Interesting. How flat are they, though? I'm less concerned about them going beyond rated 3dB and more concerned about significant peaks and valleys within the operating range.
Ok Ok, will improve my setup and produce some proper results with screenshot and everything
Ok, so there it is. I tested the frequency response of 9 probes.
Table of content:(Including previous tests)
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Part 1, Batch 1 Frequency responsePart 2, Batch 1 Fast pulsePart 3, Batch 2 Frequency responsePart 4, Batch 2 Fast pulsePart 5, Batch 3 Frequency responsePart 6, Batch 3 Fast pulse
The Setup:I used a noise source to generate a signal from DC to 500Mhz. The impedance of the source being 50Ohms, a 50Ohms Terminator was connected directly on the output of the noise source. The probe under test was connected to the termination with a bnc-to-probe adapter. The other end of the probe was connected to an Oscilloscope (Lecroy DDA-110, 4GS/s, 1Ghz bandwidth).
Kuman P6100 100Mhz:I think I bought this probe on Amazon. Physically identical to the other P6100 probes. In term of flatness the P6100 is the worst.
Frequency response of the Kuman P6100 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
JinHao P6100 100Mhz:Similar to the Kuman P6100. But for some reason with a little bit more attenuation. Still, the frequency response is strangely similar to the Kuman P6100.
Frequency response of the JinHao P6100 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
NoName Chinese P6500 500MhzLook like a clone of the Tektronix P6139B. Physically the P6500 is really nice. I don't think the cable is silicon but it's quite flexible. The tip is also gold plated. Frequency response is fairly strait with a bump at around 225Mhz.
Frequency response of the P6500 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
Cleqee P4100 100Mhz 100x:Probably the worst probe I have. Do not follow the reference and is probably not doing 100Mhz.
Frequency response of the P4100 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
Hantek T3100 100Mhz 100x:The Hantek T3100 look well constructed. and seem to perform well up to 250Mhz.
Frequency response of the T3100 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
Tektronix P6106 250Mhz:Overall really good performance.
Frequency response of the P6106 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
Tektronix P6054a 150MhzThe P6054a seem to exceed his frequency rating.
Frequency response of the P6054a (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
Tektronix P6056 3.5Ghz 50OhmsFrequency response of the P6056 (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.
60dbm.com Active Probe 1Ghz 50OhmsBought this probe on ebay (
https://www.ebay.ca/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope/332884643332?hash=item4d81788e04:g:CzsAAOSwWlNZzA4E) a while ago but never really had the time to test it properly. Look like the design was inspired by a article published in Elektor magazine in 2004 (
https://elektrotanya.com/files/forum/2009/10/e04a036.pdf). Overall the probe perform really well up to 800Mhz. The 5dBm attenuation is normal.
Frequency response of the Active Probe (Green) from DC to 500Mhz, 50Mhz per division. Noise source in Cyan.