Digital Dividend from radio stations?

[Ockie]

Hi guys. Sorry for posting this here....but dont know where else to post.

Last night I was wondering....we are migration our terrestrial TV signals over to digital and this will free up spectrum for our mobile operators...but what about radio stations? Will those be migrated also and can the frequencies that they currently broadcast in also be used by mobile operators or is FM not compatible for GSM use?

I am just curious. I have seen some of you guys are rather clued up on this sort of thing.

 

[bsntombela]

Hi guys. Sorry for posting this here....but dont know where else to post.

Last night I was wondering....we are migration our terrestrial TV signals over to digital and this will free up spectrum for our mobile operators...but what about radio stations? Will those be migrated also and can the frequencies that they currently broadcast in also be used by mobile operators or is FM not compatible for GSM use?

I am just curious. I have seen some of you guys are rather clued up on this sort of thing.

A friend of mine works for the SABC and has been testing their "digital decoder thingy" for the past two years. It works like your existing DSTV decoder, i.e. You have bouquet for television and a radio channels bouquet. As far as use on GSM networks, have no clue!

 

[JimM]

The FM band runs from 88MHz to 108MHz and that gives a total of 20MHz bandwidth

The 900MHz cellular band runs from approximately 890MHz to 960MHz and thus a bandwidth of 70MHz

Assuming you could vacate the current FM band within a decade or three, 20MHz isn't going to provide many cellular channels! Plus you would need to transmit and receive simultaneously within the 20MHz available so some serious filtering would be required!! Your handset would probably end up rather large because of the filters required at centre band of 100MHz and the antenna size would also be around 0.75 meters in size!

 

[Ockie]

The FM band runs from 88MHz to 108MHz and that gives a total of 20MHz bandwidth

The 900MHz cellular band runs from approximately 890MHz to 960MHz and thus a bandwidth of 70MHz

Assuming you could vacate the current FM band within a decade or three, 20MHz isn't going to provide many cellular channels! Plus you would need to transmit and receive simultaneously within the 20MHz available so some serious filtering would be required!! Your handset would probably end up rather large because of the filters required at centre band of 100MHz and the antenna size would also be around 0.75 meters in size!

oh

It is amazing to think the range of the spectrum and here we are trying to find space for mobile operators. I wish we were in the Star Trek movies where our Blackberries can transmit via sub space bands! urg Then we can give ICASA the finger!

 

[JimM]

When 700MHz becomes free this will be a super band for cellular use and at least 100MHz should become available! Plus signals penetrate buildings where 2100MHz (3G/UTMS) do not. Anything lower than 500MHz would be impractical due to antenna wavelength (usually the antenna is one quarter of the wavelength in physical size) and filtering as simultaneous transmit and receive must be done in band, once you go below 500MHz these filters would become quite big!

The allocation of cellular frequencies to operators (for use) is the responsibility of ICASA but the frequency bands themselves are determined by the ITU of which ICASA is a member but they can not alter the band (channel allocation) locally.

There are many spare frequencies available but sadly not below 2500MHz and as we've seen with 3G on 2100MHz it is not that great! China is already using 2400MHz but I've no idea how well its operating?