In the 3rd paragraph of Reply 3 in the link below, Tim in Bovey reported that he was able to hear a noisy signal from his Part 15 AM station on his car radio at a distance of 7100 feet from the station (1.34 miles away).
He measured the signal strength at that location using a calibrated field intensity meter; it was 60 µV/m.
In other posts he mentioned that the r-f noise level in his community is very low. That would be a factor in getting this kind of range for/with a field intensity of only 60 µV/m.
http://www.part15.us/forum/part15-forums/transmitter-talk/tecsun-pl-310et
Yes, that's why a station goes so good on a car.....only the GE superradio would even come close to that as it has a sensitivity as posted in specs of 65uV/M.
Average radios have sensitivities of about 1500uV/M
Hi-fi tuners are between 500uV/M to 300uV/M generally.
The Tecson model that has the DBu reading, is in the specs 1000uV/M
One of the best moderately priced radios that you can get now that would have decent sensitivities is a few Sangean models and the Grundig S450.
Oh yes Ccrane has one that's supposed to be like the suprradio was.
Mark
"The Tecson model that has the DBu reading, is in the specs 1000uV/M"
Comments...
I own a Tecsun PL-310 with that "dBu" reading. The operation manual for it shows its sensitivity on the AM broadcast band is less than 1 mV/m for a S/N ratio of 26 dB. That audio noise level would be nearly inaudible compared to the program modulation/processing used by most AM broadcast stations.
Using its rather short internal loopstick antenna and inside my home in a city of 42,000, the PL-310 receives the groundwave of radio station WHO from Des Moines, IA -- which has a field intensity here of about 100 µV/m. The audio is noisy, but listenable.
I also have a cheap, >25-year-old, General Electric 7-4624B clock radio in the house that performs about the same when tuned to WHO as the PL-310.
Another old topic revival with few names shown, but you can kind of recognize Richatd Fry's post easily even though his charts didn't survive the sites transfer/crash 7(?) years ago.
This appears to be right around the time I took my first dive into researching part 15 history. Interesting conversation here I thought.