Re: Fast probe prices?

Jonathan Pyle

Charles --

I tested the RF probe from Ukraine that I got on eBay (

I tested it with my 1S1 and my Leo Bodnar 30 picosecond pulse generator (10 MHz) and found that the measured risetime through the RF probe was around 300 picoseconds, which is the same as when the pulse generator is plugged directly into the 1S1.

However, the RF probe did add a lot of "ringing" to the waveform. See the photo in this album:

I'm not sure this is a fair test, though, because a 30 picosecond risetime contains frequencies well beyond the stated bandwidth of the probe (1.5 GHz), so maybe that messes things up?

The RF probe comes with a nice telescoping needle probe point, but I desoldered it because I thought it might introduce noise. Removing it did not have any noticeable effect. I soldered an SMA socket to the RF probe input for purposes of attaching the pulse generator without any long leads. (The pulse generator wants 50 ohms so I used a T and a 50 ohm terminator.)

I did another test with a 10MHz signal from my Koolertron function generator (low cost Amazon product) through a 3-foot BNC cable (well within the bandwidth of the probe). The waveform looks the same through the RF probe, just noisier.

I don't have a function generator that can produce frequencies in the hundreds of MHz, and I don't have a spectrum analyzer that can test the frequency response of the RF probe (see the eevblog post above).

For $21.20 including shipping I think it's a pretty handy device. (Shipping to the U.S. took only eight days.)

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