Dnia Sat, 29 Jun 2019 21:59:27 +0200, Janusz napisał(a):
> W dniu 2019-06-29 o 09:37, J.F. pisze:
>> I jeszcze ciekawostka - kiedys mi sie radio w samochodzie przestawilo,
>> i musialem ustawiac 0.2MHz wiecej. Jak myslicie - skad taka pomylka ?
>> Maja gdzies ustawiana czestotliwosc posrednia ?
>> Gdzies na swiecie popularne 10.5MHz lub 10.9MHz ?
> Chyba nie bo i po co,

A bo tak.
Na AM bylo 465kHz, 455 ... a nawet
450 kHz, 455 kHz, 460 kHz, 465 kHz, 467 kHz, 470 kHz, 475kHz, 480kHz.


Ciekawa historia
https://en.wikipedia.org/wiki/Intermediate_frequency
#History

An intermediate frequency was first used in the superheterodyne radio
receiver, invented by American scientist Major Edwin Armstrong in
1918, during World War I. A member of the Signal Corps, Armstrong was
building radio direction finding equipment to track German military
signals at the then-very high frequencies of 500 to 3500 kHz. The
triode vacuum tube amplifiers of the day would not amplify stably
above 500 kHz, however, it was easy to get them to oscillate above
that frequency. Armstrong's solution was to set up an oscillator tube
that would create a frequency near the incoming signal, and mix it
with the incoming signal in a 'mixer' tube, creating a 'heterodyne' or
signal at the lower difference frequency, where it could be amplified
easily.

After the war, in 1920, Armstrong sold the patent for the
superheterodyne to Westinghouse, who subsequently sold it to RCA. The
increased complexity of the superheterodyne circuit compared to
earlier regenerative or tuned radio frequency receiver designs slowed
its use, but the advantages of the intermediate frequency for
selectivity and static rejection eventually won out; by 1930, most
radios sold were 'superhets'.


> kwarc Ci popłynął.
> Ja już kilka kwarców wymieniłem i to różnych i 32khz i 11mhz.

J.