jueves, 18 de abril de 2013

SARK100 Clones at eBay

Recently I found several SARK-100 clones sold at eBay. The "Mini" units look a nice improvement to the initial hardware design.

Notice that I do not have any link with the manufacturers and sellers and I cannot ensure the performances and provide support for these units.






25 comentarios:

  1. Hi! I just got the MA60-X1 delivered from China, and it seems to be a very neat and useful little instrument. However, the unit was delivered without any manual or any instructions whatsoever. Do you have a hint about where to find that?

    73's de Hans / LA2MOA
    KQ50ni - EU141

    1. Hi Hans,

      You should ask your vendor since I only provide support to the customers of the original SARK-100 Kit.

      I do not have any relationship with any of these SARK-100 clone vendors and any control in the product and in what is delivered with the product.

      Anyway, the original SARK-100 kit information is available at: http://www.ea4frb.eu/antenna-analyzers/sark100

      73’s de Melchor – EA4FRB

  2. Are somebody use this analyzer? I'm already loocking for analyzer. But bit I dont know are chinese delivering fully working units? Or just nice useless boxes? Thank you.

  3. I got the feedback from two buyers of one of the models (the bigger unit, not the MA60-X1) reporting both two problems with the device:

    - USB not working due to faulty FT232 chip
    - Output frequency 1.5 times lower than selected

    The source of the second problem has not been identified yet but it looks that it is due to a faulty AD9851 chip.

    I do not know if this is a particular problem to these units or a broader problem so just to make you aware.

    73's de Melchor - EA4FRB

  4. Same problem here with output frequency 1.5 times lower.


  5. Hi Steve,

    I am sorry that you have faced the same problem with the DDS.

    I know from one user that he solved it by replacing the DDS chip.

    I wonder if the vendor has provided you any kind of support for solving this issue.



  6. I did not contact the vendor and it would probably cost me more to return the unit than to replace the DDS chip. I'm happy with what I got for the price, fixing it should not be a big deal. It's still a sound design with open documentation, once I purchase a new DDS chip from a proper vendor(here it would be Digikey or Mouser), I'm sure that it should work fine.


    Steve VA2PSL

  7. Hi! Have the same problem with the SARK100 clones - a 1.5 output frequency multiplying and a faulty FT232. All the clones are from different vendors. In my point of view, the issue is a wrong firmware or the wrong MCU fuses, because the PCB is practically identical. What do you think, is it possible? It seems more that AD9851 has a wrong software controlling , than it is faulty...



    1. Hi Kirill,

      Unfortunately I do not have an unit in order to perform a correct diagnostic. I know from one customer that this was solved by just replacing the AD9851 and the FT232 chips.

      This is in any case very strange this broad fault of the AD9851 chip so I would not definitely conclude that this is the cause or could be related to a wrong programming of the MCU.

      Anyhow what it is evident that the testing of the output frequency is not in the manufacturer test plan and all of this could have been prevented with a right validation at manufacturing.

      73's de Melchor - EA4FRB

  8. Thank you, Melchor! Replacement of the AD9851 solved the problem!


  9. Just to confirm that I did replace the AD9851 on my unit with success.

    Steve VA2PSL

  10. I purchased one of these sark100 analysers from ebay, imported from china and sure enough it outputs a frequency

    was 2/3' s lower than indicated. ie for 21mhz it measured 14mhz.

    Rather than sending the item back to china and asking for my money back I decided to investigate the data sheets

    for the ad9851 dds chip and I found that there is supposed to be a x6 reference frequency multiplier inside,

    30mhz x 6 = 180 mhz.
    Thinking that this was not operating correctly and may be only multiplying by 4 times. I looked at the source

    code part for the dds (dds.c) to try to figure out how it calculates output frequency.

    At the beginning of the code there are a couple of lines as follows.

    //#define REF_FREQUENCY (4294967296/180000000) //30Mhz ref clock times 6
    #define REF_FREQUENCY_NUM (42949673) //30Mhz ref clock times 6
    #define REF_FREQUENCY_DEN (1800000) //30Mhz ref clock times 6

    I changed the line #define REF_FREQUENCY_DEN (1800000) to

    #define REF_FREQUENCY_DEN (1200000) //30Mhz ref clock times 4

    and after reloading the altered programand the device now outputs correct frequency.
    (I had to build a PSOC programmer first which took me three weeks to get working properly)

    I know very little about .c programming and very little about maths and do not know if this mod is correct. but

    would welcome comments. Mike G8KYT .

  11. Hi Mike,

    This workaround should work for compensating the frequency due to the faulty DDS chip.

    The issue is that because the lower master clock frequency, the maximum practical output frequency will be 40MHz instead 60MHz. This will not mean that will not work ap to 60MHz but because the low quality of the output sinewave, it will be reduced the accuracy of the measurements.

    Melchor EA4FRB

  12. hello
    I bought a Chinese unit and found that the device does show on the computer and you can communicate with it. though I wiped the chip when trying to program it. I reprogrammed the chip through the psoc, I had to solder on connector pins. I got the chip reprogrammed and it worked ok. I cant test it though, or don't know how to test it. I have tried it on a second hand multiband whip that sits on my car. i have had a lot of problems trying to get this antenna working without the analyser. so i don't know if the antenna is faulty or not. i set the antenna to the "correct" length and put the analyser on it. it shows resonance on 13.mhz. not exactly but moves around. i then try to scan and nothing matches. what is the best way to test the unit?
    is there a good way to reprogramme without losing any of the units functionality.

  13. hello
    i have just tried to correct the frequency problem and now i cant get past the "not calibrated, press a key" title. it jams up. anyon got any ideas please

  14. I have a problem when opening psoc with the sark software. it says not all files located, confirm path(or something like this) I find that the measure.txt is deleted. I have downloaded this software a few times and this still happens. im not sure what the problem is. any help
    after building the program, it says 0 errors and 32 warnings. is this normal?

  15. I just got one of the Mini 60 versions, it also read Hz 2/3 too low and had no USB connectivity. I replaced the AD9851 and the FT232 chips with real ones, after carefully inspecting soldering, checking voltages and and ohming out the original chips and its traces (that was not the problem!)

    The new genuine chips do not look exactly like the originals, there are small printing and other differences. I believe the originals to be counterfeits. Replacing the two chips resolved both the frequency and USB problems -so far, still testing. All testing done with a 0.0 to 2.4Ghz Freq counter, and DS1102E DSO. It's on freq now in all bands at 2.48v p-p. I also used a SDR receiver to check the output frequency from the analyzer as a quick double check. Same could be done with a digital readout receiver..

    From what I read on the web, at eham, etc the Mini 60 version seemed to be less prone to these problems, but not in my case. My Mini 60 has an orange, not red, board. It did say MA60 X1 but did not have the silk screened URL. The traces are very fragile, so take care if you replace chips -use Chip-Quik or a desoldering station. There seem to be a few circuit differences from the schematic here, mainly filtering related as far as I can tell. Also, there is a trim pot near the PSoC -I assume that's to trim the voltage, or the bridge, or tweak the frequency?

    I do like that the Mini 60 has a metal case and is so compact. Works well enough once you replace the USB and DDS chips. Did some scans and I loaded them into Zplot, that worked well. Poor man's VNA. I have not yet attempted to update firmware, etc. Have not hooked a ISP to this thing either. The device reports in hyperteminal it already has the latest firmware, but who knows.

    Bottom line; Even with these problems, it is a deal. But be prepared to replace the AD9851 and FT232 chips -and recalibrate. I would advise doing that before I would consider modifying the programming. Not that hard, its just an annoying PIA.

  16. ninjaman1138

    You can test if the frequency is correct just by coupling it to a digital readout receiver, or a scope, frequency counter, etc. Frequency on the Sark LCD should match frequency on the receiver. As for other tests, those are described in the manual you can download, it describes the calibration procedure and also has info on building some 'dummy" test antennas.

    The Sark100's are not that different from any other antenna analyzer, and the AntlantaRadioClub has a series of videos on their You Tube channel showing how to use one.

  17. OK, on the Mini 60 (Max 60 X1) -the little potentiometer next to the PSoC is for adjusting the display contrast. Also, the battery is a 4.2v Li-Po -which means this thing must have power supply with a switchmode boost circuit -different than the original Sark100.

    Be advised that if you intend to use PSoC Designer, if you don't have experience with that product (like me) -use PSoC Designer 5.0 SP6, ( linked to in the Sark100 users manual) -not the new 5.4 version! Otherwise if you try to load the Sark100 project workspace you will get a lot of confusing nags asking you to update things in the project, and you will get a missing "message.txt" and other error messages if you try to make a new hex file.

  18. great to see some conversation about there devices.

    I had my own share of issues. Mine was screen issues and I think the display driver chip is at fault. There is voltage to the display. Initially I thought they display was at fault so I got a new display to match and replaced and there is still a fault.

    The buttons on the device all used to work but I tried flashing the unit and it now appears to be bricked. I cant see anything on the screen to confirm or deny this but now the buttons do not give a audio confirmation.

    Im going to get a replacement display chip and go from there and will report back.

    Denis M0USV

    1. Hi Denis,

      I have same issue like you. On LCD screen problem. So now how you solve the LCD screen problem ? I don't think is LCD panel problem. May be is microcontroller problem ?


  19. I have a Sark 100 china clone, purchased about a month ago. Took about 10 days to come and works perfectly. (I have not tried usb but frequency is dead on) I am very pleased to say the least and i am now experimenting with all sorts of wire antenna. I would say it is one (if not) the best shack accessory I've ever purchased. Only gripe i have is no battery holder when shipped so you have to get 2 x (4 aaa) holder and install. at the moment i am using a 3 cell lipo battery with a lead to the external power plug. All FB.

    Toby MM0TOB

  20. Hi all
    I recently bought Sark100 antenna analyzer from China because it was cheaper.
    I did the calibration according to the user manual of EA4FRB and finally after 274 ohm resistor removed Donne appears and you have to press the button VAL procedure not finish.On display appears again "in Progress" and then ask again 3 resistant. if placed on row 3 resistors 50, 150 and 274 ohms measured SWR is the same.If this has happened to someone so! ...... Please Help ......Waiting for suggestions for solving these problems from anyone.
    Marinica yo3fqa

  21. I try to power on the unit suddenly the LCD screen display all the words lost and not working well. The back light of the LCD screen looks like lost power (back light lcd screen dimmer) when all the words is lost. I've tried contact my seller but no reply. In this case, what I can do with it to solve the problem ? Thank you.

  22. Buen Día !!! alguien me puede informar como arreglar el error que se ve en este video ????? LU3DJ Daniel , 73"" https://drive.google.com/file/d/1-w-jkHMgyQx2-WlWwClGbSIVllhfMVR5Lw/view?usp=sharing