[time-nuts] Re: Ublox LEA-4T mentioned here. Have fired one up

[paul swed]

John your pins are correct. I am thinking about 3 and 1 for ttl rs 232 from
tx1/rx1.
Though I really need to try usb, maybe no need to screw with tacking wires
on.
I have found the chip by the top connector. Its a L-band switch. Doesn't
make sense but what can I say. Also removed the 3.5V glob board this
afternoon.
As far as the connector goes I acquired connectors and cables at hamfests
years ago.
So that made it easy.
Regards
Paul



On Wed, Apr 6, 2022 at 6:15 PM John Miller via time-nuts <
time-nuts at lists.febo.com> wrote:

> Paul,
> Thanks again for the addition info - very helpful. Mine came in this
> afternoon
> and unfortunately only three of them are LEA-4Ts, the other two are Leadtek
> LR9548S SiRF StarIII based modules, one of which has a sticker that reads
> "short" on it. I could request a partial refund but the seller probably
> just had
> no idea.
>
> From my own continuity testing (I haven't powered them up yet) I have
> determined the following pinout. With the boards in "vertical" orientation,
> pin 1 is the leftmost pin. It's also the square pin on the footprint.
>
> 1 - NC
> 2 - Vcc/VDDUSB (3v)
> 3 - NC or 3v for LNA power if sub-board is present
> 4 - USB DM
> 5 - USB DP
> 6 - PPS
> 7 - GND
> 8 - NC
>
> My next step is to find my 30AWG wire-wrap wire and tack wires straight to
> the module, then figure out how to get an antenna connected. I don't think
> I
> have any adapters this small.
>
> John
>
>
>
>
> > On Apr 6, 2022, at 1:09 PM, paul swed <paulswedb at gmail.com> wrote:
> >
> > John indeed on the 3V. I have lots of 3.3V regs. Not sure I have a 3. But
> > like you I am thinking the same only maybe simpler. Simply solder it to a
> > piece of copper board thats larger so I can mount interface chips drill
> > holes for screws and such. Also some standoffs for 1pps, ext in/out,
> rs232
> > tx1/rx1. Smaller wires are the way to go on connecting to the pins. At 3V
> > startup is 65ma settles to 57ma. The input is a bit odd. Like you I
> spotted
> > the mcl combiner/splitter. The side port is 4-5 db hotter than the top
> > port. But both work. So its a bit odd as if it was intended for 2
> antennas.
> > Kind of doesn't really matter as its totally working on the TX1/RX1
> port. I
> > set it to 115200 baud. It comes up 9600. That change is sort of silly.
> > Thinking about mounting the board on the copper board component side
> down.
> > Easy to solder copper support wires then. No screw holes kind of a pain.
> > While soldering I have a small tip iron and found it really needs to be
> at
> > 700 F or so to do good job.
> > On one of my units and in the ebay pix there is a spot of tape that holds
> > down I assume a small regulator and TCXO. But it really doesn't seem to
> do
> > anything. Four of my units do not have that mod. So have not really
> figured
> > it out yet.
> > Good luck.
> > Paul
> >
> > On Wed, Apr 6, 2022 at 12:51 PM John Miller via time-nuts <
> > time-nuts at lists.febo.com> wrote:
> >
> >> Hi Paul,
> >> Thanks for sharing this info! I ordered one of these lots as well, and
> it
> >> should arrive today, actually. My intention is to re-mount the modules
> on
> >> more sensible breakout boards, maybe a Pi Hat.
> >>
> >> The 8 pin chip on the board is an MCL BP2G. RF power combiner/splitter
> >> https://www.minicircuits.com/pdfs/BP2G+.pdf <
> >> https://www.minicircuits.com/pdfs/BP2G+.pdf>
> >>
> >> If I am reading the datasheet and board layout right, the top connector
> is
> >> connected to PORT1, the GPS is PORT2, and the side connector is SUM. I
> >> would imagine that the GPS would be on SUM if the idea was to feed in
> >1 RF
> >> signal, but maybe I am misunderstanding it?
> >>
> >> I was surprised by your note that the USB voltage input is 3v, but after
> >> checking the LEA-4x datasheet, sure enough, 3.6v max. I thought all USB
> had
> >> to be 5v?
> >>
> >> Finally, it looks like the PCB is ceramic, rather than normal
> >> epoxy/fiberglass. Hopefully that doesn't make removing the modules any
> more
> >> difficult...
> >>
> >> John
> >>
> >>> On Apr 5, 2022, at 9:14 PM, paul swed <paulswedb at gmail.com> wrote:
> >>>
> >>> Hello to the group.
> >>> Gregory had mentioned a deal on Ebay for 5 X LEA-4T receivers at $25.
> >>> Seemed like an OK deal to be able to have a few units around for
> >>> experimenting.
> >>> They arrived and were easy to get operational.
> >>> They are a little different. The module actually has 2 antenna inputs.
> >> Took
> >>> a bit to figure out what was going on. Both work in the L1 band and the
> >>> side connector appears more sensitive by 4-5 db. But both work.
> >>> Its a circa 2006 16 channel receiver and does capture WAAS.
> >>> Locks in about 30 second from cold start. Ublox u-center 8.18 works
> fine
> >>> with the unit.
> >>> Its setup for USB. But that USB is just 3V logic so be careful.
> >>> The unit runs on 3V. None of the ttl 3V rs 232 ports connect to
> anything.
> >>> But TX1/RX1 actually have control and data at 9600 baud. Pins 3-4 on
> the
> >>> actual chip. Attaching some small wires allowed complete control of the
> >>> module after passing through a logic to usb serial converter.
> >>> 1 PPS works just fine but have not compared it to anything.
> >>> So for me at least the $5 wonders will be fine.
> >>> Regards
> >>> Paul
> >>> WB8TSL
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe
> >> send an email to time-nuts-leave at lists.febo.com
> >>> To unsubscribe, go to and follow the instructions there.
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe
> send
> >> an email to time-nuts-leave at lists.febo.com
> >> To unsubscribe, go to and follow the instructions there.
> >>
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe
> send an email to time-nuts-leave at lists.febo.com
> > To unsubscribe, go to and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe send
> an email to time-nuts-leave at lists.febo.com
> To unsubscribe, go to and follow the instructions there.
>