|Good tool for RF measurements
||Time Owned: 0 to 3 months.
|I have used the MiniVNA Tiny for some RF measurements. I have measured the return loss (S11 or SWR) for HF, VHF and UHF antennas. It does a decent job in my low noise environment. I have measured the common mode impedance of 1:1 baluns, using TL (S21). The results are in good agreement with the same measurements made with a Rhode & Schwartz VNA costing a dozen times more. The utility is very good for the amount invested. Major downside is low power out of the DUT port, with no ability to control the power level. The labeling of the measurements with the associated software is a bit obscure, but I found (using WinZip on the .jar file and Notepad as a unicode editor on the Krause\VNA .properties file) that I could change the labels. So RL is now S11, TL is S21, etc. The signs and numbers now make sense.|
|Not really Lab quality, but alone in its class at 3GHz
||Time Owned: 0 to 3 months.
|The Tiny Works well for its price class, but the OCD posting before this tries to compare it to equipment with less than half the frequency range, which is not fair, |
Its stability is OK if and only if you let it warm up first.
It reaches more than 50 degrees, and should be calibrated at that temperature, NOT when it is cold!
if you do it this way, its stability with respect to impedance is about 2 - 5 percent, repeatable. this is not lab accuracy, but if you forget about that and think of it as an Antenna Analyzer it is very serviceable for all amateur purposes.
0 - 1.5 GHz is more accurate than 1.5 to 3GHz, by the way.
In the lower range it is about as accurate as the competition.
In the high range there IS no competition...
|Needs Stability Improvement
||Time Owned: 3 to 6 months.
|This is a good product, that work wells when it works. The real problem is the stability of the unit. I have access to some excellent VNA Cal Kit loads from Agilent. These loads are perfect. I also have some other decent Cal Loads such as Rosenberger and Suhner.|
The real problem with the Tiny is that its calibration does not hold and cant make repeatable measurements.
You can do a calibration and the calibration looks perfect and the measurements are fine. You shut the VNA/J down open it up and load your CAL file and it reads differently on the same calibration file and load.
The Tiny readings drift all over the place and has no repeatability. I even used short rigid microwave line which is perfect line rated for 26ghz and the unit drifts from 1 minute to another. This is very frustrating when you trying to measure or tune a circuit. Its so bad you can leave the unit sitting there, do a scan, store the scan come back 5 minutes later and the readings will be totally different from the ones that you saved.
While I can understand that the Tiny is not a professional VNA. Its great if you have to tune a antenna or something else, but you can never be sure that what it is reading is correct because of the drift or whatever the problem it has.
In contrast my VNWA can be calibrated and the readings on all the loads are perfect from one measurement to the other. I always let the VNWA and the Tiny warm up for a half an hour.
Another problem with the Tiny is that you cant leave a piece of coax on the Detector port. If you do it seems to affect the readings in reflection mode. You can verify this by adding or removing the cable while doing scans on the test load. It seems susceptible to noise capacitance and environmental coupling. I dont understand why the unit was not built into a shielded enclosure.
I dont know if its the internal clock that drifts or is of poor quality on my unit. I like instrument very much I hope that MRS can improve this great product. I have owned all their products from the original MiniVNA. The Tiny is much better than the extender.
Its one of the best analyzers/VNA around for its broad frequency range. I am mainly using it for testing GSM/3g/LTE antennas and circuits and doing devlopment work in striplines on PCB's. This instrument has potential if it can be improved to be more stable.
|Tiny but a powerful piece of kit
||Time Owned: 0 to 3 months.
|I purchased the miniVNA Tiny as I found my RigExpert AA-600 was limiting me when trying to seriously analyze my system performance. The AA-600 is great for testing locally at the antenna farm but if you need to do anything serious it simply does not cut it.|
The miniVNA Tiny does not have a battery, which is a slight set back, especially if you want to use it in your antenna farm. But, I have to say that this little analyzer is a serious piece of kit if you want to really understand what is going on.
All you need is a laptop, a USB lead and the miniVNA Tiny kit and you are ready to start analysing. You can also use your Android phone, (with a OTG adaptor) which is handy when you are visiting fellow hams or out and about.
The Android app allows you to set multiple plots and scans where the PC software only shows you two. But frankly, the detail is more than enough to get a view of what is going on.
You can save each scan in various formats XLS, zPlot etc. which is ideal for using third party software. Again, something that the AA-600 cannot do.
I now use the AA-600 for setting up the antenna VSWR but use the miniVNA for anything serious. For example, Balun designs or antenna designs etc. You can easily see what is happening and what you need to do to fix the issue.
The best feature in my view is the two port system. You can send out your test signal through the DUT then feed it back into the miniVNA. This allows you to see how the item you are placing in your system is really affecting your line transmissions. For example, Baluns, Filters, Traps etc.
I was planning to purchase the AIM analyzer which is in excess of 1000 pounds. the miniVNA Tiny is just over a third of the price but equally as powerful. Having said that, I have never used the AIM so perhaps I am over stating the point. But nonetheless, a very useful feature.
In short, I am happy with the miniVNA Tiny and use it almost every week on some sort of project.
Antenna analysers are an absolute must in a shack these days. They save you hours of tinkering and allows you to really get a grip on what is happening. To me having the ability to see Z vs VSWR or dBloss plots and then compare phase etc. when needed has really helped my understanding of the unexplainable.
|Great analyzer and VNA, especially for higher frequencies
||Time Owned: 0 to 3 months.
|I only have my MFJ analyzers to compare this to, and I have to say that for antenna analysis, there is nothing like a graph rather than collecting points and entering them into a spreadsheet.|
I have used this to analyze a couple of antenna systems from the coax end. I have also re-measured after tuning a coupler and seeing the results. I had a new appreciation of how the tuner elements are best at a certain frequency, which may be *near* my desired frequency, but not necessarily right-on.
I have also used it as a 2 port VNA, measuring a circuit I had been trying to characterize for over a year, but didn't have the equipment before now, in part because I needed the higher frequency range. I was able to very closely reproduce the results a university got when their engineering department measured the device. The difference could simply be the calibration / measurement plane. Now I can actually re-design the circuit and have measurements to show if I am improving the situation or not.
The Java software has worked on my Linux partition (Debian Wheezy aka 7.1) and on my Windows 7 partition just fine. It takes some getting your head around and the manual is nice in some ways, but has huge gaps, especially if you haven't used a 2 port VNA before! I had to resort to grabbing formulas, some known numbers and a spreadsheet to know the proper way to interpret some values. A couple of sentences in the manual would have saved me the effort, but on the other hand, I learned more this way! There are some glitches in the software, for instance when you save an image of a plot, it doesn't always include the scales, which makes the image much less useful for later comparisons since I have left it to auto-scale.
Overall, I would recommend this device, especially if you need the extended frequency range and can measure from somewhere that you have USB accessible.
1) Connect the device
2) Start the software (need Java runtime installed)
3) Do calibration (it reminds you if there isn't any)
4) Perform measurements
5) Save XML for later analysis or JPG / PDF for an image