MR100 Antenna Analyzer Calibration

Calibrating the MR100 SWR analyzer, also known as the Sark100 or Mini60. Please see: / radioprepper DISCLAIMER: The Radio Prepper logo (depicting a microphone) is indeed inspired from a famous flag created in 1775. It is NOTHING BUT a symbol of freedom and independence. It does NOT imply support to any political group. It does NOT imply, represent nor support any ideology with an intent on harming anyone. Freedom means freedom from persecution based on any human trait or belief such as, non exhaustively, race, gender, religion, sexual orientation or nationality. The Radio Prepper channel is a technology and science channel with a focus on preparedness and use of radio technology for disaster relief and small group communications in times of need. It is apolitical and open to anyone sharing the same interests. .
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[@OH8STN]

Always nice to see you posting a new video. Thanks for sharing.

[@sevenoseven8494]

Food for thought and for the hobbiest who has some time on their hands. I connected MR100 to my scope to see what the mr100 was doing during the process of calibration. The MR100 is reading a pure resistive load at multiple frequencies in succession for each resistor value. Typically when we are looking to tune an antenna or see what the reaction is of a device under test, we look at the center frequency of a particular band. What if someone were to, 1) Make an LC circuit that meets the impedance of the resistive load requirements of the calibration test at that 1 frequency. 2) Then calibrate the mr100 to those LC circuits impedance for the one frequency. 3) Then analyze an antenna. 4) Then compare the results to their SWR meter or to another antenna analyzer. Like i said food for thought and for the hobbiest who has some time on their hands! I understand that LC circuits are frequency dependant, and when we use an analyzer we are typically testing the center frequency of 1 band. If this works, it would mean, you would have to make a set of 3 calibration LC circuits for each band and calibrate to a band before testing. Although the above makes sense to me, it is above my scope of practical knowledge.

[@paul.alarner6410]

i would think the calibration would be off as your resistor bodge wont offer a purley resistive load due to the long resistor leads throwing an inductive reactance into the mix,better off using smd components i would think!

[@stephenhughey8460]

I have a Mini60 as well and have also owned the SARK 100 and MR100 variants. They are all a great value for the money but obviously not as capable as a VNA. If you want to make it sing, though, try my software. It makes it even more fun to play with. 73, Steve, AK4R (good on QRZ.COM)

[@RadioPrepper]

Where is your software?

[@stephenhughey8460]

You can find an ad on QRZ.COM ham ad formum searching for SARK 100. On ebay you can take a better look: www.ebay.com/itm/162315019509?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649 or if you get my email off QRZ.COM and email me direct we can make something happen. 73, Steve, AK4R

[@jacknifedbl]

does your software work w windows 10? if so you will make some money off me in 2 weeks!! i am having issues with my software i had on win 7 since i went to windows 10.

[@ralphwilmot6351]

Stephen Hughey yes your software is really useful with the ability to print data and charts. Also avoids the loud beeping noise when using the device.

[@igornowhere168]

"LikE" for remanding about calibration, and "Dislike" because did not show result of calibration - What would be SWR on 50 Ohm resistor? Maybe it would show real quality of this device.

[@RadioPrepper]

+Igor Nowhere Ah, I forgot about that. Precision is not great I think.

[@MrDaim0]

Curious to know if you've studied your antenna used with the Mountain Topper, and the length of 174 Coax used in the Canary Islands!

[@RadioPrepper]

+MrDaim0 The wire length yes, but I should have taken into consideration the coax and used an appropriate counterpoise. I didn't bother because the same setup worked very well before...

[@macdee8628]

Surely the seller should calibrate the unit prior to despatch?

[@RadioPrepper]

+Mr Mc It was fairly accurate out of the box, but of course I had to mess with it... ;-)

[@macdee8628]

Radio Prepper I've just purchased one upon power on it displays uncalibrated :( wanted it to just work thought it would of been calibrated prior to me receiving it looks like I'm off to buy some resistors thanks for your video

[@mpoertner]

This did not turn out so well for me. I had a sneaking suspicion that my analyzer was off a bit so I figured the calibration process would validate that. I measured and made sure my resistors were within 1 ohm of the requested value and now the results are all over the place. I'm not sure if I need better quality resistors or just a better analyzer? Hm....

[@RadioPrepper]

+mpoertner Quality control might not be their forté... I guess you get what you pay for... Still a useful gadget for the price.

[@mpoertner]

Actually, I tried some other resistors and it's back on par with what it was before I messed with it. The new resistors were no more than half an ohm off. I measured with 3 different multi meters to be sure.

[@RadioPrepper]

+mpoertner Might have been the other resistors the wound wire type?

[@danielpincu7743]

Hello! You resistor leads are so long. That isn't interpreted as an inductance by the antenna analyzer?

[@RadioPrepper]

Possibly...

[@atgcbka7707]

hi Gil, what sort of values are you getting back from measuring your standard calibration resistors after calibration? i've just purchased a similar MR100 unit from Amazon. although my 50R was spot on, my 150R was reading only 15 and the 274R was jumping between 1400 and 1500! just wondering if you have similar readings for anything above 50R regards, peter

[@RadioPrepper]

Sorry no idea..

[@atgcbka7707]

@@RadioPrepper no worries, thanks for getting back to me though!

[@electoham]

HELLO WHY DONT YOU USE ALLIGATORS CONNECTORS QUIKLY INTEAD OF SOLDERING .

[@RadioPrepper]

Because I didn't have any.

[@electoham]

@@RadioPrepper JUST KIDDING SIR YOU DID THE BEST YOU COULD DONWORRY .WE DO AWAYS THE WAY WE CAN .GOD BLESS 73 /QRT

[@justcasey3678]

Wouldn't it be easier to just use an alligator clip to the connection points instead of soldering? You have 3 connection points. 50 ohms, 150 ohms, and 274 ohms.

[@RadioPrepper]

Yes, but I didn't have any! A small plastic box with a three way switch would be even better...

[@ralphmills7322]

I use these BNC to screw terminal connectors for my Chinese Pixie II Xcvr Kit as a dummy load with the kit supplied 51 ohm 1w resistor. works great! Buying 3 or more is discounted. Provides quick changes for your three calibration resistors. www.banggood.com/Wholesale-Coax-CAT5-To-Camera-CCTV-BNC-Video-Balun-Connector-p-29842.html?rmmds=search

[@molly1958]

Mine worked ok when it needed to be calibrate . But I try to calibrate it and missed it up. is there any way it can be set back to factory default?

[@RadioPrepper]

Same for mine. Unfortunately I don't know.

[@stewartrv]

Hi Gil I was just wondering if you ever check this against other known good analysers and if so what was the result? Also I read on some of the other variants purchased from eBay/AliExpress etc they were fitted with AD9850 (or a fake) instead of an AD9851 hence they don't work very accurately. I've just got an MR300 which is also a SARK-100 clone but in a metal case and mine came with a chip marked as AD9851. In any case I will take it to my club and see how it compares to other branded ones. :)

[@RadioPrepper]

I tried it against my KX2 SWR meter. It showed a higher reading. Indeed not super accurate..

[@stewartrv]

According to some reports if its 1.5 x the frequency it has wrong chip... Prob worth checking the chip#. I still haven't been able to test mine yet...

[@RadioPrepper]

Mine sure isn't 1.5x the frequency.

[@TI2GBB]

Hi! Thanks to sharing this, I have one of this in my house... could you please share the resistances that you have used?

[@TI2GBB]

Second question: I saw that you just remove the weld and apply again a resistance, could you please explain me more? I have one of this but I need to calibrate since I bought. Thanks and regards from Costa Rica.

[@RadioPrepper]

Hi, this will explain it: I make a 50ohm resistor by putting two 100ohm resistors in parallel. To get 150ohm I add a 100ohm resistor to that bundle, in series. The 274ohm resistor comes in that value. I had to solder the resistors quickly because the calibration process does not wait for you...

[@jkbish1]

why not use alligator clips?

[@RadioPrepper]

Better conductivity soldering.

[@jeromegrzelak8236]

One connector with 3 switches to cal mn

[@RadioPrepper]

I will do that, definitely.

[@nickjaxe]

Is this process necessary for this unit to work accurately?

[@RadioPrepper]

No, it comes calibrated from the factory.

[@nickjaxe]

Thank you...is it a kit or pre assembled.

[@RadioPrepper]

Pre-assembled.

[@ralphwilmot6351]

I us 3 resistors with crocodile clips to switch between them, quick and easy. Also found the calibration is necessary from time to time to keep it accurate.

[@buckcherry4775]

@@RadioPrepper NO they dont, I just bought 6 for resale

[@johncundiss9098]

Hmmmm. You don't have one single Bayonet Navy Connector 50 ohm terminator? Understand the others but no 50? Working on building an analyzer myself I want my quality control in it though, and not cloned/stolen by china parts, or rubbed off part numbers. 73's

[@RadioPrepper]

No, I don't have a scope, so never needed one... I do want to get a better analyser for sure..

[@johncundiss9098]

Hey there. thanks for the shout out. Ugh. Long story here, took up electronics again keep my mind busy since disability, yea mental and physical problems, those aside, lol..... Done a lot in electronics, how they work, how they built and such, nephew bought me 2 used ham sets, very old, a Kenwood ts-580s and a Yaesu ft221r. That opened up another can of worms, a good can though, made some new friends and have filled in a lot of gaps in the frequency domain of the electronics spectrum. I try to sum up a bit. Brand name VNA's or a spectrum analyzer is pretty expensive. Been seeking myself. Got 2 scopes here, I invested in an MSO4000 from Rigol. Am saving for a spectrum. Understand about money, hobbies, compromise. I looking at same analyzer but am skeptical just like am skeptical about the ad9850, 9851 dds bourds themselves. Actual Analog devices chip in one off quantities is 14 bucks, Digikey. These things gotta be fake in some ways. I have been trying to get better high res. pics of said analyzer to inspect myself. There are ways to tell. If willing to take apart and look.... Ugh. I am babbling. Sorry. Look up the datasheets for the ad98505/51. It shows you how to make a dds signal generator that they are using. See if you can match the filters up in the schematic they have with the analyzer, any stages missing? Look at the chip closely, if it is fake it will have bad printing on it and such. In any case, nice to meet another ham, similar interests. I gonna try watch few more your video's. Ya kinda new to me. 73's and sorry I rant.

[@RadioPrepper]

Yep, I'd love a RigExpert AA-600 but it's about $700... That said, it would probably be more useful to me than a scope. I do have to troubleshoot kits sometimes but usually spend more time building antennas...

[@johncundiss9098]

Yea, that's next for me. Thing is I think I could build some antenna's but unable to put them out in the field for testing. Maybe in future we do a hookup and I send an antenna or 2 for an outside opinion of it. Very good chat here. 73's. And I am watching. P.S. I look into this rgexpert model, there is another called miniVNA I believe and is a bit cheaper. But also unsure of how it performs. Good luck and long fun on the HAM bands.... JC, peace.

[@RadioPrepper]

Thanks John, sure, I'd be glad to test anything you send my way..

[@picwiz2]

Uhmmm, that is not a calibration procedure: you do not use a non inductive components: also do not forget that every conductor is an inductor and every couple of conductors is a capacitor! Avoiding wire resistors is not enought! Add the transformations operated by the coax stub plus bnc connector you used ... After a calibration like that, you obtain false values and incorrect results. If you don't believe me, after your calibration, try using a dummy load connected STRAIGHT to the instrument connector and try also using a 25 Ohm and a 100 Ohm in the same manner. Now, my suggestion is to use just a bnc to SO-239 adapter included in the calibration (if your antennas to test have a cable with a PL-259 connector) and prepare a PL-259 for each calibration step using smd resistors (the smallest ones you can manage) and, if possible, more than one resistor in parallel in order to reduce the inductance. Of course, you have to solder the resistors INSIDE the connectors. Have good antenna testing. 73s.

[@RadioPrepper]

Good idea thanks!

[@sevenoseven8494]

Food for thought and for the hobbiest who has some time on their hands. I connected MR100 to my scope to see what the mr100 was doing during the process of calibration. The MR100 is reading a pure resistive load at multiple frequencies in succession for each resistor value. Typically when we are looking to tune an antenna or see what the reaction is of a device under test, we look at the center frequency of a particular band. What if someone were to, 1) Make an LC circuit that meets the impedance of the resistive load requirements of the calibration test at that 1 frequency. 2) Then calibrate the mr100 to those LC circuits impedance for the one frequency. 3) Then analyze an antenna. 4) Then compare the results to their SWR meter or to another antenna analyzer. Like i said food for thought and for the hobbiest who has some time on their hands! I understand that LC circuits are frequency dependant, and when we use an analyzer we are typically testing the center frequency of 1 band. If this works, it would mean, you would have to make a set of 3 calibration LC circuits for each band and calibrate to a band before testing. Although the above makes sense to me, it is above my scope of practical knowledge.