[NLRS] Test Plan for HT Transmit Quality up to 1300 MHz?

[Thomas Murphy]

Seeking VHF+ wisdom as alluded in the UV-K5 discussion: what does the 
test setup look like for HTs (and throw in transverters up to 10W) 
through 1300 MHz when working with a signal-level input spectrum 
analyzer? My concerns are second/third harmonics, then fundamental 
output power, then modulation quality. If you have your own setup to 
reference, that would be handy!

For background, I have access to a 7.5 GHz Tek USB spectrum analyzer at 
work (https://www.tek.com/en/products/spectrum-analyzers/rsa600) that, 
of course, will only work with a direct connection to your antenna port 
for your basic IoT sort of devices (+30 dBm > 10 MHz). I haven't figured 
where the best dynamic range for harmonic testing on this instrument is, 
but I'm hoping its flexible input attenuator helps keep that decent. I 
could probably check flatness with the unit's tracking generator, then 
see about loading correction factors.

The two techniques I've figured for appropriate sampling are external 
direct attenuation (power attenuator) and wideband RF sampler 
(non-directional) with external power termination on the through port. 
Of course, this being amateur and for my hacking project, I'm hoping to 
keep the additional equipment economical rather than laboratory grade 
(unless there's a deal on the right part!).

On the sampler side, there's either Bird or RF Industry variable 
samplers, then this one commercial non-directional sampler I can find: 
https://www.ebay.com/itm/NEW-DC-2GHz-40dB-ultra-wideband-RF-sampler-SMA-interface-/283235697566 
. Add a load and a bit more sampler attenuation to set the level.

I could also just go with a 10 W, 3 GHz, 30 dB attenuator (plus maybe 
pad that with one of my 1 W class signal attenuators from my nanoVNA 
kit). There are some nicer rated (12 or 18 GHz), manufacturer branded 
models out on eBay for maybe decent rates as used models.

Possibly overthinking it; looking forward to your input.

- Thomas / WN1C