For some reason I don't understand why folks think that spy transmissions must be out side of an amateur band...
Who thinks such transmission must be outside the ham bands? I often see known spy numbers transmissions inside the ham bands.
Clandestine transmissions could, and are, found anyplace within the spectrum.
If you are talking about clandestines masquerading as ham traffic, that is a different matter.
Think about it... if you wanted to 'hide' a transmission' say in CW... where would be the best place to hide it....?
CW is, let's face it, old tech, so if you wanted to 'hide' it what better place than in an amateur radio band.?
As I said on another board... if you want to hide a tree... hide it in the forest...
The CW sections of the ham bands are too narrow and constrained. When an unusual transmission occurs in the area it is pretty sure someone will notice it. Now, will anything be done about it? That is a different question. But if it is noticed that proves it can be noticed.
CW is relatively easy to machine monitor, multiple transmissions can be easily monitored and demodulated, take for example CW Skimmer. How difficult do you think it would be for an intelligence asset to develop such a technique that could specifically look for unusual or outlier traffic?
Going back to numbers traffic, I have seen known CW numbers stations inside ham bands, and it took very little effort to determine they were “different” from the surrounding ham traffic. Even without monitoring the exact traffic the visual differences on the waterfall (visually longer characters, all being numbers) were noticeable.
That doesn't take a hell of a lot of logic to understand... or maybe I am so far twisted that I don't get it...
But... I think I have it right.... even SSB can be 'hidden' within an amateur band so it wouldn't bring much attention...
If any of you folks think I am wrong then please sound your voices loud and let me know...
But understand, how many of you/us/me/etc know languages to the point where we can be sure. I have heard so many different languages using "K" or "W" or "A" callsigns that are using different languages who/whom can be sure?
Using unusual languages among anticipated or known languages is a sure way to draw attention, in my opinion. When I hear an unusual language on the ham bands I make SURE to listen for a bit, just to see what it is. Again going back to security apparatuses, things that stand out get noticed, and it is pretty easy (at military / government funding levels) to design monitoring software to queue on signals that do not match patterns, including odd languages.
Either hide it in plain sight with little or nothing to differentiate it from its fellow traffic (trying to mimic the other traffic very closely), or find security through obscurity, using frequencies and modes in locations that are not anticipated or obscured by other things. The example presented, CW in a MW BC station sideband, is pretty much what I am talking about. Maybe a digital signal in the sideband of a DTV signal, a PSK signal in the sideband of an FM BC signal, etc.
30 years ago such activity would have been less likely to be noticed. Even at the military / government levels wide band spectral displays and waterfalls were not in common use (although they were available, I used them as early as 35+ years ago) for monitoring receivers. Now, however, they are the norm. Once someone with those assets are looking for you they will find you…period. It is just a matter of how actively they are looking.
T!