Post by
Q45tech »
https://forums.nicoclub.com/q45tech-u112.html
Tue Jun 05, 2007 3:13 am
Japan and US [AUS?] use slightly different FM and AM frequency start and stop limits.
"The FM band in Japan is 76-90 MHz. The 90-108 MHz section is used for TV audio for VHF Channels 1,2 and 3. The narrowness of the Japanese band (14 MHz compared to slightly more than 20 MHz for the CCIR band) limits the number of FM stations that can be accommodated on the dial with the result that many commercial radio stations are forced to use AM.
Many Japanese radios are designed to be capable of receiving both the Japanese FM band and the CCIR FM band, so that the same model can be sold within Japan or exported. The radio may cover 76 to 108 MHz, the frequency coverage may be selectable by the user, or during assembly the radio may be set to operate on one band by means of a specially-placed diode or other internal component.
Conventional analog-tuned (dial & pointer) radios may be marked with "TV Sound" in the 90-108 section. If these radios were sold in the USA, for example, the 76-88 section would be marked TV sound for VHF channels 2, 3, 4, 5 and 6, with the 88-108 section band as normal FM.
Second-hand automobiles imported from Japan contain a radio designed for the Japanese FM band, and importers often fit a "converter" to down-convert the 87.5 to 107.9 MHz band to the frequencies that the radio can accept. In addition to showing an incorrect frequency, there are two other disadvantages that can result in poor reception; the converter "compresses" the frequencies making the stations appear closer together, and the original antenna may perform poorly on the higher FM band. Also, RDS is not used in Japan, whereas most modern car radios available in Europe make use of this system. A better solution is to replace the radio and antenna with ones designed for the country where the car will be used."
"Bunbury has a relative dearth of FM services due to the broadcasting of GWN on Channel 3 and ABC TV on Channel 5. These TV channels fall in the FM band and thus no FM radio services can broadcast in the Bunbury license area within the 88-92 MHz and 101-108 MHz ranges. One can receive both TV audio carriers through 91.75 MHz FM (GWN) and 107.75 MHz FM (ABC) respectively. These TV channels will be removed from the FM band once digital TV is mandatory."