MFJ 259's are antiquated!!!
They were great for the time but there are better products out here now. Yes they work, but are quirky to use and eat up batteries.
They are quirky because the tune knob is so touch sensitive that it is hard to lock on a specific frequency and jumps around all over the place even with the slightest touch..
They use 10 AA batteries and drains them fairly quick. These units do have a built in battery charger but it is super slow and you would be better off using an external battery charger.
The 259's are also limited in functions compared to the Rig expert series. Rig experts can do all the functions as the 259' but much more like scanning the antennas bandwidth, R and X,values, even RX values and they can show up to 5 SWR readings at once for multi-band antennas (AA-54 models and up).
I see MFJ recently added a new line of analyzers to compete with the Rig experts that can do many of these functions also.
I have the Rig expert AA-54 which uses only 2 AA batteries and outlasts the 259 by many hours easily. The AA- 54 models in comparison to the AA-30 has the 5 multiple SWR readings and frequency memory storing for fast recall which I like and includes 6 meter analyzing. I now regret not going with the AA-170 which adds 2 meters but maybe some day soon.
As for the AA-600 that the OP mentioned, I can't justify the extra expense over the AA-170 since in a lot of cases, 2 meter and 440 MHz antennas are usually dual band antennas like most mobiles and J-poles for example. Having said that, if 2 meters is showing a good reading, then you should be good to go on 440 on dual band antennas.
Note pic 1 below is one example of what you can do with these Rig expert analyzers.
Here is a scanning example of checking your antennas bandwidth.
In this pic the frequency of the antenna was scanned and shows the lowest SWR at 6.598 KHz at the bottom cursor arrow showing just under 1.2. You can now see the bandwidth of the antenna at a user selectable bandwidth setting which shows here at plus or minus 500 KHz will be an SWR at 3.1.
So here you can see a good usable range of the antenna with a SWR of under 2.1 will be about 200 KHz on either side of the lowest point scanned.
You can move the cursor arrow either direction in this mode to get the exact frequency points to read the SWR value in this scanned region. At anytime you can then press the "ALL" button on the analyzer and get the specifics on what you just scanned and it will look like pic 2.
pic1
pic 2
Try to do all that with the 259's !
As a side note, when I saw what these Rig experts can do, I immediately bought one and sold my MFJ-259b on eBay. Since at the time there was a good demand for those, I had a bidding war and sold it for around $20 less than what I paid for it.
