Would FM HD Have Worked Better In Ireland?

The American IBOC/ 'HD' puts digital signals surrounding the analogue FM signal so both combined takes up a bandwidth of 0.4MHz

IBOC/'HD' digital radio is much less workable in Europe than in the USA due to different RF planning. Their FM band is channelized in 0.2 steps (0.1 steps here) so obviously you will not get two stations receiveable in the same area 0.3MHz apart over there - If they were running 'HD' they would interfere with each other and the HD probably not work at all for both stations.

There are many cases of overlapping coverage of transmitters for the same station (identical audio) which are 0.2MHz apart such as 100.3/100.5 in Dublin. HD would be utterly unworkable there.

As it is, HD in the USA, building penetration is poor, the FM-mono service area is hugely greater out into rural areas than the HD is. It wipes out with 'white noise' reception of distant FM stations (adjacent frequencies to local stations with 'HD') that high selectivity receivers would otherwise be able to receive.

Digital radio skeptics would agree that DAB is a lesser evil than the American 'HD'/IBOC

@Antenna has given good technical reasons as to why the Hybrid-Digital Radio standard would be very troublesome to operate in Ireland, but to give my own €0.02, it would be economically impractical for HD Radio (at least its VHF/FM version) to be introduced into Ireland and being the only European country to actively do so (AFAIK the only country outside of the North Americas to adopt it is the Philippines) and nobody is going to make HD-Radio compatible receivers exclusively for the Irish market. If the French, whom originally mandated T-DMB for digital radio broadcasting, had to end up changing to DAB+ because no one else in Europe was going to copy them, then no one else in Europe is going to try and go it alone either on going with DAB+ or maintain FM (while mostly phasing out MW/LW) for the foreseeable future.

There were a few HD-Radio VHF tests a number of years back in Switzerland & Romania but nothing came off them (indeed the Swiss have gone balls deep with regards DAB+, an FM switchover there seems likely in the short-mid term).

The North American FM band is not as closely coordinated than the one in Europe. For instance in North America, there is no 100 Mhz, only 99.9 and 100.1, thus there is more space in between.

I am only aware of one European country where there is HD radio on air, and that is in Romania.

HD radio uptake is way way less than DAB / DAB+ in Europe.

The band whichis used for DAB / DAB+ in Europe is used by the military in the US, - and Canada simply went along as well.

Those who are so against DAB/DAB+ in Ireland today will most likely have passed away in 10 to 15 years or will be a small minority. FM is simply not fit for the future, as it's too expensive in transmission cost, plus the listener of today expects a lot more choice, - one only can find either on a smart phone or on DAB+.