Technology

59347 readers

5385 users here now

This is a most excellent place for technology news and articles.

Our Rules

Follow the lemmy.world rules.
Only tech related content.
Be excellent to each another!
Mod approved content bots can post up to 10 articles per day.
Threads asking for personal tech support may be deleted.
Politics threads may be removed.
No memes allowed as posts, OK to post as comments.
Only approved bots from the list below, to ask if your bot can be added please contact us.
Check for duplicates before posting, duplicates may be removed

Approved Bots

founded 1 year ago

MODERATORS

[email protected]

167

AM radio listeners set to be permanently tuned out in Japan - Japan Today (japantoday.com)

submitted 5 months ago by [email protected] to c/[email protected]

23 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 3 points 5 months ago* (last edited 5 months ago) (1 children)

I think I understand better where you’re coming from. I have a variety of homemade low frequency antennas, typically on the order of 20 meter wavelength, and I observe lower frequencies clearly get better reception inside buildings. Transmission tends to be more variable because I have an increasingly large near field zone that’s effectively impossible to clear. Indeed, my real world experience has always been the opposite. Lower frequencies appear to get through better, provided you can actually talk out. I usually prefer to modulate the H field because it’s orthogonal to household noise sources and after some distance away doesn’t couple to metal.

I’m not sure why this is. Perhaps buildings are different enough from Faraday cages? Lower frequencies diffract and bend around objects much much more effectively than high frequencies.

I have some RF design engineer friends and I’ll ask them why my experience is different.

[–] [email protected] 2 points 5 months ago* (last edited 5 months ago)

If you find your having better reception indoors then outdoors then the signal your looking for is being attenuated less then the noise/interference is being attenuated by the structure your housing your antenna in.

Low power noise is less likely to bounce around and come in the building from a different angle, but AM is famous for its ability to propagate.

Consider driving a car into a parking structure with the radio on, listening to AM radio. You can hear the signal getting weaker, not stronger. Until you get to the roof. If you go into the basement, you only hear local noise