01-12-2023, 03:59 PM
(This post was last modified: 01-12-2023, 04:01 PM by Mike Watterson.)
(01-12-2023, 03:16 PM)colly0410 Wrote: The asymmetric modulation I was referring to is where the positive part of the AM signal goes above 100% modulation but the negative part doesn't go below 0% as that would be a disaster for sound quality. Read somewhere that Radio 1 used this system for some of their AM transmitters, presume it had a brick wall limiter on the negative part of the carrier to stop it going below 0%...That would be asymmetric distorted audio.
No, what they do is vary the carrier power. The actual modulation stays symmetrical, as mentioned earlier.
In terms of coverage and a Public Service remit, nothing yet actually replaces AM. Closing AM is political more than a question of absolute costs.
Though "bean counters" wanting to close AM to save money, claiming that Streaming, or FM, or DAB or satellite provide the alternative are not looking at true cost vs area served and ease of access (Streaming & satellite may be good "coverage" but poor access), nor running cost for listener. Nor full picture. RTE closed MW long ago claiming no-one wanted it and closed LW RTE1 last spring citing high running costs. These were 0.1% of the top presenters' payments (many are paid via companies as a tax legal "fiddle" and to look better on salaries list). Low hanging fruit for "bean counters". RTE streaming falls over in Ireland if it's anything popular. The only cheap mass market delivery is satellite, but it's not very portable, rarely more than two rooms, rarely without the TV and doesn't actually have the coverage of LW. Tall buildings, valley, trees, apartment not allowed dish or wrong side etc. Still, Irish Bean Counters are technology agnostic, they closed DAB about April or May 2021 citing duplication (the few extra RTE channels, and it only had no local or regional radio) are on DTT (which is about 98% geographic vs 46% geographic for DAB) and Satellite. The main channels that people actually listened to are about 98% coverage on VHF-FM. DAB was costing more than RTE 1 LW, which was also covering most of England & Wales. Interference from Algeria in some areas.
Meanwhile on SW you can easily get Radio China in English.
