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

[paul swed]

John
I suspect we may be the only ones interested in these units. Can we connect
offline?
I am at paulswedb at gmail.com.

With respect to Murphey Surplus they have been around for 30+ years. I
think if you reach out to them they will take care of the issue of
wrong/bad units. I have one damaged top connector. No real need to fix that.

USB you need a USB driver to use it. Will reach out to Ublox to see if a
32/64 bit may be available.

With respect to wire on the next unit for TX1/RX1 plan to use 34 gauge wire
nice and flexible. This particular stuff is supposed to be solderable. Will
see.
Regards
Paul
Regards
Paul

On Wed, Apr 6, 2022 at 7:08 PM paul swed <paulswedb at gmail.com> wrote:

> 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
>> >>> _______________________________________________
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