RigExpert or NanoVNA - Checking 1/4 Wave Coax Stubs  

I also have the AA-55 Zoom. I was hesitant given the price but it's a fantastic piece of kit that simplifies so many routine tasks. Y

Bought the AA-35 from W&S today. The only thing missing from my arsenal.

I have to agree with your findings in that the Rigexpert is quicker and easier to use, particularly out in the field. I have a RE AA600, not quite as versatile as your AA55 zoom but I wanted VHF/UHF coverage. I recently purchased a SV4401A VNA. It's a new model with much bigger screen, large internal memory for calibration/screenshot storage etc and way more functionality than the RE and in a similar price bracket so quite a bit more expensive than a Nano VNA. Comparing the two on various measurements I've found them virtually identical after calibration and so far I'm very pleased with it.

There is a Rig Expert free down load and you can connect via a usb cable to your computer and your RigExpert and shows a sweep graph across the whole range and giving reactance and SWR and so on.

You didnt do yhe calibration wrong. You just used to large of a sample range. 30 to 35 is a big gap to cover to target a specific point such as yhe one you were looking for. The result you received was the closest sample point that returned a value. You could have taken that point and reduced your scan range around it and rescanned and it would have brought the point closer to where it should be. The AA-55 does the same thing with the zoom function.

My test with a rig expert showed that the so239 adaptor is included when you neasure length (2 cm)

FYI Next time use a OSL PL259 calibration standards on the Nano pigtail and - use the exact same ones - to calibrate the rigExpert.. It is easy to calibrater the Rigexpert... then Repeat your tests...

Great, so much information . but my lack of eyesight and memory would me me struggle with Nano VNA

I decided to go with the Rig Expert and have never looked back.

Nice job !!!!

Hi there, I think when you calibrate the vna and give it the reference plane, to be precise, you should have the calibration standards in format PL259, so you remove them and connect your line. As you did the reference plane is at the end of the sma female of the adapter. Just to be precise. Doing the math abt 400KHz for that quarterwave stub should correspond to roughly 2.6 cm, which could match the length of the adapter you had in line.

My new nano vna Blows the rig expert out of the water. It does things it cannot possibly do!

The Rig Expert is far superior for what we Hams are doing over a NaNo vna, the rig Expert is simple, fast enough, and accurate, Personally, that rig Expert is more than adequate!.🇺🇸✌️😏

I don't know how much it helps but I made some OSL PL calibration standards for my Nano. I wont ever know how accurate they are until I have something to compare the results to :)

Great video as always, was looking at which one to buy so smiled when I saw the video pop up last night. Think the Rig expert is defo more for ouside and field use like you say. The Nano just seems too small and more for when you wre sat down with time and patience, also I can see you loosing those tiny caps for calibration instantly in long grass! Th enano does present great value for money though so could be it. Is the rig expert waterproof?

why not run a two port (S21) phase shift measurement on the VNA for the frequency you are looking for rather than get tangled up in the math? something you can't do on the RE Zoom........73 from Mike, K1FNX near Boston

Cheers Colin

Rookie question. Why do u have to screw anything on to the end of the cable when calibrating an "open" ?

I think you were a little harsh on the nano. Much of the setting up was due to the presence of your patch lead and incompatible connectors. By the same token you have assumed the rig expert was correctly calibrated and you were fortunate the connectors matched. Repeat the test but with the coax terminated in something other than PL259 and you are back to re-calibrating just like the nano. When using the Nano it is important to reduce the scan bounds to be small as possible for best resolution. The smooth curve presented by the nano is done by interpolation between the measured points. Even on a $100k VNA calibration is required for each unique case if you expect accurate results. That fact alone raises questions over the Rig Expert IMOH. So which device gives the most accurate results? Who can say without reference to a higher grade of test equipment. Like the old story says. A man with one clock knows the time. The man with two clocks can never be sure. For quick on-site measurements of antennas and feed lines the RE surly is easier to use but as you say it can not do through measurements of filters or other two port devices. I suggest you beg borrow or steal one of the later generations of the nano, I think you will be pleasantly surprised.

Can you help me out with an issue I’m having cutting phasing stubs. I have no issues tuning cables to a certain required frequency, installing a connector at the far end and making sure the cable including the connector is on frequency. Now, the problem bit! When I change ends and measure again (with and without a short at the far end) I read a frequency that’s sometimes off by 20-60 khz. This happens regardless of whether I am using a Nano or a Rigol DSA815TG spectrum analyser. Do you notice the same, or is this something strange going on at my end?

Really enjoyable video and well presented, thanks Colin. Just something to add, could you use SimSmith or NanoVNA saver to extrapolate the data in a clearer form than on the NanoVNA? I'm with you on the RigExpert choice, I have the 230 and 35, the 35 is my go to as it is so much faster than the 230. The 230 is an older version though, but I do find the difference between my almost brand new 35 and the older 230 amazing. Keep producing these videos, they are very informative. Kev, M0TNX

Who is more accurate?

Great vid. once again Colin. Liked and subscribed. 2E1JBC

Nano The Rig expert is just an overpriced Nano