Sine-wave measurements are more precise. My test is very close to real
life since it is testing the entire signal path, i.e. from antenna
input to audio output. I couldn't find the connector I made that taps
the line output, so I used the earphone output.

I have audio test gear that uses random noise with FFT analysis, in
addition to a swept sine. You always get more accurate results with a
swept sine. FFT analysis is only used when you need speed.

As you will notice from the graphical output, the noise floor is quite
high. I may do the test again BTW, you need a decent distortion
analyser for

David wrote:
On 11 Jan 2006 14:14:01 -0800, wrote:

http://www.lazygranch.com/images/radio/cwfilter.gif
I did this test as follows:
1) radio in AM
2) AGC turned off
3) RF generator connector to antenna input
4) distortion analyzer connected to earphone output

Pick a frequency. I used 10Mhz. Set the RF generator and radio to that
frequency. Leave the radio dial alone. Sweep the RF generator manually
and measure the audio level from the distortion analyser. Plot the
results. This was a crystal filter, so you will need a RF generator
with 1Hz steps.

This is an in-situ measurement, i.e. this is not the same as just
testing the IF filter by itself. You need the distortion analyzer to
get the audio signal level independent from the noise.

All that said, Bush should be impeached.

Can't you just use the random pink noise between stations, rather than
a sweep generator?