FNIRSi 2C53T scope

The FNIRSi portable scope, model 2C53T, is just the thing for viewing FM tuning for those tuners which have scope outputs.  It costs around $100.  A two-channel model is required for this application, not one of the even cheaper ones.

The screen is tiny compared to my Rigol, and it lacks the dynamic measurements.  But it's small, cheap, and doesn't have a fan.

As small as the screen is, you are going to see more than you see on some (but not all) tuners that have scopes.  Notably the Sequerra Model One had a bigger scope, and with a super cool RF spectrum analyzer option.  The scope is about the same size as on a Marantz 10B, and larger than on a 20B.

It's good for tuning each station in precisely, as well as viewing multipath and other issues.

It has rechargeable batteries, but it works while you are charging (unless, they warn you, that you try to make measurements on the same computer motherboard which is supplying the power--in that case get another USB power supply or you can create a short).

The manual is so tiny as to be unreadable (download the online version).  Even then it's not very useful, and the device is as counter-intuitive as heck.  It took me 2 days to figure out how to use it as an X-Y scope for FM tuners.  Not that selecting X-Y was hard...that was the easiest part--it's at the top of the menu when you press the Menu button.

I made the mistake of starting up the unit without looking at the screen, and ended up selecting the Chinese characters.  Then just about anything was impossible.  Indecipherable messages could appear while the unit simply locked up.  Finally it seemed to resolve, but it took a long time.  (Apparently it was some kind of Calibration, and pressing other buttons as I did frantically only makes it take longer.)

"Calibrating"

But the key discovery was that you get to Settings not through the menu, but through the startup screen (where you can select Scope, Multimeter, Generator, or Settings).  Then, at the top of Settings, you can set (or re-set) the languages.  At the bottom of Settings you can do a full reset, which I did several times before I figured this thing out.

Then you have the issue of setting the sensitivity of Channel 1, Channel 2, the "H" parameter (bandwidth) and persistence.

It took me the longest time to figure this out:  Use the "Move" button to change from Channel 1 to Channel 2.  Then use the "Select" button to select what things you want to update (see the manual: one thing updates the sensitivity, another the offset).  Then use the up/down or left/right keys to actually do the update (each Select mode assigns different things to the up/down and left/right keys).