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 < [email protected]> 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 <[email protected]> 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 < > > [email protected]> 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 <[email protected]> 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 -- [email protected] -- To unsubscribe > >> send an email to [email protected] > >>> To unsubscribe, go to and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] -- To unsubscribe > send > >> an email to [email protected] > >> To unsubscribe, go to and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] -- To unsubscribe > send an email to [email protected] > > To unsubscribe, go to and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
