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Thread: Low cost VNA - thoughts?

  1. #26
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    So...finding accurate pictures of these things is even harder than finding a quality supplier. Any chance you could send to me or post a couple pictures of yours?

    I'm working on contacting them and being able to provide proof of yours may help my case since you also bought from them. Thanks for the heads up on the different switch. I didn't even know it existed! So much for standards.

    On the flip side, I experimented with it a little bit last night and the capabilities you get for $50 are impressive. I'm slowly starting to build my inventory of personal test equipment and this is a nice little tool to add to it. I even found linux friendly software, with TDR, to use with it.


  2. #27
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    Yes, NanoVNASaver is probably the best SW out there for the Nanos. The Chinese NanoVNA or NanoVNASharp software is more limited.


    OK, here's some pics of my unit, the first thing I noticed was my PCB was blue, yours is green, plus all the other stuff I listed are things to look out for, or differences at any rate. Mine is considered the "best" of the 3 construction/manufacture grades of unit out there.

    20191023_002432.jpg

    Also, I installed a "D2" diode to get a functional battery meter/indicator. The later firmware(s) support this but if you have no D2 installed you just get a blank red battery symbol. Note my D2 is a little ugly, all I had handy was a dual-diode in an SOT-23 package, so I'm just using one half of it. A prettier solution would be a proper SOD-23 axial 2-lead type diode package, 1N914 or 1N4148 equivalent. Cathode to bottom (K), Anode to top (A).

    20191023_002507.jpg

    Finally, here's two shots of the outer "cover" PCB, I noticed a QR code on the inside and the outside markings are shown FYI:

    20191023_004119.jpg20191023_004206.jpg

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    Thanks, Alpha.

    I received a reply back from them (grammar and spelling left intact):

    We are sorry to hear that you are not satisfied with our products of quality .We usually get the items from reliable suppliers and we regret that we have not met your requirements. Could you please attach pictures for us? If it is not convenient, you can provide more details about the products so that we can provide a better help for you as soon. Thanks for your help.
    Yours sincerely,
    Sunshine houseee
    I replied with pictures and reiterated the differences.

    While searching for more details about any recommended legit suppliers, I found Gigaparts is also selling these. Of course they claim the one they are selling is the "best" and has been validated. The pictures show characteristics of the better versions, but even theirs doesn't match yours.

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    New firmware is out (it's updated quite frequently). Here are the recent changelog notes, converted from Chinese to English. Some of this may be a little hard to understand...

    https://drive.google.com/drive/folde...MEsPpIvRVTG7hq

    Oct 18, 2019
    1. Synchronize the latest version of edy555, but do not disable function inlining, so the flash space is not enough, the Version interface shows less point content, TDR mode shows that two Mark points function is not synchronized to save flash, which may use the last one of inline optimization Version, the screen speed will be significantly slower after the function inline is disabled;
    2. Fixed the problem that the AA version clear_flash is not properly emptied;
    3. After recompiling, you can connect to the cho45 web interface normally, but I don't know where the problem is. It may be the previous version of the flash limit, and there is a problem with the compilation.


    Oct 9, 2019
    1. Synchronize the edy555 code
    2.AA version display details optimization

    Oct 8, 2019
    1. Synchronize the latest code of edy555, because you can use the command to set the harmonic switching point, no longer compile the 800MHz version;
    2. Since the harmonic switching point is variable, the modification si5351 is consistent with edy555.
    3. The AA version reduces a set of calibration data save space, and the extra 6K Flash is used to store large fonts.

    If you need to modify the harmonic switching point, use the threshold command.
    example:
    Threshold 270000000
    Saveconfig

    Oct 3, 2019
    Combine the ANTENNA_ANALYZER (AA) version.

    --

    Latest NanoVNA Saver (software):

    https://github.com/mihtjel/nanovna-saver/releases

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    Here's a pic of mine:

    20191024_051921.jpg

    Here's where I purchased from:

    https://www.ebay.ca/itm/NanoVNA-HF-V...72.m2749.l2649

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    You guys have to check this out... A rubber case for the NanoVNA. Multiple colors available, quantity discounts. Link courtesy of com501.

    https://www.ebay.com/itm/NanoVNA-Case/174039026524

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  12. #32
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    Mars, your board looks almost like mine, but yours has the older style jog switch. Otherwise, yours has the better shielding and slightly larger battery like the one I have.

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    Quote Originally Posted by Alpha View Post
    Mars, your board looks almost like mine, but yours has the older style jog switch. Otherwise, yours has the better shielding and slightly larger battery like the one I have.
    I hate the mechanical operation/feel of the switch. If you have a suggestion for a better part/source, I'm all ears. That thing needs to go. It feels horrible/cheap..

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    I believe those switches can be had on the open market. I seem to remember coming across some post somewhere that pointed to the newer replacement part for it. I'm sure you could easily replace it with your soldering skills, the only challenge would be to try and find the part. I'll go through my files and links to see if I can find the reference.

    I have also seen some hacks that involved using the side-flex from an old Jedi or somesuch radio, and tacking the flex to the right of the display giving large up, down and select buttons that way, instead of them being PTT, SB1, SB2 or whatever their old function was.

    P.S. You need to add a "D2" to yours if you haven't already. I stole a SOT-23 dual-diode from an old GP300 to do mine.

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    Quote Originally Posted by Alpha View Post
    I believe those switches can be had on the open market. I seem to remember coming across some post somewhere that pointed to the newer replacement part for it. I'm sure you could easily replace it with your soldering skills, the only challenge would be to try and find the part. I'll go through my files and links to see if I can find the reference.
    Replacement is trivial. I just don't know what to call it or what to search for. It's like trying to search for the rounded slotted nut I need for the 7550 SMA mod. Everyone wants to call it something special. Trying to find it has been made difficult because stupid fucks can't decide on a common description for it. Same deal with this "pushbutton rocker switch selection multi-slider" or whatever the flying foxtrot.

    Some day, we'll have tech/apps on the phone which scan the part and make a 3-dimensional model of it, then search based on that. It's coming.

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    Some synonyms for it seem to be Jog Switch, Jog Wheel or some combination of the two.

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    I heard back from the supplier again. It took a little back and forth, but they have agreed to refund the full amount of my purchase.

    In addition I will be keeping the device. They actually suggested that based on "Considering the high freight and in order to save time and money for you". I don't think they really understood if it was going back I wasn't paying for it, but it never got that far.

    Through my conversations with them it seems very much that they are just a middle man and are not actually manufacturing them. Given the different name they signed their messages with I'm guessing maybe even a couple times over. Multiple times they referenced their "reliable suppliers". They also claim that they will "strengthen supervision of quality in the future", but I have my doubts.

    They initially offered a partial refund, but I insisted on a full refund and they went with it.

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    Box, consider ordering from the link I posted. You will get that welfare rocker switch, but at least you know you have some shielding and the larger battery. I used mine last night to do up a duplexer. Aside from a slow refresh rate, it did a really good job.

    signal-2019-10-25-062524.jpgsignal-2019-10-25-062524-1.jpg

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    Actually I looked closely, and the rocker switch looks almost exactly identical to mine save the mushroom-shaped actuator. At the hazard of a very "permanent" mod, I might suggest snipping or cutting off the wheel-shaped extensions of what looks like the mushroom beneath all that nonsense.

    Comparing the two, it looks like they just trimmed it down, and perhaps made it a tiny bit thinner overall but that shouldn't matter. When you lose those "wheel" shaped extensions the benefit is you can push the actuator from side to side by putting your finger on the corner of the mushroom. That makes it much more positive and less flimsy feeling since you are getting more leverage by getting at the "underside of the mushroom cap".

    Closely compare the pictures of the two, other than the wheel they look identical, and you can see the mushroom-shaped outline in the structure of the wheel's frame. You'll see what I mean.

    Also, box, thanks for sharing your experience. I'm glad they refunded your money, plus you got one for free to boot! Add shielding, mod your switch, add D2, and you should be good to go! (whew!). I will not be recommending those guys anymore since they seem to be middle-middle-middle men. Sorry you had to go through all that nonsense!

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    I have not had time to do a write up on basic usage of the little box, but have been using it side by with our LMR Master and have found that aside from a tenth of a db difference in measurements, the thing is spot on. Absolutely wonderful for quick go / no-go decisions on antennas and feedline.

    Mars, I also used it to tune up a UHF duplexer this week, then verified with the LMR master and R8000. Aside from the slow refresh, it is spot on.

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