ARLA/CLUSTER: Short-Wave.INFO fundamental para quem escuta emissorasem Onda Curta

Quinta-Feira, 31 de Outubro de 2013 - 15:58:32 WET

Uso-o hÃ¡ bastante tempo Ã© mesmo muito bom.

73 de JosÃ© LuÃs ProenÃ§a, Operador do Posto Emissor CT1GZB
ARVM # 53
REP # 1418
SKCC # 8178
CT-QRP # 058
NRA # PN 077
http://ct1gzb.blogspot.com

From: JoÃ£o Costa > CT1FBF 
Sent: Thursday, October 31, 2013 12:25 PM
To: Cluster-ARLA 
Cc: radioamadores_algarve  yahoogrupos.com.br ; ct-comunicacoes-e-tecnologias  googlegroups.com 
Subject: ARLA/CLUSTER: Short-Wave.INFO fundamental para quem escuta emissorasem Onda Curta

What is Short-Wave.Info?
Short-Wave.Info is a simple way in which to interrogate a database of all the short wave broadcasts being transmitted by the majority of the world's international radio stations. There are two ways in which this vast database of frequencies can be queried: 
  a.. you can select a language and/or a particular broadcaster; or 
  b.. you can select a specific frequency. 
In either case, our sophisticated search software will return a series of results (unless, that is, there were no results matching your query). This software is designed to allow listeners to quickly find the frequencies to which to tune as well as permitting stations being received to be easily identified. Note: You can click on any frequency, language or broadcaster shown in the results of a search to begin a new search. 
Selection by Language and/or Broadcaster
Where a language has been selected, all the broadcasts on-air in that language will be shown. A list of the frequencies used for these broadcasts along with the particular radio broadcasting station concerned will be produced, and a map showing the location and frequency of every transmitter on-air will also be produced. Similarly, if a specific broadcaster has been selected, all transmissions on-air by that broadcaster will be shown. Where both a language and a broadcaster are selected, all the transmissions by that broadcaster, in that language, will be listed, whether on-air or not. Any which are on-air at the selected time are highlighted (in red) and a map of these transmissions is produced. 
Selection by Frequency
If a frequency is selected, all broadcasts on that frequency and (optionally) within plus or minus 10 kHz of that frequency will be shown. Any on-air at the selected time will be highlighted and a map of their location produced. 
Interpreting the Results
Your search for short wave broadcasters will result in a map showing the location of any stations on air at the time you selected (normally 'now' but you can select your own time - note that all times have to be in GMT/UTC). In addition, the results will show a table like the one below. Freq â–¼ Station  Start  End  Days Language  Pwr Az Transmitter Site  Lat/Long  Remarksâ—† 
      9430 BBC 18:00  21:00  1234567  English 250  170  WooffertonBearing: 262Â°
      Distance: 1092km 52N19 002W43  BBC b11 
      9460 BBC 03:00  04:00  1234567  English 250  280  MaheBearing: 153Â°
      Distance: 7476km 04S35 055E28  BBC b11 
      9490 BBC 15:00  16:00  1234567  English 100  15  MeyertonBearing: 170Â°
      Distance: 8909km 26S34 028E07  BBC b11 
      9505 BBC 15:00  17:00  1234567  English 300  97  LimassolBearing: 147Â°
      Distance: 2527km 34N43 033E19  BBC b11 
      9505 BBC 17:00  18:30  1234567  English 250  315  KranjiBearing: 142Â°
      Distance: 9904km 01N25 103E44  BBC b11 
      9660 BBC 22:00  23:00  12345..  English 10  10  BrandonBearing: 144Â°
      Distance: 14625km 19S30 147E20  BBC b11 
      9915 BBC 21:00  23:00  1234567  English 250  65  AscensionBearing: 198Â°
      Distance: 7215km 07S54 014W22  BBC b11 
      11760 BBC 07:00  14:00  1234567  English 250  320  Al SeelaBearing: 142Â°
      Distance: 5167km 21N57 059E27  BBC b11 
      11895 BBC 09:00  10:00  1234567  English 250  45  Nakhon SawanBearing: 141Â°
      Distance: 8461km 15N03 100E03  BBC b11 
Frequencies which are currently on-air are highlighted in red. If the frequency has a 'zig zag' behind it (as for 9460 kHz in the example above), this indicates that there is the possibility that this transmission is being jammed and that reception may not be possible. A signal strength bar shows on the right of the table if the transmission is on-air, to indicate how likely it is that you can hear the station. There are more details on how the signal strength indicator works and what it means. 
Hints and Tips
Frequencies above around 9 MHz (9000 kHz) will travel across areas of daylight reasonably well. Frequencies below around 12 MHz (12000 kHz) will travel across areas of darkness well. (It therefore follows that frequencies between about 9 and 12 MHz will travel across areas of both darkness and daylight). The map produced by the software shows the location of on-air transmitters and shades the parts of the earth currently in daylight and darkness.

If the area in which you are located is currently in daylight, the best reception is likely to be from transmitter sites which are also in daylight and which are on frequencies over 9000 kHz. If you are in the area which is currently in darkness, look for transmitters which are also darkness and which are on frequencies below 12000 kHz. There is more information on how short wave propagation works if you want to understand this better. 
Examples
You are having a friend from Turkey over to stay and want to let them be able to listen to the news from home. One option would be to select 'Turkish' as the language from the pull-down menu and then click the 'GO' button. This will provide you with a list of all broadcasts currently on-air in Turkish. If you wanted to select a particular time, unclick the 'NOW' button and enter a time (in GMT/UTC) into the boxed. Alternatively you might choose to select 'Voice of Turkey' from the station list. You could even do both and select 'Voice of Turkey' and 'Turkish' - this will show you a list of all the broadcasts from Voice of Turkey in Turkish, highlighting those currently on-air.

You are tuning around on your short-wave radio and hear a station on 9870 kHz. You then type '9870' into the frequency box and click the 'NOW' button. This will produce a list of all the stations which broadcast on 9870 kHz or on frequencies within 10 kHz of it, and highlight those currently on-air. As long as you can identify the language being broadcast, you can then find out what station you are listening to! 
Bearing and Distance
Short-Wave.Info now provides information on the distance and bearing that a short-wave transmitter is from your location, as long as we can work out where you are! Your location is initially provided by a service called hostip.info. If they can work out where you are, or someone else from your IP address has registered a location, a green dot () will appear on the map of the world. If we have your IP address but can't work out where you are, a red dot () will be shown instead (at 0 degrees East, 0 degrees North!) The hostip (and the short-wave.info) database are not always correct or complete. If your location is either wrong, or a red dot appears, you can correct the location. Just click on the dot and drag it to the location on the world map that corresponds to your location (note that this does work with tablet computers but is not as smooth or reliable as with desktops). You will be given the option to select this as your location. If you do, the short-wave.info IP look-up database will be updated and next time you select a frequency or station, the location shown will be that which you selected.

If your location can be ascertained, two pieces of additional information will be provided. If you hold your mouse over the list of transmitter sites, the bearing and distance (in kilometers) from you to the site in question will be given. Try it on the examples above (note that this is only an example, and the distances and bearings to the transmitter sites are not accurate). 
Signal Strength Indicator
If your location is known, you will also notice that in the right hand column of the table is a signal strength indicator. This goes from no bars (meaning the station is off-air) to five bars. Given the vaguaries of short wave propagation no system can be completely accurate, however a unique short-wave.info algorithm has been used to try and give an indication of the probability of being able to receive a particular transmission. The different numbers of bars represent different probabilities of reception which roughly translate as:
     It is highly unlikely that you will be able to receive this transmission.  
     In favourable conditions, you may just be able to receive this transmission.  
     Your chances of receiving this transmission are roughly 50:50.  
     There is a reasonable chance that you will be able to receive this transmission.  
     Under most conditions, you should be able to receive this transmission.  

Obviously much depends upon the quality of your receiver and your aerial, as well as whether you are listening in a noisy suburban area, or a quiet rural area. It is also worth noting that no account is taken of whether or not there may be interference on the same frequency. If another station is broadcasting on the same frequency but with a higher probability of reception, then the chances are you will hear that instead! 
How does it work?
The algorithm which calculates your chances of reception uses many factors to try and give a reasonable estimate including: 
  a.. the distance and bearing from you to the transmitter site and of the transmitter site to you; 
  b.. the time of day at both your location and that of the transmitter; 
  c.. the power of the transmitting station; 
  d.. the type of transmitting antenna it is using; and 
  e.. the frequency on which the station is transmitting. 
All these factors are fused together in a complex calculation which models the path between you and the station and the likely conditions to yield the resulting probability. It is not 100% accurate (indeed if it's better than 50% then it's doing well!) but is at least useful in providing an indication of whether or not a station might be audible. 
Changing The Order
By default, the results of a search are shown in ascending frequency order. It is possible, however, to re-order the results. To the right of the 'Freq' and 'Remarks' columns, a triangle (â–¼) or a diamond (â—†) symbol are shown. Clicking on these will re-order the results. Clicking on the symbol next to 'Freq' will re-order the results in frequency order. Clicking it a second time will re-order the results in reverse frequency order. Clicking on the symbol next to 'Remarks' will re-order the results with the strongest predicted signal first. And, of course, clicking it again will reverse the direction. Please note that as the signal strength prediction algorithm is not 100% accurate, sorting in signal strength order may equally not prove 100% accurate. 
Acknowledgements
We are very grateful for the work of Aoki for compiling the database which is used to generate the maps and lists on this site. If you have any updated schedule information please contact Aoki so that the database can be kept as accurate as possible. 
Contact
If you have any comments about this web-site, please send an e-mail to comments  short-wave.info. 

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