[RDXA] Tuning Application for Rig Expert AA-54 (using computer DAQ)

[n2ujn at rochester.rr.com]

All,

A few folks asked me about the computer DAQ capability of the Rig Expert AA-54.  Now that this instrument has arrived, I have explored it's computer data acquisition capability a bit (OS = XP), and, am attaching a graphical application of what is possible.  Incredibly well done hardware and software package for antenna data acquistion and tuning.  

The AA-54, unlike the AA-30, has a modern USB interface at the bottom of the instrument.   The instrument comes with a software disk that actually does not "install" any software per se.   It dumps into a Rig Expert directory a few programs in .exe format; by far the most useful of which is "AntScope.exe".

When RigExpert AA-54 is connected to the computer, and, AntScope is launched, the software automatically locates the virtual COM port generated upon connection (you can find out what it is with another program manually run).  No user configuration necessary.

AntScope is a graphical display, DAQ, and, data export program (.csv, and some others).  You can set the center frequency, and, the range for frequency scan, then, click OK or Run and the DAQ begins.  Takes about 15 seconds to scan (for 101 data points).

At any rate, I have been slowly, with low cost, accessing various HF bands and currently have 10m-17m, + 40m.   

However, at the RARA auction I acquired an MFJ-949C, and, after very little work, and no new parts, the tuner works perfect.  I won't say what the acquisition price was so that the original owner does not ask for it back!

With that, I used RigExpert + computer DAQ to tune the 40m Dipole to the middle of the 20m Phone band.   RigExpert enables live DAQ of a single frequency to do this, then, one can scan the entire frequency range after tuning one frequency.  Minor adjustments can then be made.

Really, an absolutely incredible instrument for getting specific setup with tuning.

Attached is a .jpg of a Matlab plot of the SWR on the 40m dipole, tuner not in line (just the antenna) vs the tuned result using AA-54. This was generated by exporting the two AA-54 DAQ parameters (Resitance and Complex Impedance) as f(freq), then, converting them in Matlab to reflection coefficient rho and SWR (from rho).

So, I now have access (admittedly compromised) to 20m for winter and PSK-31 14.070!!

Without having to build another antenna.   The MFJ inductor setting is only on D out of A-L, capacitors are 2 and 3 out of 6.  So, loss through the tuner is not too bad.   I will actually test on air today.

So, far, the AA-54 exceeds my expectations.  I work with various data acquisition systems and it is rare to have an instrument show up essentially plug and play with truly working hardware, and useful software without doing much work at all to get the results.  

Mike (N2UJN)
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