RG-59 is 75 ohms. You want to use some 50 ohm?cable (RG-58)?for
your jumper. Your BNC T with a 50 ohm termination will introduce some VSWR to
the measurement. Use a 50 ohm through adapter for the best result. Or, you could
place a 20 dB attenuator in place of the through adapter.
?
Tom
?
?
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----- Original Message -----
Sent: Friday, January 25, 2013 10:41
AM
Subject: [TekScopes] Scope
bandwidth
?
Hi all,
I have a Tek 2235. Its -3dB bandwidth specification is "DC
to at least
100MHz" when using the 5mV/division to 5V/division vertical
scales.
For no particular reason, I decided to verify that
specification. I
connected an HP8657B signal source to the CH1 input with
a 36in RG59
coaxial test lead and used a BNC-tee to terminate the scope
input with
50 ohms. Then I made some measurements using 0dBm at 1MHz as
the
reference. Using this method, the -3dB point is about 20MHz on both
CH1
and CH2. It's down about 24dB at 100MHz.
I was expecting the
-3dB point to be at least 100MHz. Is my methodology
flawed? Do I have a
bad scope?
Thanks.
Steve
