Long term test of analogue circuits

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.

capt-flatus-oflahertyCapt. Flatus O'Flaherty ☠ 06/08/2017 at 17:160 Comments

Since I actually need a 4G signal repeater in my office, I decided to run a more long term test of one of my analogue boards - a Low noise amplifier, the QPL9065.

With my plate antenna positioned 1/2m away from my phone I was able to get a consistent 20 dBm increase in signal strength and a reliable 4G data connection. I felt so confident that it was going to work that I used it to run/assist an important conference call with some of the guys from BT, Facebook and Lime Microsystems. There's nothing quite like working under pressure!

In the background of the photo above can be seen the LimeSDR with it's incredibly powerful LMS7002M chip. This chip contains all the necessary blocks that I need to complete this project but there are a few barriers that prevent me from using it namely:

  1. There's no breakout board for this chip alone unless I backstep to it's predecessor, the LMS6000.
  2. It requires a 6 layer PCB.
  3. KiCAD PCB design files are not available yet.
  4. Many functions are routed through the FPGA which prevents me from using them directly.
  5. Learning to use the FPGA is another steep learning curve.