For a long time now I have had a home-brew antenna analyser based on the VK5JST design. While this has served me OK, the accuracy of the 6m frequency was questionable, as the notes on the side of the tool suggested, and I was really needing something for VHF and UHF with my new interest in satellite and antenna construction.
I had in the past drooled over the Youkits FG-01A, but this again was HF +6m only, and the costs of an MFJ analyser were just wildly out of my range taking into account USD – AUD exchange rates. However we’ve once again seen electronics commoditised over the last few years, and this has led to inexpensive alternatives becoming available. It didn’t take long for the Mini 600, based on the EU1KY design to catch my attention, ticking all the boxes.
After a bit of falling out with eBay, I purchased through Ali Express, which was a new experience to me. Purchasing is a bit unique as you are unable to specify your suburb – it goes by city only. I ended up paying about $330 AUD inc GST + Shipping and once shipped out of China (Ordered 25/12, Shipped 4/1) arrived very quickly on 7/1. This is much faster than my usual China shipping experience.
Surprisingly the Mini 600 is pretty straight forward to use thanks to the touch screen. It did however come with no manual/instructions, and an OSL calibration kit that you have to assemble yourself, again with no manual or instructions. Given that the analyser is calibrated at the factory, I am hoping I don’t need to do this.
There are many ports around the side of the device, including micro and mini USB, SD Card, Ethernet and what appear to be 3.5mm jacks.
Using the STM32 SoC means that a microSD card is used for the firmware. This is notable in the sense that if the SD Card is corrupted in any way, you will need to replace and have the firmware installed. Mental note – make a backup of this card by cloning it!
The majority of the USB ports on the front of the unit are not especially useful and mostly related to the debug I/O of the device and the underlying multi purpose boards. The notably useful port here is the microUSB interface to the left of the Ethernet port, which provides USB access to the microSD card, that stores snapshots on.
Speaking of snapshots – when you save your results, they are stored as a .bmp picture and a s1p touchstone file type. The latter can be imported into a number of applications freely available to plot an analyse.
I have quickly put it into use to finally measure a couple of yagi antennas I purchased at an estate sale, purporting to be for 2m and 70cm bands.
Things don’t look good for the 2m antenna, which it being clearly resonant in the VHF “High Band” land mobile frequencies at 154Mhz. This would mean longer elements required, and will not be worth the effort compared to building new.
Things look better for the 70cm antenna, which clearly has better resonance in the transmit side of the 70cm band, however the SWR is a little high. That may be due to the way I was connecting to the antenna or the condition of the antenna itself, having been exposed to a coastal environment.
How about my recently built satellite antenna?
On 2m, the plot is fantastic and everything that was to be expected. 70cm is a slightly different story:
While the SWR of 2.3 and approaching 3.0 is not terrible, it’s definitely not great either, when the original design indicates the SWR at 436.5Mhz should be closer to 1.1. Re-measuring the elements suggests that I may have element 5 of the yagi in the wrong location, with the driven element being slightly out as well. Further investigation will be required.
The mini600 is capable to work as a 01-600Mhz frequency generator along with a time domain reflectometer. I have not gone into the frequency generator in this post, as it’s not why I bought the device, but the TDM was interesting enough to take a look at.
Using a spare piece of LMR400 I have for portable 23cm operations, I plugged it in and did a scan. The device did what it says it would, and I am not really sure if there is any more to say on that!
The Mini 600 seems to be quite a capable device for the budget conscious hobbyist and will for the most part provide accurate enough information for most users. This kind of technology would have well and truly been in the thousands of dollars a decade ago, so having this as an affordable option now is quite fantastic.