[time-nuts] Ebay Huawei Ublox M8T Modules Warning

[Bryan _]

Not the previous links as but this/these ones

https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs

User on EEVBLOG mentions , true or not I don't know, but they did not have any luck.

https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/new/?topicseen#new

Starting at reply/post 890


-=Bryan=-

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob kb8tq <kb8tq at n1k.org>
Sent: February 20, 2021 1:53 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi

What leads you to believe that these:

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Are fakes?

Bob

> On Feb 20, 2021, at 3:40 PM, Bryan _ <bpl521 at outlook.com> wrote:
>
> Apparently listing are fake Neo's, but perhaps unsoldering the pcb board may be worth the money for a module swap. Although the not sure if the M8T is pin compatible with the 7M modules. Don't see any documentation either, but I am sure there is other similar boards out there on fleabay.
>
> https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs
>
>
> -=Bryan=-
>
> ________________________________
> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob kb8tq <kb8tq at n1k.org>
> Sent: February 4, 2021 7:01 PM
> To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
> Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning
>
> Hi
>
> Again, in case anybody else is interested ….
>
> https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
>
> Turns out to be a bit more than what the listing implies. The parts I got
> also came with a cable that goes from the round connector on the assembly
> to an HDMI connector. That explains the HDMI connector pinout information
> in the listing.
>
> The big ugly “plate” turns out to be easily removed from the assembly.
> That leaves you with a nice die cast box that is roughly 3 x 2.5 x 1”. It
> mounts to the plate via 4 small screws.
>
> Since you have a cable that fits the round connector, wiring it up to this or
> that should be pretty easy.
>
> Yes, the price keeps climbing ….
>
> Bob
>
>> On Jan 19, 2021, at 2:43 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
>>
>> Hi
>>
>> I don’t know if anybody else bought any of these or not.
>>
>>> On Jan 9, 2021, at 10:20 PM, Bob kb8tq <kb8tq at n1k.org <mailto:kb8tq at n1k.org>> wrote:
>>>
>>> Hi
>>>
>>> Just for the sake of listing all the variations:
>>>
>>> https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 <https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649>
>>>
>>> Is the M8T on what I would *guess* is the original board. Simply from looking at the picture I think
>>> you can guess pretty well what’s what on the board.
>>>
>>> Hint: If you buy quite a few …. errr … 10 … there s a pretty good chance that something more than
>>> 20% might get knocked off the price …. I bought a pretty large pile of stuff so it’s not clear if that
>>> had some impact on what offers got accepted …..
>>>
>>> If that’s not your favorite RF connector on the board, there are SMA’s that likely fit in the same footprint.
>>>
>>> Bob
>>
>> If you did, the link now goes to a new auction (at a higher price).
>> That auction shows the board in it’s proper enclosure and provides a bit
>> more ( but not quite all) information on the module. Since they are now
>> free shipping a much heavier gizmo, that might explain some of the
>> price increase.
>>
>> If you look at the box, the connector on that box most certainly is not an
>> HDMI connector. However it *does* tell you what signals are running around.
>> You have the PPS out on RS-422. You also get the serial out of the module
>> on another RS-422 pair.
>>
>> The clock in / clock out stuff … no idea. The EXT-INT pin on the M8T is driven
>> by the 8051 CPU on the board. It’s a good bet that’s what those clocks are getting to.
>>
>> The TI switcher chip on the board has it’s input clamped at 20V. It puts out 6.2V. No
>> idea what the correct input is. It seemed to be very happy with the 15V I put on it.
>> Pin 1 on J1 is power in. Pin 6 on J2 is ground. Ground also shows up on one of
>> the mounting holes. The other pins on J2 appear to be 3 RS-422 pairs.
>>
>> All of the I/O lines are protected with clamp diodes. The antenna has multiple
>> layers of protection. The debug pins on the C8051F320 come out to a connector
>> that may or may not be populated on this or that board. There is a flash chip on
>> the back side and an EEPROM on the front. If somebody was more ambitious
>> than I am, reprogramming the MCU to do fancy stuff might be possible.
>>
>> Fun !!!
>>
>> Bob
>
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