RICHARD SOLOMON wrote:
> Now that I have some decent test gear, I would like to do some swept SWR
> measurements of several antennas I have. I have an HP 8350B, but would like
> to get some references to published articles on the subject.
>
> Can anyone point me to something useful I can use ?
HP/Agilent Ap notes? There's one titled something like swept impedance
measurements.
The 8350 is a sweeper, so to do measurements you'll need some sort of
reflectometer and detectors too. A diode detector (or one of the new
Analog Devices chips that has 90dB dynamic range) into a sound card or
the $25 DATAQ data acquisition module might be a good combination.
You hook the sweep sync out from the generator into one input of the
DATAQ, the forward detector output into another, the reverse detector
into yet another, and run the sweeps. Then, use an excel spreadsheet to
turn it all into useful numbers.
You might look at the probe for something like Larry Phipps's LP100
power meter. It has the forward and reverse bridge.
The 8350 has a GPIB/IEEE-488 interface, but most folks don't have a PC
with a 488 interface. There are ethernet or USB to 488 widgets, but
they're in the several hundred dollar range.
The DATAQ is a real handy device for ham fooling around (and for $25,
how can you go wrong)..
http://www.dataq.com/products/startkit/di194rs.htm
4 channels 10 bits, +/- 10V, serial port interface. Lots and lots of
uses. 1 LSB is
There's a $50 USB interface one, too, with 8 channels.
The other inexpensive data acqusition thing is to look for RS232
interface multimeters on sale. They're still in the 0.1% accuracy range
as the DATAQ thing, but they have autoranging, etc. for lower level
signals (e.g. the hundred millivolts from thermocouples, diode
detectors, etc.)
Jim, W6RMK
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|