Radio/Band/Expanders

RADIO BAND EXPANDERS

We hold in stock mant types of radio band expanders to convert japanese radios to New Zealand frequencies, we carry 10Hz / 12Hz / 14Hz / 16Hz and 18Hz models and these can be installed into your vehicle at your location.

The Car Stereo is the second most important accessory in a modern car today next to a good alarm / immobiliser, and we all know how frustrating it can be when your Radio has "Bad Reception" and does not work properly.

This is doubly difficult to achieve when shifting radio frequencies from 88 - 108Mhz to 76 - 90Mhz as there are a number of problems to overcome.

As you can see International FM Band's bandwidth is 20Mhz ( 88Mhz-108Mhz) compared to Japanese FM Band's bandwidth only 14Mhz wide ( 76Mhz-90Mhz ).

Larger bandwidth means a larger number of FM stations, so converting entirely International FM Band to Japanese FM Band must contain some compromises.

All FM Band Expanders available on market are comprised more or less to accomodate frequency shift.

Unfortunately there are a number of manufacturers claiming that their products are superior. By the use of SMD technology, amplification, coaxial leads and the use of RT filter unfortunately not necessary tuned to the frequencies required resulting in poor reception performances .

Manufacturers will even give technical specifications obtained goodness knows how, to proof how well their Band Expander works, and the quality of their components which may or may not improve the performance of their Band Expanders, obviously you must install units with best possible components if not there will always be a problem with inferior componentry.

Each manufacturer will always want to state that they have the best all around unit available, of course without Professional technical specifications and trying the Band Expander in a vehicle is the only and proper way to confirm which Band Expander is the best.

First necessary compromise common to all FM Band Expanders are blank-spots on frequency tuning range, caused by frequency harmonics generated by Crystal oscillator operating well below receiving Frequencies. ( Please click link above to see examples)

Second necessary compromise common to all FM Band Expanders are radio stations double-ups, caused by shifting 20Mhz bandwidth into 14Mhz bandwidth ( 88Mhz-108Mhz shifted into 76Mhz-90Mhz) and overlapping Japanese FM Band and International FM Band ( 88Mhz-90Mhz). ( Please click link above to see examples)
As you can see it is important to work out which frequency shift option suits your requirements.
Recommended starting point is to try to use Worldwide models, but if double ups are not acceptable, use Specific area models which have smaller bandwidth. We can provide you the suitable frequency shift option for your requirement . Please supply us, all your local radio station frequencies. We will run a program working out best suitable Band Expander.

Third necessary compromise common to all FM Band Expander's amplification of desired FM Band frequencies which limits conversion gain to prevent car radio's tuner oscillating.
When tuner oscillate, reception is unpredictable. ( Amplification must be set to tuners tolerance, not to high or to low.)

Radio Telephone filter or Blocking Filter is essential requirement in rejecting unwanted frequencies interfering with the shifted FM Band. Unfortunately most countries frequency range is fully utilized, resulting in large numbers of Communication Equipment operating above and below FM Band. Compromising filter's performance will result in more interference occurring.

There are two ways to manufacture FM Band Expanders first by individually assembling and tuning unit to precisely set it's performance parameters and secondly by masproduction which has its benefits in cheaper labour cost but unfortunately performances can not necessarily be guaranteed. For example Cheap Car Radio's tuners in comparison with more upmarket ones are manufactured for masproduction and require no tuning to precisely set it's performance parameters.
By installing a pore performing Band Expander to the front-end ( tuner) will alter tuner's performances resulting in converting an upmarket car radio into a Budget Car Radio.

After all Band Expanders are probably the only Band Expanders available on market manufactured by individually assembling and tuning each unit to precisely set it's performance parameters on appropriate RF test equipment.