Many thanks to SWLing Post contributor, Paul Evans, who notes:
The Federal Register has today published the proposed rule for AM stations to go digital. This is close to the final step.
Comments before 2020-03-09, replies by 2020-04-06.
Thanks for the tip, Paul!
No response.
A Canadian transmitter manufacturer makes both HD radio and DRM models in the MF band. They have high powered models.
Comparison testing should be done at the maximum power allowed ie the equivalent of 50 kW of AM.
Also comparison should also be done where the bandwidth is identical ie 20 kHz which is the bandwidth limit for AM in the Americas.
This being done the effect of skywaves will be significant at night time and affects error correction.
The USA is supposed to be the country of free enterprise.
Why do they use a proprietary system which where a company charges for the use of their technology, in addition to the patents by equipment manufacturers including receiver manufacturers.
Why has there not been any side by side comparison between all digital HDradio and DRM? Before the start of digital TV in Australia the government did a side by side comparison between DVB-T and ATSC invented in the USA. DVB-T will reject reflected signals which are common in the USA where indoor TV antennas we/are common. ATSC cannot reject reflected signals. The result was that the only countries to use ATSC are USA, Canada, Mexico and South Korea!
DRM is not a proprietary system which contains no electricity wasting carrier and has better images ….
DRM will also operate in the virtually empty TV channels 2 – 6 where there is enough channels for all AM and FM transmitters in current use in North America.
> “Why has there not been any side by side comparison between all digital HDradio and DRM?”
There has. You might remember, Alan, that I pointed you to the report, whitepaper, and engineering journal article arising from the first of them (in 2012, IIRC) almost 6 years ago (in March 2014).
For the record, the upshot was that indoor reception quality, outdoor reception quality, mobile reception quality, coverage area, and power requirements were almost identical between HDradio’s all-digital AM MA3 mode and DRM’s mode A protection class 1. (HDradio, of course, allowed ~ double the bitrate due to occupying 20kHz BW vs the 9kHz BW of DRM).
give me a link