit' fun of listening to it.

Instead I'd come home from school turn on my shortwave radio and witness Radio Moscow and Radio Peking battling it out for the position of which could produce the most outrageous and over-the-top propaganda. It was hilarious, even this naïve school kid wasn't taken in by any of it.

That was at the height of the Cold War (Cuban Missile Crisis, etc.) and especially Radio Moscow could be heard splattered all over the dial—it seemed that no matter where one tuned, it came in at strength 5/9+, its signal was enormous.

I'd love to hear some recording of those broadcasts again and I reckon I'd still be amused (I've not searched but I'd bet there are recording of them in archives somewhere).

[digitalsankhara]

It's interesting that today Radio China International is everywhere on shortwave.

[hilbert42]

"…it'll just be Radio Caroline and various small-time pirates on AM. Even the venerable longwave transmitter for Radio 4 is getting shut down in a couple of months sadly."

Even with this shortsighted decision, the size of the UK is such that FM and digital services can provide adequate coverage. But that's not the case for large countries like the US, Canada, Australia, etc. VHF services major population centres with comparative ease but it's essentially impossible for it to do so for vast sparsely-populated areas. This is where LF, MF and HF are effective.

Years ago I recall traveling by car from Sydney to Adelaide (Australia) which is about 1000 miles and the shortest route is to travel diagonally across the country (the longer way would be to travel the coastline where the population is larger and take in cities such as Melbourne).

Traveling cross-country meant going across sparsely-populated areas where local broadcast services were either nonexistent or very patchy (low power—just enough to service a small community). Nevertheless, that proved no problem as the ABC's (the Oz version of the BBC) capital city AM transmitters located in Sydney, Melbourne and Adelaide provided coverage all the way. Even though Melbourne wasn't on route at points along the way its transmitter was stronger than the other two. (I'd note that was the daytime coverage from all three transmitters sans skip.)

It would be impossible to provide that coverage with only three VHF transmittes no matter their power. Frankly, it'd be crazy to switch off AM transmissions in a country like Australia even if one discounted their strategic advantage.

[dalke]

> such that they have restricted what a citizen can do with it

My grandfather, born in Canada and later naturalized as a US citizen, got his ham ticket back in the 1960s, but, as he wrote: "This was O.K. for one year but to renew & become general I would have to obtain more than just a US passport; It would be necessary to get a certificate of citizenship. This took years and during those years I landed up in the Dom. Republic & got my Ham ticket there without it, HI3XRD."

He later moved to Miami. When Hurricane David came through the D.R. in 1979, he was one of the ham volunteers who helped handle communications from the island.

Oh, and he never got Extra because while he could manage 13 wpm for General or Advanced, he couldn't manage the 20 wpm for Extra.

[hilbert42]

"It would be necessary to get a certificate of citizenship. This took years and during those years I landed up in the Dom. Republic & got my Ham ticket there without it, HI3XRD.""

Thank you very much for pointing that out. I'm in Australia and I've often pointed to the fact that many countries restricted access to the radio spectrum for many reasons—to limit EMI, for state security and strategic reasons, ensure secrecy of communications, etc.

For example, when I got my amateur ticket whilst still at school in the 1960s I had to sign a Declaration of Secrecy and have it witnessed by a registered JP. The reason was that people such as us could come across important transmissions (messages) of a strategic nature that should not be allowed to fall into the wrong hands.

Come mobile phones, WiFi etc. that changed without any real public discussion whatsoever.

What I find absolutely amazing is how—by sleight-of-hand—Big Tech sideslipped both very tight telephony and radiocommunications laws to violate say privacy on smartphones, and the fact that they've gotten away with it. The smartphone generation hasn't a clue about any of this stuff. Right, once the privacy of telephonic communications was inviolable, now it's a fucking joke.

On the matter of the declaration of secrecy, amateurs could possibly come across unencrypted telephonic communications, ship-to-shore etc., and as deemed secret, they (rightly) were not allowed to act on that information in any way, in fact jail-time penalties applied if laws were violated.

Incidentally, as my Declaration of Secrecy has never been rescinded I'm still bound by its conditions.

[hilbert42]

"I suspect the removal of AM radio in EVs is also because the cost to RF shield the car against EM emissions in that frequency range was deemed too high for the audience it would address,.…"

The difficulty in suppressing switching noise/RFI is one of the stated reasons EV manufacturers give for removing AM reception. They say that keeping AM will increase EV costs.

If regulators/spectrum management were to agree to their request then that would imply a relaxation of existing EMI emission standards. With thousands of EVs on the roads the noise floor on the HF band and lower frequencies would become intolerable, the band would become unusable.

A while ago on HN I referred to a now-dated NATO communications tech note on interference that said the noise floor on the HF band had increased about 6dB. I went on to mention that about a decade ago I'd mentioned the NATO stats to an engineer from a HF transmitter manufacturing company at a trade show. He responded by asking me where I'd been in recent years and went on to state the noise floor on HF had since increased to about 17dB above the pre-digital switching era.

As I said that was about a decade ago when EVs were still only lab prototypes. If EV manufacturers are allowed to get away with emitting more EMI then the HF bands will become altogether unusable. And no doubt this is a serious problem.

EV manufacturers like Musk have enormous power and what worries me is that spectrum management authorities around the world will cave in further to pressure and relax EMI standards even more.

That increase in the noise floor from 6dB to 17dB was the result of spectrum management caving in to commercial pressure from the 1980s onwards. This was the era of deregulation and EMI regulations were loosened—EMR/noise testing etc. was not only relaxed but further outsourced.

It seems to me those who've a vested interest in the LF/MF/HF bands and want them preserved/saved from interference need to join forces and make concerted efforts to save them. An unlikely alliance of say the military, amateur radio (IARU), broadcasters and others speaking in unison to governments/ITU is what's needed to save these bands.

BTW, I once held an AR license which I got whilst I was still at school.