"Richard Clark" wrote in message
...
On Mon, 4 Oct 2004 15:19:41 -0500, "John Smith"
wrote:

Here are the results computed from the data:

Freq (MHz) Impedance (Ohms)

410 46.4 + 6.0i (50 Ohm terminator)

380 9.7 - 12.5
390 3.5 - 5.7
400 5.1 + 1.3i
410 5.1 + 6.5i
415 4.0 + 10.0i
425 2.5 + 15.7i

Hi John,

How about the raw data? How about a detailed description of the NARDA
coupler? It should have a calibration plate affixed to the side of it
with freq vs. coupling marks (generally pretty close).

The Narda coupler has no calibration plate. It says model 30611, serial no.
4235. It also appears to have been made for Motorola, as their part number
appears on it. One end says "BTS" and the opposite end says "ANT". At the
BTS end, on the side, there is a connector which says -30 dB. Similarly on
the antenna end.


Raw data:

Reference Measurement
Freq A1 B1 ?1 A2 B2 ?2
415 1 0.76 180 0.82 0.535 158
410 1 0.77 180 0.905 0.57 165
400 1 0.79 180 1.08 0.695 177
390 1 0.81 180 1.02 0.72 -167
425 1 0.743 180 1.06 0.72 145
380 1 0.815 180 0.86 0.485 -151
410 1 0.749 180 0.535 0.029 118
425 1 0.695 180 1.04 0.695 143


I would note you have a considerable SWR, but this was expected going
into the test (however, in an inverse proportion, which may be
meaningful here).

73's
Richard Clark, KB7QHC