Tuesday, August 03, 2010

MiniVNA Pro first impressions

A new toy arrived today, a MiniVNA Pro.

minivna.jpg

It's a very nice bit of gear and comes with calibration loads.

I've failed to get it going reliably on my primary machines, MacOS X and Linux so for now I'm using it on a Window virtual machine.

After calibration I connected up my 40 and 80m dipole antenna (both in parallel) and it gave me this wonderful SWR plot in about a second:

swr.png

It also produces a Smith chart but I don't know how to interpret it.

smith.png

It's astonishing that a home constructor can own test equipment like this.

I have much to learn.

Update: Now working under Ubuntu

The software for linux is a java application vna/J

The trick is to use the serial library installed like this: apt-get install librxtx-java

Here's the calibration dialog:

And here is the resistance of a 50 ohm terminator swept up to 180Mhz.

Here's a sweep of a 3.6864 crystal.



Very cool.

Update: Now working under MacOS X

I grabbed a copy of the rxtx library from here that works 64bit and copied it to /Library/Java/Extensions/ but as soon as the software tries to use the serial port, like during the calibration run, I'd get "VNADriverSerialPro::init() gnu.io.PortInUseException: Unknown Application".

The trick, thanks to this page, is:


sh-3.2# mkdir /var/lock
sh-3.2# chmod 777 /var/lock


Now everything's fine.

minivna mac.png

8 comments:

Alan Yates said...

Very nice Peter, that should let you do some detailed antenna experiments, and filter work!

Have you tried the Bluetooth remote feature of the Pro yet?

Peter B Marks said...

Bluetooth works nicely. You have to open it up to connect the re-chargeable battery and then charge for a while via USB.

I'm very happy with the device.

Anonymous said...

The Mini VNA Pro is a good idea
but the implementation is crap to be generous documentation crap you must be well paid for the propaganda

Peter B Marks said...

Strange comment. Let me assure you that I paid full price for the MiniVNA and am not paid for favourable reviews.

Can you be more specific about your criticism of the device?

Unknown said...

Peter,

Thanks for the post.

I think that people that are (too) critical have zero experience with 2 port network analyzers. Plenty of info on the internet for those that need to ramp up on this to be able to understand what a Vector Network Analyzer does.

After having worked with all of the industry heavies, I find this device to be a breath of fresh air.

73's,
John W.
KJ6HCV

Anonymous said...

Well, had it for a half year now, despite few drawbacks, its more than average joesixpack will ever comprehend... leave alone how to use it. But to the point, it occured to me that with appropriate software unit can be adapted for surrogate panadapter, if not complete SDR. Due to the lack of any REAL documentation it still somewhere in the clouds for now. But any comments will be welcome...

M1GRY said...

Peter, your screen grab of the calibration seems to indicate a problem. I see that you have done the short/open/50ohm. Two of the parts look ok - the smooth curves, but the first one looks the same as mine when it isn't working correctly!

Peter B Marks said...

Thanks for the tip. I'll go back and give it another try.