RigExpert AA-200 Antenna Analyzer
The RigExpert AA-200 is a portable antenna analyzer. It is made in Ukraine, and sold in Europe at a price that is comparable to the well-known MFJ analyzers. In the USA the currency conversion rate does the RigExpert no favours making it expensive compared to its competitors.
On unpacking the AA-200 the first impression is that it is bigger than expected, as the photo showing it in front of my K3 illustrates. It's construction is reminiscent of some of the Russian test gear I used to buy in the '70s. My wife (who is Ukrainian) commented that it looked a bit home made. It is quite robust, but the hard plastic case would probably crack if dropped on to a hard surface from any height. A case is included, which has a neck strap and a clear plastic front so the instrument could be used whilst in the case.
The AA-200 can be used to perform antenna measurements in the range 0.1 to 200MHz. There is another model AA-500 aimed at VHF and UHF enthusiasts that covers the range 5 to 500MHz which has an identical case and uses the same PC software.
Controls and connectors
At the top of the unit is an SO-239 connector for the antenna under test. This will be convenient for most users, but not if the feeder is open wire. If you want to use the AA-200 to measure inductance or capacitance then you will need to make a suitable connector. However it will not be possible to compensate for the connector's own inductance or capacitance as the AA-200 has no facility for calibration. The AA-200 is calibrated at the factory and that's that. I didn't have the facility to test the accuracy of the calibration, but reviews by the RSGB and ARRL suggest that the accuracy is good for an instrument in this class.
At the bottom is a socket for a charger, a socket for a USB connection to a PC, and the on/off switch. The RigExpert AA-200 has an internal rechargeable NiMH battery pack which it is claimed provides enough power for two hours of testing. Battery endurance is longer if the unit is left on standby, but it starts up quickly enough when you switch it on, so it's no problem to switch it off between measurements if you're worried about draining the battery.
The supplied charger (a Ukrainian made wall-wart with Russian two-pin plug, supplied with a UK shaver adapter!) takes 14 hours to fully charge the batteries. There is no cut-off once they are charged, and the manual advises that care should be taken to avoid over-charging.
The main control panel uses a membrane type keyboard, which has a clicky feel and is quite clearly labelled. It is also waterproof, making the AA-200 suitable for use in light rain - the connectors and switch on the bottom being the weak point as far as waterproofing is concerned.
The RigExpert AA-200 is easy to use. In a few button presses and a few seconds you will know exactly how your antenna is performing. You set the centre frequency and the range, then plot the SWR on a graph, directly on the display. By moving the centre frequency using the left and right arrow buttons until it matches the dip in the graph you can determine the exact resonant frequency. Clicking the OK button repeats the test, making it easy to see the effect of any changes. The results of up to 100 plots can be saved to the device's internal memory, and recalled and displayed later.
An alternative graph option lets you plot R (impedance) and X (reactance). Unlike some other antenna analyzers (including the AA-500) the AA-200 can display both positive and negative values of R and X. This option can be used to measure capacitance and inductance, to tune traps and coaxial stubs, measure the characteristic impedance of coaxial cable and locate the position of a short or open circuit in the antenna feeder.
Besides a graphical display you can measure the SWR on a single frequency. SWR is shown digitally, and on a graphical bar meter. Again, you can use the left and right arrow buttons to change the frequency and home in on the exact resonant frequency, the 2:1 SWR points or whatever you are interested in.
Another display mode lets you see all the measurements - SWR, impedance, reactance and capacitance at a particular frequency.
The RigExpert AA-200 has a unique ability to display the SWR on up to five frequencies at a time. This could be handy when making adjustments to a multi-band antenna, though to be honest I haven't used it.
The AA-200 can also be used as a signal generator for test purposes. The output signal has a level of about +10dBm into a 50 ohm load.
Another feature that I haven't tried is the SWR2Air mode. This is supposed to enable you to make adjustments to the antenna when you can't see the AA-200 display. The SWR is transmitted as a tone modulated on a frequency you specify, which you can receive using a portable radio.
The USB socket allows the AA-200 to be connected to a PC, to which it appears as a conventional serial port. Applications for Microsoft Windows are provided on CD with the product. RigExpert does not provide Linux or Mac applications for this product, although a data capture script for Linux has been developed by Andy KB1OIQ.
The AntScope software allows you to carry out measurements controlling the AA-200 from the computer rather than the keypad. The main benefits are a much increased resolution, and graphs can readily be captured to the Windows clipboard from where they can be pasted into a graphics application such as IrfanView and saved in any convenient graphics format. The computer generated charts also allow you to see all the measurements at any point just by running the mouse over the graph.
The LCD2Clip program lets you capture a screenshot of the RigExpert AA-200 LCD display by pressing F+6 on the keypad. The main reason why you might want to do this, rather than use the AntScope application, is to record and print plots taken out in the field that have been saved to memory. But it was also useful to create the screenshots for this article!
Another utility, FlashRWE, lets you save to disk, load from disk or erase graphs that have been stored in the AA-200 memory.
The RigExpert AA-200 is a useful addition to the radio shack, functioning as both antenna analyzer and signal generator. It is easy to use and quick to make measurements which can be captured to computer for reference or printing out if necessary.
The price is right, here in Europe anyway. It's a pity that the application software is only available for the Windows platform, but that won't be a disadvantage to most users.