Wireless Waffle - A whole spectrum of radio related rubbish
Vodafone rapped over knuckles for roaming scamsignal strength
Saturday 23 December, 2017, 18:01 - Spectrum Management
Posted by Administrator
Back in June of last year, Wireless Waffle discussed the fact that Vodafone had hiked their roaming charges in a number of countries, making even a simple text message cost a fiver or more.

ofcom chastises vodafoneIt seems that we were not the only ones to notice this but that the powers that be took a dim view of it as well. As a result, Vodafone has been forced by the telecoms regulator Ofcom to allow its customers to end their contracts early, if they had been duped into the roaming scam.

On the one hand it's hard to feel sorry for Vodafone for sneaking in these additional roaming charges, when it was faced with a total loss of roaming income from anyone going to Europe as a result of European Commission Decision (EU) 2016/2286 which forces all EU mobile operators to abolish roaming charges between Member states, often dubbed the 'roam like at home' decision. On the other hand, it was a pretty underhand move, especially as the only notice that some Vodafone customers had was a text message - and who bothers to read text messages from their operators?
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Radio Caroline 648 kHzsignal strength
Wednesday 22 November, 2017, 15:31 - Broadcasting, Licensed, Pirate/Clandestine
Posted by Administrator
radio caroline 648 khzWireless Waffle previously sang the praises of the boat trips to visit the Ross Revenge, the home of former radio pirate, Radio Caroline. We also noted that they had been awarded a licence to operate a 1 kiloWatt transmitter on 648 kHz in the Suffolk and north Essex area.

Well, it seems the engineering bods on the east coast have managed to get it together, and recently test transmissions on 648 kHz were spotted by a number of listeners, such as a DXer in Humberside who posted the video below on YouTube.

Though you may not be able to interpret the waterfall display shown on the video, what you see is the Radio Caroline signal in the middle. The two bright lines either side represent radio stations on the adjacent frequencies (639 and 657 kHz respectively). Normally, for AM broadcasting, each station would be allowed to occupy half of the bandwidth between its assigned frequency and the adjacent channels, meaining that it would extend +/- 4.5 kHz either side of its centre frequency. It is this limitation they gives medium and long wave broadcasting their characteristic 'muddy' sound, as the limitation in spectrum also restricts the amount of audio bandwidth that can be transmitted.

It's therefore notable that the Radio Caroline transmission on 648 kHz extends far closer to the adjacent frequencies than 4.5 kHz. It appears closer to +/- 6.5 kHz wide (or maybe even more). This would allow the station to transmit a wider audio bandwidth and thus sound a little 'brighter' on-air. Such derogations from the norm are not unusual as the medium wave band has become emptier, as there is more space for stations to spread out and sound better.

As an example, the three audio clips below have been filtered with different bandwidths. Just click on the relevant button to hear the difference (note that this doesn't work in all browsers.

Audio BandwidthPlay
15 kHz, stereo (FM Stereo)FM Stereo
6.5 kHz, mono (extended bandwidth AM)AM 6.5 kHz
4.5 kHz, mono (standard bandwidth AM)AM 4.5 kHz

trevor radio carolineGiven that of the neighbouring frequencies, the nearest stations on 639 kHz are in the Czech Republic and Spain (previously crowned the queen of medium-wave broadcasting) and on 657 kHz in Spain (again) and North Wales, it seems unlikely that the additional bandwidth being used by Radio Caroline will give any problems and we are sure that listeners will enjoy the cleaner, brighter sound that they will have on-air.
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Digital UK Magic Spectrum from Nowheresignal strength
Tuesday 21 November, 2017, 10:27 - Broadcasting, Licensed, Spectrum Management
Posted by Administrator
digital uk nov 2017Digital UK, the organisation responsible for promoting digital terrestrial television in the UK, has recently published a white paper it commissioned from consultants Aetha and Webb Search entitled 'The defragmentation dividend: A more efficient use of the UHF band'. The paper hypothesises that by re-organising the UHF (e.g. sub 1 GHz) spectrum available to mobile operators, it would be possible to use it more efficiently and deliver more service from the same amount of spectrum.

The paper identifies the fact that, at present, the 'digital dividend' spectrum (e.g. that which has been released from television broadcasting due to the increased efficiency of digital transmission over its old analogue counterpart), is broken up into a number of fragmented pieces whose usage is not optimum. This is certainly true: the figure below shows the current set of allocations within the frequency range 694 - 960 MHz.

694 960 mhz plan

The mobile allocations at present are as follows:

BandUplink (MHz)Downlink (MHz)Amount (MHz)Notes
900 MHz876-915921-96078Including GSM-R
800 MHz832-862791-82160
700 MHz (a)703-733758-78860FDD
700 MHz (b)738-75315TDD or Downlink

In addition there is approximately 29 MHz set-aside for short-range devices. Thus, of the total of 266 MHz of spectrum between 694 and 960 MHz, 213 MHz (80%) is allocated to mobile services, 29 MHz (11%) for short-range devices leaving 24 MHz (9%) 'empty' (mostly for guard-bands to protect services on adjacent frequencies from interfering with each other). The theory is that by re-arranging the band, it is possible to use all of the small gaps that currently exist between the various mobile allocations (e.g. the 9% that is empty) for more mobile services.

One of the problems of the plans proposed in the report is that although they increase the amount of spectrum for mobile services to up to 250 MHz in their most extreme case, they also reduce the amount available for short-range devices from 29 MHz to just 16 MHz. Whilst you may be thinking, "isn't mobile a better use of spectrum than short-range devices", the fact is that an increasingly wide ecosystem of devices is supported in this spectrum. It includes radiomicrophones and wireless headphones but perhaps even more critically, a growing number of Internet of Things (IoT) technologies that are seen by many as being at the centre of the next stages in the development of the Internet. This includes sensors (e.g. thermostats, light sensors), smart meters (electricity, gas and water) and a wide range of smart-city applications such as transport management. Digital UK's proposed plans involve changing the frequencies used by these devices, which is notoriously difficult. How long, for example, do the keyfobs that unlock your car door last - as long as the vehicle itself in most cases. So clearing a short-range device frequency won't be completed until every device in a band has been replaced by a new one.

The report only pays passing comment to the new 600 MHz mobile band that is being implemented in the USA. In fact, the report seems to suggest that even its most conservative re-organisation option would release so much capacity that there would be no need for the 600 MHz band:
...even the more modest increase of 25% in Option 1 would be similar to the capacity that could be provided by repurposing the 600MHz band...

mobile uplink downlinkIt makes this claim as a result of an oddity of current mobile technology, in which the amount of spectrum (and capacity) that is available to a mobile user is roughly equally split in the uplink and downlink directions (e.g. to the network from the user, and from the network to the user respectively). If the band was re-purposed as Time Division Duplex (TDD), the share of uplink and downlink capacity can be changed, and the report assumes that 80% of overall capacity would be made available for downlink and 20% for uplink (this is in fact in line with current estimates of the real split of usage). If this is the crux of the argument, then doing nothing at all to actually change the overall amount of mobile capacity available, but changing all of the existing allocations to TDD would approximately yield a 60% 'improvement' in downlink capacity, but this would be to the loss of uplink capacity which would fall by 250%! There is no gain without pain. In addition, TDD operators in adjacent mobile spectrum need to fully synchronise their networks otherwise there needs to be a guard-band between them, reducing the overall efficiency of use and opening up new gaps.

Whilst the report makes a valid argument about whether the future of mobile should be TDD or FDD, it is perhaps no surprise that it chooses this solution to theorise about an improvement in the efficiency of use of UHF spectrum, over and above the use of the new 600 MHz band, whose use would obviously entail the loss of (yet) more spectrum for digital terrestrial television. Sadly for Digital UK, the required pain, in terms of re-organising existing mobile networks, and replacing all short-range devices is sadly never going to counterbalance the gain of a few extra MHz of UHF spectrum.
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Halloween Hits Remindersignal strength
Sunday 29 October, 2017, 21:19 - Much Ado About Nothing
Posted by Administrator
witchcraftyJust a quick reminder, as Halloween is but 2 dastardly days away, to take a look at our list of One Hundred Halloween Hits.

The list of horrendous hell-bound hits has now easily exceeded a blood-curdling century, but 'one hundred and sixteen and a bit Halloween hits' doesn't have quite the same ghastly ghoulish ring to it, now does it?

If you need a playlist for your All Hallows' Eve party, look no further than this fiendish selection of scary songs. Get ready to be afraider than you've never been before.

And if you don't know your Zombie from your Lil' Devil, or your Highway From Hell from your Road To Hell, this list is for you!

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