Author Topic: Ebay find. LEA-5T-high-precision-timing-GPS-module (Read 16993 times)

Deathwish · « **on:** August 15, 2015, 09:09:39 pm »

http://www.ebay.com/itm/UBLOX-LEA-5T-high-precision-timing-GPS-module-dev-board-1PPS-USB-RS232-ntp-ser-/251785217093

dkozel · « **Reply #1 on:** August 15, 2015, 10:45:10 pm »

Heh, the listing has a the seller's GPS coordinates down to the precise window I'd say.

Fraser · « **Reply #2 on:** August 15, 2015, 11:36:21 pm »

I bought a twin output 10MHz OCXO board from this seller. Good service, well packed and a nicely produced custom PCB with all the required supply conditioning etc. Good value for money IMHO.

Aurora

Deathwish · « **Reply #3 on:** August 15, 2015, 11:40:27 pm »

Did you get hit for customs ?. its the only thing that puts me off buying

Deathwish · « **Reply #4 on:** August 16, 2015, 12:00:45 am »

Quote from: Aurora on August 15, 2015, 11:36:21 pm

I bought a twin output 10MHz OCXO board from this seller. Good service, well packed and a nicely produced custom PCB with all the required supply conditioning etc. Good value for money IMHO.

Aurora

I just clicked buy it now on one of those. I now wait for customs to hit me

Vgkid · « **Reply #5 on:** August 16, 2015, 06:33:31 am »

I have s slightly different module, that uses the 6T, uses u.fl for timepulse1, ans sma for tp2.

max666 · « **Reply #6 on:** August 16, 2015, 08:07:56 am »

Quote from: Deathwish on August 15, 2015, 11:40:27 pm

Did you get hit for customs ?. its the only thing that puts me off buying

I would imagine that depends a lot on the country you are in. I ordered one just now, and based on my personal china ebay experience, I don't expect to hear from customs.

But I would love to hear what others think about the unit as a precision timing module.

dexters_lab · « **Reply #7 on:** August 16, 2015, 10:20:28 am »

Quote from: Deathwish on August 15, 2015, 11:40:27 pm

Did you get hit for customs ?. its the only thing that puts me off buying

if it's sent in the post there is a good chance you'll miss the VAT/Duty/Release fees on something that small

Fraser · « **Reply #8 on:** August 16, 2015, 03:17:59 pm »

I received no charges for VAT. I will say no more but it all depends what the seller write son the CN22.

Aurora

Deathwish · « **Reply #9 on:** August 16, 2015, 05:11:20 pm »

I didnt get the sat card, I got the same ocxo you got from them, so who knows. I couldn't afford the sat card at present. But its on my list with the hundred other things

Actually I am getting a little confused as I purchased a LEA-4 and a AD9850 module with some intent in mind but I forget what it was all about now.

bitslice · « **Reply #10 on:** August 17, 2015, 10:14:42 am »

For those in the UK watching this in black and white, this appears to be similar?

http://www.ebay.co.uk/itm/Mtron-GPS-Module-M9101S-Military-Defence-Systems-1PPS-/161794282422?

I was hoping that nobody else had spotted it, but now it's at £31

ends today, so be quick.

Deathwish · « **Reply #11 on:** August 17, 2015, 10:37:35 am »

I like that, dont understand why it has the sat gps receiver on it but then I expect some nice person will explain it. I expect it to have a number of watchers now you have posted it...

bitslice · « **Reply #12 on:** August 17, 2015, 01:44:52 pm »

Quote from: Deathwish on August 17, 2015, 10:37:35 am

I like that, dont understand why it has the sat gps receiver on it

I think it is one of these
https://en.wikipedia.org/wiki/GPS_disciplined_oscillator

Vgkid · « **Reply #13 on:** August 17, 2015, 11:39:40 pm »

^^^ correct.
so did anyone here win it.

Deathwish · « **Reply #14 on:** August 18, 2015, 12:00:11 am »

not me. i never even bid on it

Deathwish · « **Reply #15 on:** August 22, 2015, 11:06:13 am »

Quote from: max666 on August 16, 2015, 08:07:56 am

Quote from: Deathwish on August 15, 2015, 11:40:27 pm
Did you get hit for customs ?. its the only thing that puts me off buying

I would imagine that depends a lot on the country you are in. I ordered one just now, and based on my personal china ebay experience, I don't expect to hear from customs.

But I would love to hear what others think about the unit as a precision timing module.

Mine came today, marked as commercial sample £12. Seller did me proud and I am well chuffed.

max666 · « **Reply #16 on:** August 24, 2015, 11:08:10 am »

Mine arrived today (no customs

)

Other than that what should I say? It works.
Just did a quick test by sticking a GPS antenna out a north facing window (pretty much a worst case scenario), but it didn't take too long to get a fix and the 1pps LED was happily blinking away.

Deathwish · « **Reply #17 on:** August 25, 2015, 06:42:09 am »

I got a notification mine is on it's way, however its a bit curious, as it has a wnDirect consignment number and looking at their web site ( I have never heard of them before ) they do not seem to ship FROM china but from the UK to other countries, it says retailer is wndirect, then gives their ref number but also another that says DM Consignment Code: DMC0C58U ... So I have no real idea where this is coming from. possibly he is shipping from within the UK somewhere as well as HK / China

Wuerstchenhund · « **Reply #18 on:** August 30, 2015, 09:07:12 am »

Quote from: Deathwish on August 25, 2015, 06:42:09 am

I got a notification mine is on it's way, however its a bit curious, as it has a wnDirect consignment number and looking at their web site ( I have never heard of them before )

wnDirect is owned by DPD and is pretty new in the UK but managed to get a lot of business in recent years (i.e. is the UK service used by ebay's GSP so if you order something from the US via GSP then it will end up with wnDirect). They don't do the actual delivery, though, as wnDirect doesn't have any physical delivery vehicles and relies on Yodel and other sub-contractors including one-man businesses instead. Also, wnDirect's tracking is pretty much hit and miss and often updates only several days after an item has been delivered.

I order quite a few things from abroad and never had any problems with wnDirect aside from the crap tracking, but then I didn't have to deal with them directly anyways.

Deathwish · « **Reply #19 on:** August 30, 2015, 10:12:17 am »

Thank you Wuerstchenhund

Robaroni · « **Reply #20 on:** May 07, 2016, 10:43:59 pm »

Anybody had this awhile? How's it work?

Thanks,
Rob

Gyro · « **Reply #21 on:** May 08, 2016, 11:50:16 am »

At the moment you might also want to consider one of the cheap LEA-6T modules. More effort required on your part - RS-232 level translation, output buffering etc. You do however get the benefit of TWO programmable time-pulse / frequency outputs.

https://www.eevblog.com/forum/projects/ebay-u-blox-lea-6t-gps-module-teardown-and-initial-test/msg886887/#msg886887

Depends on your application of course.

Edit: and check that you're getting a LEA-6T and not a NEO-6 or alternative part.

jpb · « **Reply #22 on:** May 08, 2016, 01:11:23 pm »

The Lea 5T module has been around for a while.

What put me off is it doesn't have the variable, up to 10MHz, clock output of the Lea-6T so it is only 1PPS (I think this is the case, I may be wrong - it is hard to find old data sheets on the LEA site which now has moved beyond the Lea6T even.)

mmagin · « **Reply #23 on:** May 08, 2016, 03:36:53 pm »

I have one of these boards. It seems to work fine. I put it in a case and use it for NTP on one of my computers (via a non-USB serial port for low latency.) The PPS signal seems to be usefully routed to the serial port for that purpose.

Robaroni · « **Reply #24 on:** May 08, 2016, 04:24:57 pm »

Hi,
I want to use it for a DO. I'm going to write a program to voltage adjust my Milliren 260 through a DAC. I can use a one second pulse or a 10Khz and a PPL.

jpb · « **Reply #25 on:** May 08, 2016, 06:18:47 pm »

Quote from: Robaroni on May 08, 2016, 04:24:57 pm

Hi,
I want to use it for a DO. I'm going to write a program to voltage adjust my Milliren 260 through a DAC. I can use a one second pulse or a 10Khz and a PPL.

Life would be simpler with the LEA-6T which has more flexible output and is available cheap currently as pointed out by Gyro (they are sold as part of a GPS compass system).

See this thread:
https://www.eevblog.com/forum/projects/my-u-blox-lea-6t-based-gpsdo-%28very-scruffy-initial-breadboard-stage%29/

Robaroni · « **Reply #26 on:** May 08, 2016, 10:31:47 pm »

I'm looking for 1E-11 to 1E-12, I don't think he got it that close.

Thanks for the link,
Rob

Gyro · « **Reply #27 on:** May 09, 2016, 09:15:06 am »

But that's because I'm not actually _trying_ to hit those figures at the moment - my focus has been on achieving the fastest possible start-up to 'useful' accuracy by using the highest PLL frequency possible.

The LEA-6T can do anything the 5T can do, and more. There's a useful u-blox timing app-note here:

https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf

Robaroni · « **Reply #28 on:** May 09, 2016, 01:34:24 pm »

I didn't buy the 5T.
Trouble is I want the simplest, cheapest solution possible. I guess I could get a 6T, make my own antenna, program it. etc. but all I really want is an accurate 1 sec pulse to compare with my rubidium every so often. The Milliren 260 and the Morion 89A really work well and the Milliren is touted to be up to rubidium standards. I built boards to 12 bit DAC precision control them through a Thevinen's equivalent circuit and I just checked the Milliren after about 4 or 5 mos. It was at 9.9999999998 compared to the last time I set it to the rubidium. So I turn on my rubidium once every six months set my OXCO's and shut it off after a day. It will probably last forever doing this and I have a couple of the Milliren 260's and one MV89A.

So bottom line, I already did all the work I want to do making the case and PCB. It was a fun project but I want to get back to making my ULE (Ultra low expansion) glass pendulum and other clocks and I only want the GPSDO to check the initial settings to see if I'm in the ball park and my rubidium isn't wacked!

I'm going to redo the boards (If anyone is interested). They work pretty good but I added the MV89A after I designed the initial circuit so I want to add a few more improvements to the final board.
The Milliren goes for about 30 bucks US on eBay but you have to watch getting bad ones and check them really well for a couple of days to make sure they hold up. If you use the internal voltage ref, make sure the ones you get don't drift.

The other problem with the Milliren is that eBay only seems to have 5 Meg versions so I used a Cypress chip to double the freq. Of course the Morion is 10Mhz so you don't need the Cypress.
Rob

Robaroni · « **Reply #29 on:** May 09, 2016, 01:41:45 pm »

Here's a built proto board with the Morion:

Gyro · « **Reply #30 on:** May 09, 2016, 06:19:04 pm »

That's impressive

As you say, you've done the hard work, and are well equipped to use just the 1pps.

The LEA-6T ebay module can easily be modified to output a 1pps signal down the existing cable as you've probably seen from the teardown. Programming via u-center s/w is easy and as the board includes both flash and ram backup battery, very easy to save to configuration. Being able to set the mark/space may or may not be useful to you.

You face the same quandary as I did - you either use the on-board patch antenna, mount the module somewhere high and buffer the 1pps signal down to where you want it (I assume you would want to buffer it to maintain timing edge integrity), or alternatively you modify it to use an external antenna.

This does seem to be the cheapest way to get the u-blox module at the moment.

Robaroni · « **Reply #31 on:** May 09, 2016, 06:37:42 pm »

Gyro,

I'll pick one up, thanks very much for the help and work you did to save the rest of us work!

Best,
Rob

texaspyro · « **Reply #32 on:** June 03, 2016, 05:26:12 am »

Quote from: jpb on May 08, 2016, 01:11:23 pm

The Lea 5T module has been around for a while.

What put me off is it doesn't have the variable, up to 10MHz, clock output of the Lea-6T so it is only 1PPS (I think this is the case, I may be wrong - it is hard to find old data sheets on the LEA site which now has moved beyond the Lea6T even.)

I just got in one of these boards and it does support two programmable pulse outputs. The data sheet says you can program the width and interval in 1uS steps. However, the data sheet does not say what range is acceptable. I have found for the LEA-5T that anything over 1 kHz causes the pulse to go crazy or stop and the module starts dropping messages and behaving erratically.

I found the LEA-5 protocol manual on (I think) Sparkfun. It covers the 5T specific messages.

texaspyro · « **Reply #33 on:** June 03, 2016, 05:43:08 am »

One other thing about the board... it reports an "antenna short" condition even with no antenna connection. The board is putting out the correct voltage on the antenna pin.

Also, I have the receiver configured to send time messages every second. Occasionally it seems to drop a time message. The dropped messages seem to come in clusters. I'm running an log overnight to see what it looks like in more detail.

Astralix · « **Reply #34 on:** April 24, 2019, 02:07:56 pm »

I know this is an old thread, but as eBay disabled almost all external links, it is hard to find all information about this module.

I wonder if someone still has some pinout of the module?
If the pin near the post hole is 1 I think this might be correct:

GND o o ?? PPS o o RxD ?? o o TxD Vcc o o ?? 1

Does anyone have the missing pins functions for me?

Thanks!

jpb · « **Reply #35 on:** April 24, 2019, 06:13:31 pm »

Quote from: Astralix on April 24, 2019, 02:07:56 pm

I know this is an old thread, but as eBay disabled almost all external links, it is hard to find all information about this module.

I wonder if someone still has some pinout of the module?
If the pin near the post hole is 1 I think this might be correct:

GND o o ?? PPS o o RxD ?? o o TxD Vcc o o ?? 1

Does anyone have the missing pins functions for me?

Thanks!

The best thing might be to trace connections to the module itself.
The Lea5T datasheet is a little hard to find now but the 6T is supposed to be backwardly compatible so should have the same pin-out:
https://www.u-blox.com/sites/default/files/products/documents/LEA-NEO-6T_ProductSummary_%28UBX-13003351%29.pdf

testpoint1 · « **Reply #36 on:** April 25, 2019, 02:00:29 am »

Quote from: Deathwish on August 15, 2015, 09:09:39 pm

http://www.ebay.com/itm/UBLOX-LEA-5T-high-precision-timing-GPS-module-dev-board-1PPS-USB-RS232-ntp-ser-/251785217093

5T and 6T is quite old for the 1pps timing, now can use the M8T, price is a little high if you use a second hand, 25 USD.

Astralix · « **Reply #37 on:** April 25, 2019, 10:24:27 am »

Oh, I use two stacked double-oven Trimble modules for my 10MHz hobby lab reference. That is by far enough to adjust, even calibrate any rig that shows up for repair on my bench.
But as these Trimble units are hard to contact (FFC cables and breakout boards required) and, if in good condition, relatively expensive, I thought just for playing around, I use one of these simple modules.

This LEA-5T was less then 20EUR and so it's a perfect board to play around with ublox configuration software, rtklib and building a nice Stratum-1 NTP server for my home. As soon as I have fittet the two Trimbles in their new case, I will probably use them to run the NTP over a little OrangePi as they are powered 24/7 anyway.

But thanks Deathwish, I found that picture of the pinning that was missing in my auction.


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: Ebay find. LEA-5T-high-precision-timing-GPS-module (Read 16993 times)

Share me