News
Raspberry Pi
Written by Bryce Ringwood   

The Raspberry Pi is now available without a long wait. It is a small computer intended to assist students with understanding computers and programming. About the size of a pack of cards, it has 256Mb of RAM and uses an ARM processor, I imagine similar to that used in many mobile phones. The standard operating system for it, is LINUX, and it uses a TV set as the monitor. The cost is under R300, excluding keyboard and mouse.

I placed a small article on geting started with the Rasberry Pi in "Experimenters Corner", although there are may other good articles on the internet to get you going if you haven't summoned up the courage to switch it on.

I know - its not an "oldradio" topic, but the same type of people who fix oldradios are often interested in this type of thing as well. Funnily enough, you also get people who are happy fixing radio sets, but wouldn't go near a computer at all.  Therein lies one of my dilemmas.

Most old/antique restoration web-sites cater purely for the radio serviceman, shall we say, "of a certain age". Well, I'm as old as that too - but it seems to me that we need technical ability and interest to be generated in the youth of today. For that reason, I hope to include a certain amount of educational material here. You will probably have noticed in the Javascript programs that they are slanted more to an educational approach than to a practical "what resistor do I need here" type of story. I started doing programs for another web-site which were geared to "solving serviceman's problems" - but lost interest.

Maybe I'll get back to them. I don't know.

In the meantimme, the Raspberry Pi beats the pants of a Pl*yst*tion.

 

 
The Monopolisation of Software
Written by Bryce Ringwood   

I notice a disturbing trend towards concentrating the availability of software into a small number of suppliers. This is regardless of who wrote the software in the first place. The idea is that all software for a particular device shall only be available through an "app store". The rationale being that the device is then made secure from malware, because the software has been tested.

Naturally, the software author has to pay a fee to the "app store" provider for the pleasure of having his software on the shelves, and the "app store' itself makes a percentage on each item sold.

It seems to me that this does not assist the "open source movement". It also means that downloading from a site like this one won't work in time to come. (Except, of course, those old DOS programs).

We'll have to see how all this plays out, but it is begining to look as if the web will be the last remaining area of free creativity. This web-site, for example, is written using a content management system called Joomla! - which is free to use under the terms of the GPL.

Please support the open source movement, without which, there would be far fewer web-sites and less opportunities for people to learn. Open source matters particularly to people on our continent where costly software is another stumbling block to education and progress.

(By the way, you may use the programs on this site at your own risk. They are there simply as illustrations of how to solve programming problems. You can have the code for the programs on request by emailing me.) 

 

 

 
The (Further) Decline of Short-Wave
Written by Bryce Ringwood   

On Sunday, 24th June, 2012 Radio Canada International closed down its shortwave radio transmissions. This is just another station in a long list of others that have closed down their transmitters. Radio Netherlands (RNW) followed suit shortly thereafter. As of April 2013 those two stalwarts of shortwave, the BBC and Voice of America have introduced cutbacks in their shortwave broadcasting service. Indeed, shortwave is now becoming eerily silent. At  least there is some ham radio CW activity on the 15 metre band to convince me my set actually works.

In the UK, there is a plan afoot to remove all analogue broadcasting ("analogue switchoff"). Manufacturers seem to be preparing for this, with the introduction of DAB only (Digital Audio Broadcasting) in new car audio systems. There seem to have been some trials of DRM (Digital Radio Mondiale) on the medium-wave bands.

According to worlddmb.org, some trial DAB+ transmissions are taking place in South Africa. I wouldn't go buyiing a DAB set in the UK and trying it here, because there may be significant differenes in the ultimate broadcasing standards. In other words - the set might not work here!

There are other problems. I tried to explain to an elderly relative how to use her DAB radio to receive "Classic FM" on her DAB radio. She believes (possibly quite rightly) that radios should always be left unplugged when not in use. This particular radio would take some considerable time to "reboot" every time it was plugged in - and then a further "standby" switch had to be pressed to make it operate. There was a tuning knob, but this operated more like a scanner's tuning control. The set remains gathering dust and unused in a corner.

The 1950s were probably the hey-day of shortwave broadcasting. This was the cold war era when Radio Moscow and Voice of America would fling accusations and counter-accusations at each other. They would try to jam each others signals and times were quite interesting. At the same time there was lots of Ham Radio activity, with people changing from AM to SSB transmissions and you could hear stations across the world on a decent radio with a piece of wet string for an aerial.

All we have now are a few comparatively parochial conflicts with most news reports coming out of the affected countries via smart phone - until the authorites block the signals.

Admittedly, on the technical front shortwave has been superseded, not only by Internet radio, but also satellite radio on digital TV channels. (Satellite radio itself was not successful in Southern Africa, and is all but defunct with less than a handful of broadcasters.) I wonder just how many listeners use Internet radio - I imagine very few, with most of those being people who listen to the regular FM stations via Internet on their work computer.

The other thing that is causing a decline, I believe, is the lack of sunspot activity - which seems to have neatly coincided with mankind's increased reliance on satellite and digital terrestrial transmissions. The way things are going, it looks like sunspots will disappear some time in 2015. This would not be the first time the sun has stopped providing sunspots. The Maunder Minimum of the period 1645 to 1715 was a period when almost no sunspots were recorded.

Further, arguably, the people of today have a different mind-set than people of the '50s. They are more likely to spend time constructing "virtual things" on computers than "real life" things on a workbench. This is fair enough - change is inevitable.

And what of "Digital Radio Mondiale" ? - It is beginning to look as if it will never happen. I have not yet seen a DRM receiver "in the flesh" - maybe like Worldspace it will never come to full fruition. This was once promised to be the saviour of shortwave, as it would allow high quality transmissions, free from interference. As far as I know, there are no transmissions receivable here in Johannesburg.

Be that as it may, many parts of the world don't have internet and mobile phone coverage to the extent that we enjoy it here in South Africa and they still rely on shortwave for their news. The reason that shortwave is closing down does not seem to be technical or to do with the solar climate, but rather to do with accountancy and politics.  Let's hope the men in grey suits that look at the numbers spare a thought for the less fortunate population and reconsider their verdicts.

PS SABC is on shortwave as Channel Africa - Use it or lose it. 9625 kHz on the dial.

 


Joomla template by a4joomla