No subject
Thu Feb 21 15:38:05 EST 2013
scale on the VM where probably blowby or extraneous rf is being read by =
the VM. This gives me about a 50db range I can use to test the filters, =
which may be good enough to start.
Can someone help me with increasing the range I can measure or is there =
a better way to set up this arrangement? I do have another RF voltmeter, =
an HP410D but it reads much higher voltages than the mvolt meter. I also =
have some various amplifiers I could use on the output of the filter, =
but they are all 50 ohm input devices.
This FA filter I am testing seems to be working, it was one sent to me =
and the bobbins were loose and a wire broken. I only replaced the =
bobbins and repaired the broken wire and it seems to be working as a =
real 2k filter, but I haven't made detailed measurements on it until I =
feel confident with the test set.
I have another FA filter that measures good with the ohmeter, 50 ohms in =
and out, and good ground with no perceptible feedthrough to ground, but =
that filter is just not working. These filters would work fine in a =
R390A filter tube if the mounting stud is cut off and the unit mounted =
in the tube. If this filter works satisfactorily, I'll try that since my =
2K filter seems a lost cause at the moment.
http://i251.photobucket.com/albums/gg287/DogTi/R390A/testset_zps70751df1.=
jpg
More information about the R-390
mailing list