Re your original question - having both the DG8SAQ VNWA (sdr-kits.net)
and original AIM4170 here are some of my thoughts -
Of course the VNWA can do much more as a two port VNA, has an attractive
price, better RF range, an extremely active yahoogroup, and very
frequent updates to the code, both enhancements and bug fixes. There
are lots of links to helpful references and much discussion about
calibration esoterica way above my pay grade. Kits are no longer
offered. Mine is V2.6 and V3 is current production and various options
are available if getting at the insides are of interest. So, for bench
work it wins for me, partly because the SMA connectors always seem on
the fragile side or require calibrated adapters to RG8 like stuff.
So, for HF antenna measurements, usually I go with the AIM4170, although
I need 12v power for it. OTOH, the VNWA needs USB power and if or
enough power is available from a laptop on battery power is a crap
shoot. The AIM folks have released several updates with bug fixes and
function upgrades. Then again, few laptop screens can be read in
sunlight on a roof or at the top of the tower.
Of course neither can do what a recently "retired" Rhode or Agilent unit
can do, but the weight is about 1/100 and the cost far less than the
simplest repair to either brand. However, as one blogger noted, "the
VNWA should scare the c**p out of Agilent for how well it works".
Keeping a standard coax cable with the calibration plane at the antenna
end helps accurate antenna measurements. In fact, one could calibrate
each coax at time of installation, while still on the ground, and save
the specific cal files (works for either unit).
Last time I wanted to buy MatLab (for some servo work) the cheapest
license was over $1K and I'm not sure for how long. There are ~$100
student versions, but they are tied tightly to courses, proof of
enrollment, and have date expirations, IIRC. There is an open source
competitor SciLab, but I have no experience with it.
On 5/9/2012 8:33 AM, Jim Brown wrote:
> On 5/8/2012 9:01 PM, Jim Lux wrote:
>> what do you want to do with the software? Design matching networks, or
>> just display stuff?
> Design matching networks, primarily with transmission lines.
>> Do you have experience with Matlab?
>> There's a bunch of nice Smith chart manipulation stuff with Matlab (and most
>> of it seems to work with Octave, too)
> Last I heard, Matlab was pricy.
> Thanks and 73, Jim
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