Version 1.1 Duplex board gets populated

A project log for Cell Phone 4G LTE Repeater / Booster / Femtocell

An outside pole mounted aerial picks up 4G signals which are then filtered, amplified and re-transmitted through a second inside aerial.

Tegwyn☠TwmffatTegwyn☠Twmffat 08/20/2017 at 14:081 Comment

Even with my manual PNP machine, it took a gruelling 6 hours to populate this board below, taking great care to make sure the exact amount of solder was smeared onto the PCB before placing components ..... and still one of the main chips did not work! Thankfully, there are 4 'intercept' points that make the gadget really easy to de-bug and, yes, the VGA worked really nicely on Base Tx frequencies, even though the LNA was bypassed.

It's been a slightly frustrating couple of days, but I did discover 2 fairly serious errors, one of which I corrected with 2 pieces of bare wire. The other mistake was to try and control the LNA's using 5v instead of the recommended 3v - obviously I missed that somehow! Maybe this is why the LNA did not work, rather than bad soldering? Strangely, it did work on the previous incarnation with 5v.

No more work has been done on the LimeSDR this side of the Atlantic although Axeman has picked up my limesuite band 20 .ini file and made certain improvements to it in the USA.

In preparation for creating a Verizon band 13 version, I managed, with the help of Rickardas Jonaitis from Lime Microststems, to create an Arduino controlled signal generator using the LimeSDR. There is no band 13 in the UK and so frequencies have to be generated artificially to test the circuits. The pressure is now on to try and create 3 working prototypes for the Hackaday 2017 finals with the chance to win $50,000. Two months to go!

In the meantime, a short video is being prepared to clarify what the project is about and what the possible solutions are for the BT hackathon final. The actual project challenges seem to be changing fairly rapidly as new information is uncovered or old barriers are pushed through. Currently, the challenge seems to be 'how to safely transmit to the base station without making it crash'. Apparently, gleaned from an expert in the realm of repeaters, noise is a big issue and trying to up convert and down convert should be avoided if at all possible. Maybe simplicity is the answer after all?

Version 1.2 goes to Elecrow PCB service for manufacturing tomorrow.


Pero wrote 08/21/2017 at 20:04 point

Congrats, dude, great job!

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