This is the old version of the FETProbe, with limited supply voltage range.

Sold at a discount, while stock lasts. For the newer V2, visit https://www.tindie.com/products/makerprobe/1300-mhz-fetprobe-v2/

What is it?

A 1.3 GHz active scope Probe with FET input and very low input capacitance (about 0.3 pF)

• AC coupled
• minimum frequency: 100 kHz
• attenuation 1:10 (1:20 with 50 Ohm termination)
• supply with 5V, u.Fl
• reverse voltage protection
• output through u.Fl
• can be soldered directly to the device under test for minimal lead inductance

For powering, see https://www.tindie.com/products/makerprobe/usb-5v-to-sma-dongle/ - also available as an accessory option on this page

This is a nice low-cost addition to your scope accessory arsenal for cases when the stock probes of a cheap oscilloscope just can't do the job.

Why did you make it?

I made this probe to measure oscillators with low load capacitance, when my stock oscilloscope probes would probably detune the circuit too much.

See here for a little example: https://hackaday.io/project/184924-diy-13-ghz-fet-probe/log/213125-measuring-an-sx1280s-oscillator-frequency