RF Probe
Welcome reader.
A big thank you to Peter for all the information he has given me to build this project.
As always, we need to know what a Radio Frequency probe does. An RF probe is a device which allows electronic test equipment to measure radio frequency signals in an electronic circuit.
The RF probe connects to any multi-meter to measure the RF - No fancy equipment needed.
The RF probe is quite easy to make and only needs a few components which cost pennies.
This project is excellent for beginners!
Click this text to go to the website I purchased my components from
What you will need:
• A Multi-meter of some sort (any will work if it has a 10V range)
• A ball point pen that you are willing to sacrifice with a inner diameter of at least 1cm to fit the components inside
•
4cm of some sort of copper / brass rod (I used the center core of a RG58 coax cable)
• A 10nF ceramic capacitor
• A 1nF ceramic capacitor
• 2 Diodes (1N5819 schottky diodes which are the ones I used but for better sensitivity use the N34A germanium diodes)
• 2 connectors of your choice that will fit your multi-meter
• Some thin wire (I used a UK plug socket wire)
• A crocodile clip
• Some heat shrink (optional but recommended to stop short circuits)
Lets start building!
1. Making the probe tip:
First of all we need to make the tip of the probe. I made mine by removing the center core of some RG58 coax and then using a soldering iron to cover the copper entirely in solder. This will be the part which we will probe with.
2. The electronics:
After you have covered your probe tip in solder we can begin to add the electrical components.
We can start by soldering on a 1nF capacitor onto the probe tip followed by one of the two diodes (with the grey strip on the diode facing outwards).
Next solder on another diode however this time have the grey strip facing towards the probe tip end.
Last but not least solder a 10nF capacitor between the legs of the two diodes and then connect two bits of wire to both ends of the diode legs (and apply heat shrink).
Gently slide the components into the pen casing making sure not to snap any of them.
On the same wire as the diode with the grey strip facing towards the probe tip cut a small section out and solder another wire to that section (and apply heat shrink as needed). On the end of this wire attach a crocodile clip. - This will be our grounding / earthing cable.
Finally on the end of the two remaining wires, solder on the correct connector to fit your multi-meter (in my case I soldered on banana connectors).