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> Additionally, with FM you need to make sure no transmitters on the same frequency can cover the same area, as that would lead to interference. In the UK the

> Additionally, with FM you need to make sure no transmitters on the same frequency can cover the same area, as that would lead to interference. In the UK the BBC transmits their FM channels on the same range across the whole country [0]. In most cases the frequency between transmitters is only slightly different (e.g. 88.5 vs 88.1), so it can be picked up without having to retune the receiver. It requires a bit more thought up front, but it’s not that difficult (compared to other considerations you need to have for tranmitting radio), and it’s a much better UX than having to remember different frequencies for the same station in different cities. [0] http://downloads.bbc.co.uk/reception/pdfs/FMradiotrans.pdf http://downloads.bbc.co.uk/reception/pdfs/FMradiotrans.pdf

lb1lf 9y ago
I suspect (mind, suspect!) that approach wouldn't work here in Norway because of the (generally) different geography; in most of the UK, the main problem would be that you got too far away from the transmitter site for proper reception, in which case overlapping like you describe would work fine. Over here, multipath interference is the main problem with FM - signals bouncing off any number of mountainsides before arriving at the receiver, causing a signal transmitted at time T to arrive at [T+t1], [T+t2]...[T+tn] at the receiver, with no way for the receiver to tell them apart as they are all on the same frequency. Garbled mess ensues. Hence, rather than a few huge transmitter sites, we rely on thousands of smaller sites, the smallest of which used to operate at 200mW, IIRC.
- PoachedSausage 9y ago
  The UK suffers from similar issues, we are not that flat. If you see a map of TX sites like [0] then you will see many small TV and Radio relays covering valleys. [0]http://tx.mb21.co.uk/mapsys/google/alltx.php http://tx.mb21.co.uk/mapsys/google/alltx.php

lb1lf 9y ago

I suspect (mind, suspect!) that approach wouldn't work here in Norway because of the (generally) different geography; in most of the UK, the main problem would be that you got too far away from the transmitter site for proper reception, in which case overlapping like you describe would work fine. Over here, multipath interference is the main problem with FM - signals bouncing off any number of mountainsides before arriving at the receiver, causing a signal transmitted at time T to arrive at [T+t1], [T+t2]...[T+tn] at the receiver, with no way for the receiver to tell them apart as they are all on the same frequency. Garbled mess ensues. Hence, rather than a few huge transmitter sites, we rely on thousands of smaller sites, the smallest of which used to operate at 200mW, IIRC.

PoachedSausage 9y ago
The UK suffers from similar issues, we are not that flat. If you see a map of TX sites like [0] then you will see many small TV and Radio relays covering valleys. [0]http://tx.mb21.co.uk/mapsys/google/alltx.php http://tx.mb21.co.uk/mapsys/google/alltx.php