Down Sampling is magic.

[VK3YNV]

 

[VK3ZYZ]

That is pretty cool. So simple. We has a sampling CRO on a trolley at Radio Australia years ago. I think it may have been 5GHz. It was a BIG CRO!

 

[VK3ZYZ]

I see that was just featured on hackaday.com too......

The Magic Of A Diode Sampler To Increase Oscilloscope Bandwidth

Making an oscilloscope is relatively easy, while making a very fast oscilloscope is hard. There’s a trick that converts a mundane instrument into a very fast one, it’s been around since…

hackaday.com

Maybe a good project, an Arduino with an Si5351 and a few bits?????