VNA or Antenna analyzer - Page 1
Forum section: electronics / rf-microwave

author: hneve
author_rank: Regular Contributor
timestamp: May 31, 2016, 07:25:43 am
content: Hi there,I have now taken the step I've been thinking of for the last 20 years, I contacted the local Ham club and asked to take the license test, they responded that they didn't have any courses set up, but that I could get some helt for self studying. long story short; I asked to just take the test as it free to take the test, you only pay for passing. And I passedI have built a few antennas and I'm atm relying on my length measurements making the antennas usable, I have talked about analyzers but as RF still is somewhat of a unfamiliar field for me I lack answers in regards to equipment. So I have looked at rigexpert aa-600 , but I'm also intrigued by the miniVNA tiny. The tiny is a bit cheaper than the AA600 and has a wider range. If someone could enlighten me as to pro/cons of these two , and maybe share some experience.The reason I want one of theese is that i would like to test antennas in the UHF segment. So if you have a different approach I'm up for suggestions.

author: borjam
author_rank: Unknown
timestamp: May 31, 2016, 07:38:22 am
content: I can't tell you about the RigExpert ones, but I own a MiniVNA tiny and I love it.It has its drawbacks of course, but it's still surprisingly competent as a VNA. I used it to measure some UMTS and LTE antennas and, compared to an Agilent E5061B, it held its own quite well. Of course it's not the same thing, but it's not a toy either.Looking at the RigExpert, both are VNAs. RigExpert doesn´t give a dynamic range figure for their analyzers, although I guess it will be in the same order of mafgnitude as the MiniVNA.I think the main difference between them is the intended usage. The MiniVNA tiny is a rather complete VNA offering S11 and S21 measurements (which means, you can measure filter bandpass with it) and the RigExpert are more specialized antenna analyzers. The RigExpert is much more convenient to use in the field or on a roof, and it is more flexible regarding measurement impedance. The MiniVNA Tiny is fixed on 50 ohms.So: to summarize. Considering lab usage beyond adjusting antennas? MiniVNA Tiny. Need something flexible to carry to the field, maybe to a rooftop, and you don't need S21 measurements? RigExpert.Cheers,EA2EKH

author: hneve
author_rank: Regular Contributor
timestamp: May 31, 2016, 08:07:10 am
content: So I'm correct in thinking that these two do the same job, only the AA600 is more convenient carrying around on a rooftop.And the Tiny has a few more functions in regards to "lab" work.I found this " Impedance (Z) can be measured from 1 to 1000 ?, the dynamic range is up to 70 dB. ", you say the tiny is locked to 50Ohm impedanse could you elaborate as I cant find anything about this?.

author: borjam
author_rank: Unknown
timestamp: May 31, 2016, 08:18:29 am
content: Quote from: hneve on May 31, 2016, 08:07:10 amYes, sorry.As far as I know, the MiniVNA Tiny can give you a S11 measurement (that is, return loss/SWR) only from the point of view of a 50 ohm antenna. That is, you have an antenna that you are intending to connect to a 50 ohm rig. You can use the MiniVNA Tiny to see how the rig will see it.But what happens if you intend to connect an antenna with an intended impedance different than 50 ohm?Imagine this example. You are building an antenna which, by design, is not a 50 ohm antenna. For example, it's a 100 ohm antenna. Being a 100 ohm antenna you will use some matching network/coupler to connect it to your rig. But you need to check the matching between the antenna and the matching network.The RigExpert can do it, it would be less convenient with the Tiny as far as I know.

author: Electro Fan
author_rank: Super Contributor
timestamp: June 02, 2016, 04:42:11 am
content: Another analyzer for consideration:http://www.sark110.com/Not as rugged as the RigExpert 600, doesn't do UHF, but does a LOT (you can easily select the impedance you prefer and a bunch more), and it costs less.

author: TheSteve
author_rank: Unknown
timestamp: June 02, 2016, 05:52:48 am
content: The RigExpert AA-600 can be used to 1.3 GHz with great results and to 2.4 GHz if you use a computer and the USB interface with it. It also generates mini smith charts.

author: hendorog
author_rank: Super Contributor
timestamp: June 02, 2016, 06:20:30 am
content: Quote from: hneve on May 31, 2016, 08:07:10 amJust reading that I am not sure if you picked up on the other point borjam made -The Tiny can measure reflection and transmission. The Rigexpert, and the other antenna testers, can only measure reflection.Reflection measures S11 which is what you use to measure an antenna.Transmission measures S21 which is what you use to measure a filter or a cable.

author: Electro Fan
author_rank: Super Contributor
timestamp: June 02, 2016, 06:36:49 am
content: SARK-110 has built in reflectometer (TDR), a database of various cable characteristics, and a band scan (spectrum analyzer) function.

author: ldillon
author_rank: Newbie
timestamp: June 02, 2016, 03:17:47 pm
content: I've got the AA-600 and I really like it. I suspect that it will last a lifetime and it's much nicer than the MFJ black box SWR meters. If you want a dedicated antenna analyzer, it's hard to beat, if a bit expensive.