Narrow the resolution bandwidth and slow the sweep to remain within the
units calibration requirements. Seems you are simply seeing the noise
of the spectrum analyzer or network analyzer being many dBs below the
reference line. If the unit can tolerate it, increase the RF input
level to keep the notch out of the noise floor of the instrument. I
hope you understand this..
regards
Curt W1FSM
Atlantis wrote:
Hi
In the attached picture you see the notch of the 70cm duplexer I built
according to W4NFR's description in QEX, those who can't receive
attachments find it here:
http://conturafm.mine.nu/_fh/438.95_notch.bmp
The measurement has been made with both cavities of one branch
connected with a true quarter wavelength jumper of RG58 because I had
no double-shielded cable available.
Can anybody tell me why the notch is this blurred and what can be done
about it? The isolation would be a bit better if the notch was a clear
sharp line, isn't it?
Regards
Martin
