RigExpert or NanoVNA - Checking 1/4 Wave Coax Stubs

[@yamakawa511]

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

[@MM0OPXFieldRadio]

Yes, the more you use it the better value it is.

[@SurvivingTheApocalypse]

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

[@MM0OPXFieldRadio]

Yes a great tool for life.

[@phils2180]

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.

[@MM0OPXFieldRadio]

The NanoVNA is great when you have time and inside. Can't beat the Rigexpert for field use.

[@George-W-Jenson]

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

[@trig6712]

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

[@MM0OPXFieldRadio]

I even struggle. Its something you need to keep using or you forget.

[@itsonlyme9938]

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.

[@MM0OPXFieldRadio]

Thats right. I should try it but 99% I'm using this in the field.

[@itsonlyme9938]

@@MM0OPXFieldRadio Yes OK . I have built a wide band transformer which was nearly flat from 1.8 mhz up 25 mhz then it started dropping of at the HF end shown using the RigExpert ANT2 software and I can set the sweep range for a given band. Connecting it to your computer will power up The RigExpert G4LMZ

[@iamhe999]

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...

[@bryantwalley]

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.

[@RobB_VK6ES]

Agree entirely. lack of sample points is one of the nano's shortcomings. During calibration the nano distributes it's sample points to fit the span you selected for stimulus

[@IZ0MTW]

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.

[@MM0OPXFieldRadio]

Yes I need to get PL259 reference standards.

[@jamesgoodrich8355]

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

[@MM0OPXFieldRadio]

No such thing as a rookie question. Being pedantic, yes there is an "open" connector but at HF its likely notbto matter.

[@iamhe999]

Because.

[@markatherton7213]

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

[@MM0OPXFieldRadio]

For any single port measurements totally agree.

[@ronballad7611]

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 :)

[@MM0OPXFieldRadio]

Let me know if you do do a comparison.

[@Mrjokerman]

Nice job !!!!

[@MM0OPXFieldRadio]

Thanks 👍

[@121richard12115]

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?

[@MM0OPXFieldRadio]

You have nailed it. The rig expert comes with a cover too which will provide rain protection. I wouldn't say it's waterproof but I wouldn't be worried if a rain shower appeared. The NanoVNA has no chance on in the rain as is.

[@121richard12115]

@@MM0OPXFieldRadio British weather it has to have some kind of water protection so thats good. Think everyone in the UK has been there, stood in a field or garden hours before a contest is due to start and still trying to work out why somethiing isn't right :) Think the MFJ 259 used to be the common tool but seen the rig experts used everywhere now. Definatley on another level. Are you going to be at GMDX?

[@MM0OPXFieldRadio]

@@121richard12115 seen it advertised the other day. Probably not but an outside chance I may be able to attend.

[@davidhamilton4950]

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

[@MM0OPXFieldRadio]

Yes, it has an S21 port. For S11 measurements only I take the Rigexpert.

[@davidhamilton4950]

@MM0OPXFieldRadio Plus you cannot use the rig expert for VHF or UHF. Not unless you want to spend $500.

[@MM0OPXFieldRadio]

Agreed. See when your outside in winter and it's freezing, I know what ainwoupd rather be using. Nothing against the NanoVNA, I love mine too. They are just not built for fast field work. Ive dropped my Rigexpert where the NanoVNA would get destroyed. Just as well as they are inexpensive.

[@davidhamilton4950]

@MM0OPXFieldRadio I do not plan on being the freezing cold myself that often. I primarily use mine in the comfort of my shack

[@brendanhynes473]

Cheers Colin

[@rballad142]

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?

[@MM0OPXFieldRadio]

What do you mean by changing ends? Do you mean connecting the other end of the coax?

[@rballad142]

Yes, have you ever done that test and made sure the frequency at both ends is the same? I read as many as 40-60 khz lower on all my cables. It’s driving me insane trying to figure out why!

[@rballad142]

I hope i haven’t confused you. What I mean is leave one end open and tune. Once the Z or the reactance is lowest on the wanted frequency, put on the connector at the far end. Measure to make sure the frequency is correct. Now, I disconnect the cable and connect the other end where I just installed the connector and measure again to make sure I have the correct frequency to make it 84 or 71 degrees. The problem is that the cables never read the same at both ends! If one end is 15.200 the other end might read 15.035.

[@michaelpolimer2128]

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

[@MM0OPXFieldRadio]

I will look to try that. Thanks 👍

[@UDX4570PalmSprings-yh1mv]

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!.🇺🇸✌️😏

[@MM0OPXFieldRadio]

I will always grab by Rigexpert first for an apples for apples scenario. Unfortunately there is many functions the Rigexpert cannot do as it has no S21 port for through measurments.

[@UDX4570PalmSprings-yh1mv]

@@MM0OPXFieldRadio I'll gladly give up the 2nd test port to maintain simplicity any day! Merry Christmas to you and your family✌️🎅👍

[@MM0OPXFieldRadio]

Thank you have a great Christmas and New year

[@George-W-Jenson]

yes

[@TingILi]

Who is more accurate?

[@MM0OPXFieldRadio]

Who knows. I would need to lab calibrate both to see the error.

[@RobB_VK6ES]

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.

[@MM0OPXFieldRadio]

I've grown to love my NanoVNA, I use it for things the Rigexpert cannot do. I would love to get a bigger screen new version. Its incredible what it can do for thr cost. I want a TinySA too.

[@RobB_VK6ES]

@@MM0OPXFieldRadio I have the Tiny SA Ultra as well. It's operation is even more complicated beyond simply looking for harmonics and my gut feeling is it is intrinsically less accurate since it's minimum resolution band width is so large along with a slow scan rate and it lacks a tracking generator. While popular it has failed to garner a user base like the Nano

[@davidhamilton4950]

My new Nano DNA blows the rig expert out of the water. It does things it cannot possibly do

[@kevhaworth5313]

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

[@MM0OPXFieldRadio]

Appreciate your comments Kev. I will do that. After this comparison I discovered one of those connectors is dodgy. If I connect each end I get a way different resonance frequency on either unit. I have another 20m delay line made from RG213. I'm going to compare that one to this one.

[@johnbuckley683]

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

[@MM0OPXFieldRadio]

Thanks John 👍

[@robertbobbitt8448]

Nano The Rig expert is just an overpriced Nano

[@MM0OPXFieldRadio]

Chalk and cheese. You couldnt take a NanoVNA in the the field and expect it to stand up to the rough handling.