The graphics below have been posted here in the past, but newer readers may not have seen them before now.
They contain basic technnical information about the system layout, operation, and performance of various unlicensed AM transmit systems compliant with FCC Part 15.219.
My Panasonic RF-559 says AM sensitivity is 60uV/M for 50mW output which I assume is a listenable station.
The GE Superradio says better than 60uV/M for 30dB quieting.
Typical AM receivers aren't that good so AM reception can be better than a minimum of 150uV/M if you get a better radio.
Canada's BETS-1 says 250uV/M @30meters for AM so a better than average reviever will still get a good signal much further than that.
Here's the Panasonic RF-559
As I put the little pieces together in order to
understand THE SCIENCE of this, I have to
say - - I get a little bit more every time.
Also, seeing the Panasonic RF-559 from
the second post is a real treat. I love
seeing the different vintage radios.
Great stuff.
Brooce
A GE Superadio sits on top of my refridgerator
and runs a lot of the time. (A Superadio 3...
having a Superadio 2 would be nice.)
I was in the engineering shop of WILI 1400
in Wilimantic CT the other day. (WILI has
a great story - for another time, I guess.)
There are three Superadios in the engineering
area that run 24 hours a day. One is for the
1400 AM, another is for their sister FM on 98.3
-- and the third one feeds the AM audio back
to the air monitor line in the AM studio.
Reliable!
Brooce
From Reply #2: Canada's BETS-1 says 250uV/M @30meters for AM so a better than average reviever will still get a good signal much further than that.
It could be further, but maybe not as much further as one might think.
Even for groundwave propagation over a perfect ground plane, a field intensity of 250 µV/m at a horizontal distance of 30m from the transmit antenna would decay at a 1/r rate to 30 µV/m at a distance of 250 meters (0.155 miles) from the transmit antenna.
The Chart shown in the opening post shows too small on my monitor to easily study and read.
Is there a way of magnifying it?
I thought the same thing: try clicking this and then you might have to click the image again when you get there (depending on your browser
In Firefox on a WIN10 PC, right clicking on an image in a Part15us post brings up choices including "View Image." Choosing that will download the image and open it in a new FF tab -- which can be viewed in its original size/resolution.
Probably MS Edge and other web browsers have similar capability, but I haven't checked that out.
Firefox used on a Samsung smartphone will do this, also, when holding a finger down on the image long enough to bring up choices to proceed with.
Two good methods to enlarge images.
Rich Powers, your link did the job.
And Rich Fry, right clicking in Windows 7 also allows enlarging image!
There's always more to learn and we never know enough.
Thank you!
Also, most smartphones allow enlarging a web page or image just by putting a thumb and forefinger on the screen, and moving them apart (un-squeezing them).