Thank you very much for all your replies. I was very happy to detect an
image signal at 630 kHz of a powerful 1530 kHz station on another
single-conversion radio (RadioShack DX-375). Note, that it was 630 kHz on
DX-375 instead of 620 kHz on Tecsun PL-230. It means that the intermediate
frequency for DX-375 is 450 kHz, for PL-230 it is 455 kHz. There was no
image signal for this 1530 kHz station on a dual conversion radio
ATS-909/DX-398. However, ATS-909/DX-398 detects an image signal at 240 kHz
(long waves) for the powerful 1140 kHz station. I was surprised for a long
time why I can hear radio stations on long waves in the US. I have found
an explanation for this. Thanks again.

-Alex

On Sat, 20 Aug 2005, Dale Parfitt wrote:


wrote in message
...
Shortwave radio is actually AM radio.
cuhulin

I have no idea what that means, but thanks Pete KE9OAfor supplying the
proper math to answer the original poster's questions.
Answers like:
"Nothing wrong with it. That's how single conversion superhet radios
work."

Do nothing to illuminate the solution or why the problem exists.
Dale W4OP