I have been using AM radio receivers for a long time but I have encountered fading many times while listening to the SW reception. However, I have noticed that the most expensive radio receivers from Tecsun, Degen, and Sony minimize fading up to certain extent. So, why does it happen? Is it something to do with the AGC or the sensitivity?
I would also like to know whether an AM radio that uses vacuum tubes instead of transistors, can have a better reception quality?
I have been using AM radio receivers for a long time but I have encountered fading many times while listening to the SW reception. However, I have noticed that the most expensive radio receivers from Tecsun, Degen, and Sony minimize fading up to certain extent. So, why does it happen? Is it something to do with the AGC or the sensitivity?
Both, if it's more sensitive the AGC will turn the gain down, giving it more range to turn it back up as the signal fades. Better radios are more likely to be more selective as well, particularly proper communications receivers which are likely to be much better performers all round (there are reasons why they cost so much).
It 'can', but it's unlikely to - though certainly an expensive well designed valve receiver will out perform a cheap transistor one - but a well made and well designed modern transistor receiver should outperform any valve receiver (other than in the case of a Nuclear EMP ).
Many thanks to SWLing Post contributor, 13dka, who shares the following guest post: Revisiting the Belka’s “pseudo-sync detector”: A sync detector crash course! by 13dka “It…