I don't have access to anything over 1GHz myself, so I will be contributing some related stuff now and then like i did yesterday.
I would not stress about not having any gear over 1GHz. It's just as easy to test your oscillators and do it REALLY cheap.
The first thing you probably already have. A USB TV dongle. Run some SDR software and you have a spectrum analyser that is good up to almost 2GHz. For only $20 !
The next thing to do is get your hands on some downconverters. Again, you probably already have these things.
The first is a satellite TV receiver. They're good to 2GHz. The IF stages also make good spectrum analysers on their own.
Those old MMDS antennas. The downconverters on them have a local oscillator of 1950MHz. They will give you access up to 3GHz, especially if you remove any front end filtering.
Next is a C Band satellite LNC. They're good for 3GHz to 4.5GHz. Again, if you have an older on you don't mind removing the front end filtering, you can push them out to 5GHz.
Next is 10GHz. If you have an old automatic door motion detector, a radar detector, or a burgular alarm microwave motion detector.
That will give you access to ~9-11GHz.
Ku Band LNC's, they're give you access to 9-13GHz and you can modify them well out to 15GHz. I've got an old Plessey 2.2dB NF LNC that I pushed out past 15GHz. (trying to get to 24GHz).
K Band Radar detector will give you 24GHz and some of the images. 24GHz gunn modules, you can mix them down and run them on your CRO or SDR.
And even then, you can still go dumb as a box of hammers simple diode wavemeter.
Two wires in parallel with a diode on the end connected to your CRO with a slow sweep looking for tiny changes in DC.
Connect the signal source to the diode and short the two wires. Move the short up and down the wires and look for nulls and peaks.
Measure the intervals which will be half wavelength. That's what we used to do in the days before rectum paralysers became dirt cheap.