The Future of Short Waves

[wireful3]

We live in a compact country. It is possible that in vast countries SW might still be an option for long range coverage, especially where the cost and running of receivers is an issue.

I guess that Australians for instance would not consider London to Glasgow very far. There are cities within Australia and America for instance that are separated by distances that make the Atlantic seem not too big. I have occasionally wondered if that is the reason why so many Russian radios had such good SW coverage, it is also rather big.

There may well be interesting AM broadcasts on SW for some time to come.

[russell_w_b]

Which is why, John, I suspect China is seeing an upsurge of HF broadcasting. Their transmissions boom into the UK clear as a bell, but their own continent can be covered on one or two hops. The BBC relays on Kranji (Singapore) and Nakhon Sawan (Thailand) provide our alternative voice to those parts.

I think there was a discussion once on here about the NVIS possibility of covering our small island, but it wouldn't be anything more than a novelty in a developed country where internet and digital transmissions are the norm, and the only reason I see it being used in a broadcast capacity would be as a 'belt-and-braces' system if everything we enjoy currently went pear-shaped for whatever reason. A couch-potato populace used to zapping 'n' surfing and consistent digital sound quality would not take kindly to retuning their sets as propagation conditions vary and different frequencies are used daily, seasonally, yearly...

Even so, there wouldn't be many HF receivers to pick things up. They would have to be doled out as needed and the current advice about the MF / LF set kept sealed in a biscuit tin would have to be updated.

[Ian - G4JQT]

Originally Posted by russell_w_b

I think there was a discussion once on here about the NVIS possibility of covering our small island, but it wouldn't be anything more than a novelty in a developed country where internet and digital transmissions are the norm [...]

Yes, about 10 kW of NVIS (Near Vertical Incidence Skywave) on about 5 MHz using DRM from Daventry (now closed) or Droitwich was considered adequate to cover the UK.

Unfortunately, the tests done in the mind 1990s (I think) showed that the very unstable propagation conditions for NVIS at dawn and dusk revealed the shortcomings and impracticalities of the idea, even using DRM...

Ian

[Variometer]

Half an hour ago, I got my old Regentone working again and was very pleased to find that the short waves are still very lively between 6 and 18mHz (that is the waveband) of the set. All the morse has gone, of course, but still plenty to pick up.
Can't imagine it will finish all that quickly.
Bob

[russell_w_b]

Originally Posted by Variometer

Can't imagine it will finish all that quickly.

I hope you're right, Bob. But the trend, as inferred here and as far as I can see, is that those developed and now stable nations whose HF service was developed to serve their diverse empires through the last Century will cease HF broadcasting altogether (too expensive; no need for political influence), and that those developing countries who feel the need to broadcast one voice to their people where the infrastructure won't support other means of promulgation will develop HF broadcasting to good effect.

Regrettably, the 'knock-on' effect of the likes of BBC, VoA, Deutsche-Welle, etc... pulling out will seriously curtail what's available to listen to.

You might be interested in what's discussed here. It makes grim reading.

[Variometer]

With me, it isn't that I actually listen (or pay much attention) to much at all when it comes to radio. I am more interested in the fact that I can pick something up to prove that the radio that I have built or repaired works. Doesn't matter to me what language it is in really. But listening in today to the HF bands for the first time in quite a few years, they still seem to be quite well populated and I can't imagine it dying out in the foreseeable future. As others have said, lots of AM stations may well spring up,even if they are pirates. The vast majority of us here are quite capable of building AM transmitters for legitimate experimental purposes and that may well be more interesting than ever. We will have to wait and see though. Thanks for all replies - very interesting and food for thought!
Bob

[HMV 1120]

I was listening to the BBC WS whilst visiting Dubai over the christmas period, with good reception between 6-7 Mhz and 11-12 Mhz (I forget the exact frequencies). The quality of the programing really is excellent in comparison to the local alternatives.

Would these transmissions have been sent from Skelton?

Rob

[russell_w_b]

Originally Posted by HMV 1120

Would these transmissions have been sent from Skelton?

Doubtful... The only BBC programmes in English emanating from Skelton (on the current schedule) are 'English for Europe' on 5.940 MHz between 03:00 and 04:00 UTC aimed 110°, so it might have been that transmission, as it continues beyond Europe down to the E. of Suez.

The other BBC programme in English from Skelton is digital (DRM) from 05:00 - 07:00 UTC on 3.955 MHz.

Most of Skelton BBC transmissions are Arabic.

HTH

[Radio Wrangler]

Certainly, an HF pantry transmitter would not pose any difficulty... a simple packaged crystal oscillator into a modulator and AM is easy. SSB is more fun.

But, it would be your own signal and you'd know what was coming. The whole business of exploration and finding the unknown and unexpected, which has always been the real 'hook' of shortwave will be missing.

A music/speech source for demonstrating the ambience of period radios to visitors, I can understand.

David

[Variometer]

I have been listening in again this morning on my reincarnated Regentone. I find that between 6 and 18 mHz, (the coverage of the set) it is packed with stations, many of them speaking English, although obviously foreign. Didn't hear any morse, but not really bothered about that! I really can't see it all disappearing in the near future. World powers might declare that they wish it to end, but that might well provoke more stations to spring up.Two days ago, I was considering getting rid of all my valves & components in preparation for the decline. But I have now abandoned that idea and will just ignore all the prophecies of doom until such a time as they come about - if they come about!
Bob

[dave walsh]

It's notoriously hard to predict the future isn't it Bob? This may not be an either or situation and there is not enough info to be sure about anything really but then look how quickly mobile ophones took over! I think that [ironically] interest in vintage gear might increase even if say, SW terrestial broadcasting does become a thing of the past. As with modern technology new ways of using it may well emerge-it's private for example. On the internet or a mobile, nothing much is-including your location! Either way, an impulse decision to get rid of everything as a former Forum member did quite recently [to the tip as well] is a dangerous game. I did something similar on a very, very much smaller scale 40 years ago and I still regret it now.
Dave W

[Variometer]

Yes, I did something similar about 35 years ago, but I had the good sense to keep the valves and variable capacitors. It was just a fleeting idea that I had a few days ago, but it has passed now and I will not be getting rid of it all. In any any case, I could never have even contemplated sending it to the tip! When valuable valves come into my possession, I must admit I can't get rid of them fast enough. I really prefer working with more common types such as the little battery Dks, DAFs etc and other common as muck types such as EF91 EF80 EF39 6V6 and similar. Then if I ruin one, it doesn't matter so much.
Radio isn't my main hobby, but I am going through a radio phase at the moment.
Bob

[Hybrid tellies]

At the moment there is still quite a lot to listen to on the shortwaves from stations such as BBC WS, China Radio International. Voice of America. Radio Australia, Radio Romania Int, Spain, Voice of Russia. All these still broadcast in English and some beamed to Europe and can be heard on modest receivers. But the future of short wave broadcasts is uncertain. Every evening the 49m band would be crambed with strong signals but now it's quieter with only a few strong signals but this does allow reception of weaker more distant signals.
For some people the fate of shortwave radio has already been sealed by the dreaded PLT adapters.

I use this http://home.centurytel.net/danielsampson/ to find something understandable for me.

[greenstar]

The thing I can't understand is the apparent absence of any concept in our poliicies of a basic fall-back technology. Digital radio is surely far more complex, localised and vulnerable, mobile networks go down in disasters, and cable/internet are similarly vulnerable. When I am more paranoid I do wonder if the shift to digital is more about political monitoring and control. Given what we are seeing with climate change events and potential terrorist acts the need for something simple, reliable and widely available seems clear enough.

[Radio Wrangler]

In case of national emergency, the government plan used to be for BBC transmitters to run on Diesel generators, and for the population to use trannies to listen for government orders.

Auntie beeb doesn't own her transmitters any longer.

DAB radios eat batteries for breakfast, so the government is going to have to get uncharacteristically decisive and uncharacteristically quick in order to issue its commands before all the DAB receivers are exhausted, even if the free-market transmitters are running.

The cellphone network already collapses in any area with a bit of a disaster. There are plans however to close the networks to all except priority users. Airwave should still be running. Freeview shares all the weaknesses of DAB. So the government people ought to be able to talk amongst themselves, but not talk to the population.

Once the last AM/FM portables go, there is no plan B. Joe public won't have any equipment for any plan B.


Raynet will probably still be functional and connected to county emergency planning officers, but the public end will be down to knocking on doors and word of mouth.

That's the blackest view. On the other hand, I doubt if the Band II spectrum can be flogged off until something is done about the effectiveness of DAB in cars.

Shortwave broadcast is diminishing, but I think it will hang on for a long time. ITU politics mean that small countries shouldn't be trampled.

Who'd have thought we'd miss those tractor production figures? Things are a bit bland, now, and I wonder how long the single-letter beacons will keep going?

David

[emeritus]

A "Wireless World" article of the early 1940's condemned contemporary proposals to replace broadcasting with wired transmissions, as wired transmissions would be subject to governement censorship and remove the possibility of receiving news from other countries. It seems that, with the advent of internet radio, we are now moving towards the situation that was deprecated in the 1940's. I will have to dig out the issue, buried in the back of my loft I think.

When London was the subject of a terrorist bombing attack in the 1990's, not only did the phones stop working in central London where I was working at the time, but we were instructed to remain in our offices, and there was a total news blackout in UK media as to what was going on. As I speak Spanish, I was however able to get up to date information on the situation in London from the Spanish newspaper "El Mundo"s web site, which referred to the fact that a few months earlier the BBC had issued a press release saying that there would be a news blackout if a terrorist attack happened. No mention of this press release was made in the UK media.

[Variometer]

On considering the matter, I feel that the HF bands will last indefinitely. My mind is "unclouded by fact" for the most part, so really, I don't know what I am talking about But it does make for peace of mind
I don't even know what PLT means. Tried to Google it and came up with loads of things, none related to radio - how about "Patent Law Treaty?"

Another thing to remember is that whenever we go on the internet, there is someone, somewhere noting down every site we look on and what we are up to, ready to use it against us should the opportunity arise. Nobody, however, has the slightest idea what I listened to on my SW receiver last night!

Last week, I sold a science magazine on Ebay. Yesterday, we received a letter supposedly from that magazine offering us a £142 discount on a year's subscription! Obviously, someone saw it there and is "trying it on" Maybe genuine, maybe a scam, but it demonstrates lack of privacy online.

Whenever I look for something online, I note that I am bombarded by adverts or e-mails advertising it for some time after. That suggests that I am being watched all the time.

Bob

[russell_w_b]

PLT is 'Power Line Telecommunications'. The injection of interference-causing data (in the HF bands) down power cables, usually overhead, so the overhead rural distribution system, typically, acts like a huge aerial.

Ironically, there is an experimental PLT image / data system on trial on one of Skelton Transmitting Station's 11kV incoming supplies!

[Radio Wrangler]

Power Line Transmission of data, Bob.

If you have ADSL 'Broadband' at home, it's the superimposition of high frequency signals on your twisted-pair phone line. The DC and audio stuff goes to-from your plain old telephone, the HF stuff goes to your ADSL modem (Asymmetric, Digital Subscriber Loop) and thence to your computer. The phone wiring isn't perfect for this. Some signal energy gets radiated, and there is cross-talk between circuits where pairs are combined into larger cables. The radiated signal causes radio interference.

The same game can be worked on your 240V mains supply. Power companies would just love to get in on the revenue stream, and their cables are already there. The problem is that mains wiring is much less balanced than phone wiring and any signals are radiated all over the place. The mains wiring is a more effective antenna than the phone wiring, so the radio interference potential is greater than phone line ADSL.

There's an odd law in communications theory which says that any channel filled with the maximum rate of data it can carry looks like white noise. THese different data passing schemes get close to this. THe effect of leaked data traffic seems more like an elevated background noise level rather than discrete tones that can be pointed at and blamed. Sure, there are discrete components that get spotted, but the insidious rise of mush gets blamed on band conditions.

There IS one hope shining through all this: The insatiable desire for faster and faster connections.

We are currently using the phone lines from homes to exchanges at pretty much the absolute limit of what they can carry. The BT infinity about which we're all being bombarded is sort of half-way fibre. They don't tell you this. Their exchanges connect via new optical fibres to cabinets in streets, and your phone line is looped into the gear in the cabinet. Your internet connection is now only a short distance, and more importantly, isn't so closely bundled with so many other pairs. Your data rate goes up, which they do tell you about. The reduction in crosstalk means they don't need to put up the power of the HF components for the faster rate. It also means that the muck is spread over a wider frequency range, and it also means that the total length of RF hot wire is less. This is generally better for people who want to use RF frequencies for radio. FTTC Fibre To The Cabinet is only a stop-gap until domestic demands force FTTP Fibre To The Premises. "I want that blockbuster movie in beyond HD, and I want it NOW!" along with total immersion gaming as more people try to escape reality and shoot people/things will demand it.

The power company's PLT version has a big speed disadvantage in that their network reaches groups of consumers in parallel, so frequency ranges have to be split amongst users. They already have to put equipment out in substations to try to divide the newtwork up as much as they can.

PLT is very dirty, very nasty and looks like the end of the world for LF/MF/HF radio but its days are numbered. Joe Public's appetite for data will kill it.

Phone line ADSL is dirty too, not so dirty per circuit, but there are so many more circuits. But it too is now on borrowed time. The last few hundred metres to each home, times the number of homes represents a hell of a lot of digging, but I think it's going to be done eventually. FTTC jokingly called 'infinity' (Well they were either joking, cynical or stupid) is a stop-gap.

Once all the muck stops being radiated, the HF bands won't come up as clean as new. There's the other problems...

Some folk have bought 'smart plugs' which shove data around their house wiring. These are spectacularly filthy. but maybe their data rate will begin to disappoint?

Longer term, the general profusion of electronic doodads is raising noise floors. Allowed levels of RF radiation, per item, were set long ago when it was not anticipated just how many electronic doodads the average home has running at once.

The only hope in this area comes down to energy pricing and saving. People are starting to be aware that they are paying for all those clock displays and things running on stand-by.

I think that for a power company, PLT is a dodgy investment, because its best before date may have already passed.

When I come across in-house digital plug PLT, I just make a comment about 'Do you know how far away someone can eavesdrop on all your data?' just to discourage the things Sometimes a little paranoia can be a good thing.



David