Being cryptic is frowned upon here.
If you kow something just say it.
If you don't say it, we'll assume you don't know.
Q has stated that NSA records everything. It's certainly technically feasible. I presume they monitor the entire EM spectrum in such a way that they capture all transmissions of every kind everywhere.
There you are wrong.
All it takes are 3 receiving locations to triangulate a radio transmission.
Also if Nellie et al. follow the rules of their ham license, they have to identify themselves regularly.
We don't know yet if they were transmitting or just listening, we don't know what frequency and mode, we don't know if they took advantage of the repeater systems in that part of VA, we don't know if they accessed the linked repeater system that was connected to Chicago, etc. (Those long-distance links for VHF/UHF voice pass over the internet, BTW, which are most certainly monitored by NSA.)
It's possible they could have actually been using a modulation mode that (illegally) encoded their transmissions. It's also possible they spoke openly but the phrases they spoke were references to a code book that each party possessed. If they spoke openly on the repeaters, dozens or hundreds of other hams likely heard their conversations. Also there are public web sites that carry all the repeater traffic in different areas. Radioreference.com etc.
It's an unjustified leap to assume that the data architecture of their communications was that of a numbers station.
Correct, SDR.
If NSA is set up to monitor the entire EM spectrum everywhere, they would have many monitoring locations with many different antennas to acquire to different parts of the spectrum. They would have massive , realtime, data capacity. They would have a means to timestamp and merge data collected at different locations, and analyze it in near real-time. That means transcoders to decode each different mode including spread-spectrum and frequency-hopping (modulation techniques that are widely used in cellular telephony). I'm just inferring this based on what would be technically required, and assuming they do in fact do it. Perhaps from satellites they also have monitoring capability that we terrestrials lack.