Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: RF Problem Posted: Mon Aug 01, 2005 5:51 pm
Joined: Mon Aug 01, 2005 5:29 pm
I need some help. I have an rf circuit that I believe has a bad
cable or connector. I have taken a Signal Generator to one side of the
circuit and a power meter to the end side. at one end I need to see
a power level at aboiut -27dBM. In order for me to do that I have to
attenuate the signal using an adjustable attenuator. for what ever reason
I can only attenuate the signal to -13dBM. Any furthur and I lose my
signal. If I take a 20dB in-line attenuator to the end of the cable
I can tune the the power level to the desired dB(-27dBM). I even put
a spectrum analyzer to the circuit and saw the freq I need with the
20dB attenuator in line and saw the signal perfectly. When I took the
in-line attenuator out and went straight through, the carrier fell beneath
a noise floor that was not there when the in-line attenuator in the
circuit. Would this have anything to do with a patially cut cable where
there is still center conductor continuity? Or a bad connector?
Post subject: RF ckt behaviorPosted: Sat Aug
06, 2005 11:19 am
What you're describing is a classic non-linear
behavior. In general, you get nonlinear behavior from active devices
(like transistors and FETs) and diodes.
You can unintentionally
create a bad diode if there's corrosion between 2 conductors carrying
RF, but it's more likely that there's a bias problem in your circuit
You haven't given much data on what kind of circuit
you're testing, so the best I can do is the generic vague stuff above.
Is your circuit an amplifier, a variable-gain stage, a modulator, a