DIY 1000 MW 2.4 GHz RF Amplifier

I was looking to increase my RC link range. I stumbled upon commercially avalible 2.4 GHz RF amplifies. But where is the fun in buying one, so I decided to make my own. It is based around SKY65162-70LF an IC from Skyworks. It offers low cost, wide frequency operation range and is suited for both 900mHz and 2.4gHz which are both very popular in the RC comunity.

Warning: In some countries you are required a HAM radio licence to operate with 1000 mW on 2.4 GHz band.

Supplies

- PCB =~ 0,5€

- SKY65162-70LF =~ 2,93 €

- Passive components =~ 1,5€

- 1x 0402 0.8 pF

- 1x 0402 0.7 pF

- 2x 0402 1.5 pF

- 1x 0603 7 nH

- 1x 0603 10 nF

- 1x 0603 1 uF

- RF connectors

- 2x Adafruit sma PCB connector

OR

- 1x Chinese sma PCB connector

- Aluminium housing

The cost of the amplifier shouldn't exceed 10€

Bill of materials in sheet form

Step 1: Schematics

I created the schematics based on amplifiers typical aplication which also offers component values for its operation bands. This instructable shows steps for building your own 2,4 GHz amplifier but with minimal thinkering it can be adapted to 900 MHz band.

Step 2: PCB

designed a 4 layer pcb following the manufacturers sample design found in the datasheet.

I calculated the prefered 50Ω impedace between first and second layer with the Saturn PCB toolkit using the PCB manufacturers PCB stackup. For 2.4ghz I calculated the track width to be 13,5 mils.

For PCB manufaturing I arranged my designes in an array to maximize the PCB quantity that I could acquire for the same price.

Gerber files are avalible here

Step 3: Soldering the Components

Now that we have our PCBs it is time to solder the components. Tiny 0402 components are quite fiddly to work with so a steady hand is a must. I recommend a small soldering iron tip and good quality tweezers.

Step 4: Making the Aluminium Enclousure

The PCB would operate as is but every RF PCB must have a good quality metal enclousure that ensures proper RF isolation and protects other electronics.

I designed mine and cut in on my CNC router. The bottom housing is made from 6mm thick aluminium sheet. The top is made from 3mm thick aluminium sheet.

I also engraved text that shows the input and output of the amplifier. To achive painting only the letters I spay painted the top hounsing and then sanded the paint off that it only stays in the letters.

Step 5: Finished

Just like that the DIY 1000 mW 2.4 GHz RF Amplifier is finished. I will be using it with my RC transmitter to get increased range.

Step 6: Performance Test

I tested my amplifier using my micro whoop drone. The value in the center of the screen idicates signal strenght from 0-100 (RSSI). The results are impressive because before the RC link was limiting the range but now the limiting factor is the video link while RSSI is never dipping below 80.