All, my 8405a is set up and almost perfectly calibrated. Due to a
difference in diodes between the probes the sampling efficiency on
channel B is just readable less 'efficient' then channel A. The A
channel is very close to perfect and B has a 2% or so rounded shoulder.
This has an effect but it is limited.
Now my question. An oscillator is setup to feed a tee. To calibrate the
8405a both legs of the tee were set up the same, an identical coupler
and a 50 Ohm terminator on each. The 8405a probes were connected to the
coupler ports. The 8405a was then set to zero phase reading on the 6
Then on one leg the 50 Ohm terminator was removed and replaced with a 2
meter loaded dipole. The frequency was then adjusted to read zero phase.
I concluded this was the zero reactance of the antenna. Is there
anything in error about this conclusion?
At this point the coupler connected to the antenna reads 6 db higher
then the coupler connected to the 50 Ohm terminator. How can the
impedance of the antenna be calculated? A first guess would be about 12
Ohms, 50 divided by 4. This is above the number calculated for the
antenna, but it resting on a less the perfect 1 square foot plate for a
The tee is not a power splitter. What are the possible interference
effects? Should the tee be replaced with a splitter?
Thanks - Dan
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