Wireless Waffle - A whole spectrum of radio related rubbish
World Service English (Take II)signal strength
Saturday 27 December, 2008, 08:29 - Licensed
Posted by Administrator
bbcworldserviceFurther to last month's comments on receiving BBC World Service English in Europe, we've been testing out some of the frequencies that were suggested from the Wireless Waffle HQ in southern Great Britain. At all times checked, at least one BBC English frequency was available and at some times, several were audible. The list below gives the times checked and the frequencies that were audible. A simple rating system has been employed with one * representing poor reception, ** representing reasonable reception and *** representing a nice strong signal.

Reception will change from day-to-day and month-to-month so this list may not remain accurate indefinitely but it shows what can be achieved with a little effort. This list will be updated from time-to-time so check back occasionally if you're missing your Lily Bolero!

07:00 - 08:00 GMT
7255kHz***
9650kHz**
11760kHz**
08:00 - 09:00 GMT
11760kHz**
15400kHz**
09:00 - 10:00 GMT
11760kHz**
15400kHz**
17640kHz**
10:00 - 11:00 GMT
11760kHz** (though annoying co-channel China CNR-1)
11:00 - 12:00 GMT
11760kHz**
15310kHz**
17830kHz*
12:00 - 13:00 GMT
11760kHz**
15310kHz**
17830kHz*
13:00 - 14:00 GMT
11760kHz**
15310kHz**
17640kHz*
14:00 - 15:00 GMT
11760kHz**
17830kHz*
15:00 - 16:00 GMT
12095kHz**
15105kHz**
15400kHz**
17830kHz**
16:00 - 17:00 GMT
12095kHz**
15400kHz**
18:00 - 19:00 GMT
5875kHz**
19:00 - 20:00 GMT
5875kHz**

This information was last updated on 7 January 2009.
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World Service English in Europesignal strength
Saturday 22 November, 2008, 19:39 - Licensed
Posted by Administrator
bbcworldserviceThe end of an era is afoot (or at hand, whichever you prefer). Earlier this year the BBC World Service announced that it has stopped transmission of its English service to Western Europe. No longer will the strains of 'Lili Bolero' or 'Big Ben' be heard on the hour in France, Germany or anywhere east of Moscow. Or will it?

The BBC claim that certain frequencies destined for other parts of the world, notably Western Russia, may still be audible in some parts of Europe for those who absolutely insist on listening to the news from London with loads of hiss, crackle, distortion and fading. But to what extent is this possible? Is World Service short wave reception in Western Europe gone forever or is there still the possibility to listen in?

A scan of the material published by the BBC shows that there are still plenty of transmitters on-air carrying BBC World Service English (albeit different regional variants), pretty much around the clock. The question therefore is whether any of them are audible in Europe.

Whether or not a short wave transmission is audible in any given place depends on a number of factors including the transmission frequency, the time of day (in particular whether the path between transmitter and receiver is in daylight or darkness), the distance between transmitter and receiver and the intended target for the transmission. Take for example the World Service English transmission to Africa from its transmitter site on Ascension Island in the South Atlantic. At various times during the (European) day, this is on a frequency of 17830 kHz. This high frequency propagates well through areas in daylight and the direction of the transmission is roughly the same as the direction from Ascension to most of Europe. The distance between Ascension and Europe requires the transmission to hop into and out of the ionosphere a couple of times but on a normal day, if both ends of the path are in daylight, this should work. Barring any co-channel or strong adjacent channel interference, therefore, the BBC transmission from Ascension should be (and indeed is) audible in Europe.

During the hours of darkness, low frequencies (the 48, 41 and 31 metre band for example) tend to propagate well, whereas during the day, higher frequencies (the 25, 19 and 16 metre bands) will fare better. Taking all this into account, it should be possible to construct a schedule of which BBC World Service English programmes are most likely to be heard in Europe. Of course this will change twice a year as the winter and summer schedules take effect, but the principles should hold true.

With that in mind, here is the Wireless Waffle guide to receiving BBC World Service English in Europe on short wave. The frequencies shown are those that have the best chance of being received in Europe but which are directed to other regions (thus the programming material may not necessarily be appropriate). No account of possible interference has been made (for example it is known that the BBC frequency of 17640 kHz suffers strong adjacent channel interference in Europe from Africa No. 1 on 17630 kHz and China Radio International on 17650 kHz). Other frequencies have strong co-channel and adjacent channel interference too so it's definitely a case of 'if at first you don't succeed, try, try, try again'.

Midnight (GMT) to Dawn

Try:

5970 kHz (from Oman)
6005 kHz (from South Africa/Ascension)
6145 kHz (from Ascension)
6190 kHz (from South Africa)
6195 kHz (from Cyprus)
7105 kHz (from Oman)
7255 kHz (from Ascension)
7320 kHz (from Cyprus)
9410 kHz (from various sites)
9650 kHz (from South Africa)
11760 kHz (from Oman/Cyprus)
11765 kHz (from Oman/Portugal)
12035 kHz (from Cyprus)
12095 kHz (from Cyprus)

Daytime

Try:

11760 kHz (from Oman)
15105 kHz (from South Africa)
15310 kHz (from Thailand)
15400 kHz (from Ascension)
15420 kHz (from Cyprus/South Africa)
17640 kHz (from the Seychelles)
17830 kHz (from Ascension)
21470 kHz (from Ascension)

Dusk to Midnight

Try:

3915 kHz (from Singapore)
5875 kHz (from UK/Cyprus)
5955 kHz (from Oman/Singapore)
6155 kHz (from South Africa)
6190 kHz (from South Africa)
7445 kHz (from South Africa)
12095 kHz (from Cyprus)

Note that these frequencies were taken from the Winter 2008/9 broadcast schedule and may be very out of date if you are reading this in 2013! Also, not all frequencies are on for the whole period (some are not daily either), so you will have to tune around between the ones listed to find the best possible reception for the time you are listening.
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Noisy Neighbourssignal strength
Thursday 30 October, 2008, 22:23 - Amateur Radio
Posted by Administrator
It may appear to have been quiet here at Wireless Waffle over the past couple of months, but that's because a number of things have piqued the interest and we've been doing a bit of experimentation and investigation. The first of them is the issue of Power Line Telecommunications (PLT) also known as Broadband over Power Line (BPL) and in particular the problems being experienced by many UK short-wave radio listeners with it. One of these devices could recently be heard, albeit quietly, across the HF spectrum (oddly it has since disappeared) at Waffle HQ but it raised the question as to how many more there were in the area. To find out, I fitted and HF antenna to my car and connected it to an HF receiver and then drove around a nearby housing estate to see what could be heard.

The antenna used resonated in the 18 MHz (17 metre) amateur band but received perfectly well in the 17 MHz (16 metre) broadcast band. Tuned to a clear channel around 17460 kHz, the car was driven around the area under test. Over the area covered by a small local estate, three devices were detected. Two were almost certainly the 'Comtrend' device, sounding just as the ones that UKQRM has demonstrated on YouTube. The third (shown in red on the map) emitted a more continuous tone, interrupted by occasional blips; the range of this device was somewhat less than the other two. Their range at other frequencies was not tested but anecdotal evidence driving round the area using other antennas and the same receiver suggests that the coverage on frequencies around 27 MHz is similar.

plt bpl interference rangeI've plotted the approximate location of the three devices identified together with the area over which they were clearly receiveable on the map on the right (the map covers approximately a 500 metre by 500 metre area). The blue device had the largest interference range and within the areas marked it is unlikely that any short-wave reception would be possible.

The density of these devices means that over the whole estate, short-wave reception would be virtually impossible. A cursory glance around the area indicated no amateur radio antennas so it is likely the devices are going undetected (or just unreported!) Not a positive result and unless the powers that be do something to halt the spread of these devices, it would be easy to foresee a situation where HF reception could be pretty much impossible over whole towns and cities, in residential areas for certain.

One piece of positive news is that Ofcom have set up a special team to deal with PLT interference and appear to have begun taking the problem seriously. Let's hope that this is more than just paying lip service to the problem before the whole HF spectrum is lost to the laziness of those who can't be bothered to use WiFi or put a piece of wire between various bits of equipment in their home. These devices are a disgrace and a menace and before they wipe out all short-wave reception and neighbour-on-neighbour war breaks out, serious action by the authorities is absolutely necessary.
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Wire-More LAN (Part VI) - Maximise WiFi coverage and reliabilitysignal strength
Thursday 28 August, 2008, 17:12 - Radio Randomness
Posted by Administrator
Like all radio systems, wireless LANs can never be 100% reliable. Many factors affect radio transmission and even in situations where something might be expected to work well, problems can often occur. Wireless LANs suffer from a number of particular problems, not least the frequencies they use (around 2.4 GHz) are easily absorbed and reflected and can suffer from high levels of interference. But with a little care, their coverage and the reliability of the connection can be improved quite easily. Here are the Wireless Waffle top 5 tips for improving WiFi signals.

1. Choose the right channel

Interference from other wireless LANS is the most common cause of network quality degradation. The various surveys that Wireless Waffle has conducted have generally shown that channels 1 and 13 are the least likely to suffer from interference from other wireless LANs. Further, channels 10 upwards are the least likely to suffer interference from other users of the 2.4 GHz band. So generally speaking, in an area with a low likelihood of finding other WiFi users, channels 11, 12 or 13 are likely to be best. In congested areas (i.e. where interference from other WiFi systems is likely to be worse than from other users in the band), channel 1 is the best choice.

2. Position your WiFi hub centrally

Radio coverage from most transmitters radiates in all directions from the point of the transmitter, and this is certainly the case for wireless LAN equipment. It therefore makes total sense to position your central WiFi hub as close as possible to the middle of the area you wish to cover. Further, radio signals travel best if there is a clear path between both ends of the link. If you put the central unit in a cupboard or behind a bookshelf, where the path is already obstructed, coverage will reduce. Place the unit in an place with a clear view of the area you wish to cover, the higher the better (look at hubs installed in public places such as coffee shops and hotels - they are almost always mounted on the roof!)

bluetooth side effects3. Keep your wireless equipment away from other wireless equipment

There are many other sources of radio signals in the typical home or office environment and many of these are on frequencies similar to (or even the same as) WiFi. Placing these other radio sources near to wireless LAN equipment can result in reduced performance from the LAN as it struggles to cope with the interference caused by the other equipment. It's especially important to make sure that equipment such as digital cordless phones, satellite TV downleads, bluetooth and zigbee devices, mobile phones and digital baby alarms are not used in close proximity to a wireless LAN if service quality is not to suffer.

http   www mf2fm com blog  7dBi4. Use equipment with proper aerials

Devices such as USB WiFi adapters are generally quite small and this means that the aerial inside them is also small. Smaller antennas pick up less signal and thus range and the quality of the connection will be adversely affected. If you are installing a wireless network for your home computer, use a proper PCI wireless card with an external antenna, rather than a USB wireless 'dongle'. This step alone can easily double or more the range you achieve from your wireless network and such cards are often cheaper than their dongle sidekicks.

5. Upgrade your antenna

It's easy to extend the range of a WiFi network by using higher gain antennas on hubs and on PC cards. Changing the antenna on the hub will affect all of the network, whereas changing it on a remote device will affect that device only. Most standard antennas have 2dB gain but 5, 7 or even 9 dB gain antennas can be purchased relatively cheaply. Changing from 2 to 7dB gain antennas will virtually double the range of your network. And if you replace the antennas on both the hub and the remote units with 7dB gain antennas, range will nearly quadruple.
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