small rewording oif the original text :
It took just two weeks to restore the transmission quality from the first program of ERA on 88 MHZ, after thenew political party took place in the government. This was the only stationin FM suffering from this problem.
The problem was two fold: background bassy sound plus impulsenoise when heard in DSP radios as Tecsun PL380 and Degen 1126 usingthe same chip . This impulse noise caused by possibly excessive modulationindex causing higher transmission bandwidth tough in my SDR it was shown with typical BW as other stations.
This double problem happened around two years ago but remained for quite long…
Two days agoI received the following reply form an ‘electronics engineer’ :
-Thiscan be a problem with poorly designed DSP and SDR radios
Short Reply:impulse noise is added from the loss of information from filtering a wideband FMsignal.
Long reply:This happened many time to me as engineer on satellite TV antennas when tuningto 36 MHZ poor wide band TV signals . As far you narrow down the pass band, the imagecold from the one side clear from external noise but in same time new sparkles cold beadded from the too narrow signal especially in very intense colors
The samecan happen with the Silicon Labs DSP used in all Tecsun and Degen radios. Itsfilter is quite narrow less than 120 kHz. This is my estimation from my long practice with them older times. I cold receive moderate signals at every 50 kHz.
I m openfor any more discussion on this topic
https://zliangaslogs.blogspot.com/2019/12/era-88mhz.html
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