The Future of Short Waves

[Variometer]

Thanks,
I have found it now. I have heard of such things, but didn't know what PLT meant. In fact I rarely know what abbreviations mean unless they are obvious
Bob

[Variometer]

David,
Thanks for all the extra info. I was aware of all these things in a vague sort of way, but don't have any and don't intend to get any! Don't really trust radio links such as WIFI either.
When I took voluntary redundancy from electronics, I never made the slightest effort to keep up with modern developments, but regressed to the more pleasurable subject of radio valves and circuits that I generally understand quite well!
When I did my radar certificate, I fortunately got in on the very last exams on valve equipment in 1968!
Bob

[Ian - G4JQT]

Thanks Radio Wrangler for an excellent description of the shortcomings of PLT. I hope you are right in its demise!

I was at a DRM (Digital Tadio Mondial) conference where broadcast engineers were almost tearing their hair out once their tests confirmed that "NO" level of PLT interference was compatible with the reception of DRM. This must have been around 2002/3.

If DRM had been perused for domestic broadcasting, there would have been one hell of a battle between the BBC and the PLT providers. At one meeting a senior engineer was despairing when he said: "They are now planning to use this damn technology just to get data from one side of the room to another and in the process wipe out frequencies used for international communications!"

As has already been discussed here, it looks like DRM's time will never come - at least in the developed world. Let's hope PLT and all its offspring will die off too...

Ian

[Nymrod121]

Originally Posted by Variometer

Thanks,
I have found it now. I have heard of such things, but didn't know what PLT meant. In fact I rarely know what abbreviations mean unless they are obvious
Bob

One of my pet hates! - in my personal opinion, unexplained Multiple-Letter Acronyms (MLAs) are a PITA

[Radio Wrangler]

Pita? that's a sort of bread, isn't it?

If you think PLT is nasty, there's Ultra Wide Band, UWB. the plan is to do short range stuff with spread spectrum, with EACH signal spread across the whole of VHF right up to 10GHz or beyond. The excuse is that the level produced by one signal within the bandwidth of any normal spectrum user is trivial, and different UWB signals can be segregated by their different spreading codes. They don't say what it would be like with millions of the damned things spread around.

Fortunately, the military really, really don't like this one, and it's got attributes which should scare the spooks.

David

[emeritus]

I managed to unearth the WW article I mentioned, which was the September 1943 issue. PDF attached. Unfortnately I do not have a copy of the August 1943 issue which seems to have addressed the "broadcast by wire" proposals about which the WW's editor was so concerned.

With so many people accessing their news via the internet, we seem to be heading towards the situation about which the WW editor had misgivings in 1943, but which at least some of his readers had no problems with.

[trh01uk]

Originally Posted by merlinmaxwell

A shortwave pantry 'modulator', never thought of that. Soldering iron time I think.

Why bother? There are oodles of old AM signal generators out there. You can generally pick up one for £10 at any rally. They have the RF generation and modulator built in. All you have to do is to feed in your audio at a suitable level, and attach your antenna. Job done.

Richard

[dave walsh]

Thank's for posting that fascinating WW article Emeritus. I'm not sure that todays Internet situation quite parallels the feared "monopoly" they are talking about then, except maybe in the case of web reception via a telephone line. As I suggested [p20] it might be different in more rural, satellite based, parts of the world but we don't know yet! There were the same issues when they stared slinging wires between posts for the the early Telegraph.
Dave W

Why bother?

Because I can and it's fun. Why bother with old radios I can get a half decent transistor (IC) set for a tenner.

[x72]

Originally Posted by emeritus

I do not have a copy of the August 1943 issue

Here is a scan. Sorry about the edges.

Re: DRM - I played with it in 1993 and notice that there are no more stations now than there were then.

For listening to BBC WS etc, away from "civilisation", it is difficult to beat a satellite bearer but that cuts off $5 trannies.

[Anthony Thomas]

Switchmode power supplies tend to interfere with AM broadcasts quite readily.

[Hybrid tellies]

Originally Posted by 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.

Oh dear the decline in short wave broadcasts continues. From January 1st 2013 Voice of Russia has switched off their English broadcasts to Europe and North America. They will still be audible but much weaker via their African broadcasts.

[G6Tanuki]

Broadcast-band use of shortwave declines, yes - but there's still signals there if you listen for them!

Earlier today I went to watch a friend playing in my local Rugby-team, and decided to take my PRC320 along in its little backpack. At half-time I fired it up and had a good ten minute chat on 28MHz with a guy in Toronto. This is just using the PRC320's 2.4-metre whip antenna.

G6Tanuki

[John_BS]

I played with it in 1993

I don't think so because the system hadn't been developed then! 2003?

John

[x72]

Originally Posted by John_BS

I don't think so because the system hadn't been developed then! 2003?

John

You're right. The earliest date on the software I have is Dec 2003.

[Ian - G4JQT]

The DRM consortium was formed in 1998. I can't pin down/remember when the first transmissions were made; I thought it was the late 1990s, but it could have been the early 2000s.

Regards,

Ian

[Jonster]

I remember seeing a demonstration of DRM at the Las Vegas NAB show in 2000 so it must have been before then.

[John_BS]

DRM at the Las Vegas NAB show in 2000

here you go!

[ITAM805]

I was listening to Radio Romania, as you do, and on closedown the announcer was reeling off the reception frequencies and mentioned that some of them are in DRM And so they are!

[x72]

I looked back at the DRM schedules from 2003-5 e.g.
http://web.archive.org/web/200404111..._schedule.html
and compared it to today's here:
http://www.drm.org/?page_id=151 (the .pdf is more useful)

It seems that most of the things that I heard in 2003 and 2005 have gone. I found a few logs from the software which showed that DW (3995kHz, 9655kHz) and RTL (6095kHz) for Europe were ok for a couple of hours at a time. Other stations on 1296kHz took out BBCWS at night. BBCWS on 1296kHz finished when Orfordness closed in 2012, I think. I could only see modes A and B in the logs. It looks like DW has teamed up with BBCWS and cut back significantly and I can not find any RTL listings now. I was using an indoor tuned loop and a cobbled together converter to a sound card IF.

The general trend appears to be a move away from N. America and Europe to the east, as others have noted. I was not that impressed with DRM compared to AM, especially its inability to get a message across under adverse conditions. Audio quality is not bad, though.

I've stopped taking the old ICF-7600 overseas. That used to be my link to home. Now it's satellite TV, the 'net or Sirius XM (in N. America).