What would be the practical difference in range between using, say, 1650KHz and 1570KHz (if any)? I would like to pick up the AM signal on vintage type radios (only going up to 1610KHz), but want to get the maximum range possible (and 1570 is the clearest frequency under 1610).
Hello ArtisanRadio
I use 1550 and 1640 KHz, and if there's a difference in distance, it's probably a matter of inches. It's too close to notice.
When I used 960 KHz the range was very much less.
Having also used 1060 and 1160 KHz the results where as you'd expect: better than 960 but not as good as those extended band channels.
One factor that will matter is background stations, which can reduce the effective distance.
.
My experience agrees with Carl's. I changed from 1520 to 1670 kHz and didn't notice any change in range. Both frequencies are quiet during the day but 1670 is quieter at night, thus the change. I did returne the antenna when I QSYed. (QSY means change frequency). For use with your in your home antiques night background interference should not be a problem if you find a reasonably quiet frequency. Here, I use a 1936 vintage Crosley tombstone style radio now and then just for fun but I tweaked the trimmers on the tuning caps so it receives at 1670 kHz. Maybe that's more than you want to try.
Theory would predict that the efficiency of a short length limited antenna is higher at the higher frequency but, as Carl pointed out, and it is confirmed from experience, this difference is of no practical benefit for the small frequency changes we are mentioning around 1600 kHz.
Keep in mind that the other frequencies Carl mentioned are very much lower percentagewise than the frequencies you are citing.
Neil