Yaesu FR-DX400 (= Sommerkamp FR-DX500)
 

I recently got the subject receiver in good conditions. I have =
re-checked everything (including tubes) and accurately tuned it.

It works very well on all band up to 20 meters. On 15 meter and 10 =
meters it works fine, but it is comparatively less sensitive. When =
tuning trimmers and coils one can see a clear signal peak, so it does =
not seem to be a problem bound to a resonating circuit off resonance.

I measured that the signal injected by the conversion crystal oscillator =
into the first mixer gets much lower on the higher frequency bands, but =
I do not suspect a bad crystal as the problem is the same for the =
15-meter band and the four 10-meter segments.

Could it be just a design problem?

I wonder whether someone had a similar experience with that receiver.

73

Tony, I0JX