I posted this to TDPRI and didn't get a lot of response, so I'm trying again here.

My man cave has MV spot lights that generate a fair amount of near-white rf noise. I've found that the pitch this generates in the amp, via the pickups, can tell me quite a lot about the the pickups and amplification chain. For example, effectiveness of shielding, treble roll-off or the pickup's approximate resonance peak. Things like pickup brightness or treble loss in an OD stomp are IMO much easier to appreciate from the rf noise than from a musical tone.

Here's an example:


This is a sound clip of an SD jazz pickup with series/single parallel switching. The first half is rf noise greatly amplified, in three segments. The first segment is series, the loud second segment is single and the last quiet segment is parallel. The 50-cycle overlay can also be heard in the single segment. The second half is a note being played in the same three switch positions. There is not much difference in tone, but the recording is compressed and fairly low-fi. Through an amp, the series position is louder and smoother, but the single and parallel are very similar in both volume and tonal quality.

So what I would like is a little black box radio transmitter that will generate this kind of rf noise in my workshop, preferably with more power than my MV spots. I've done searches, and the closest I get are expensive mobile phone blockers.

Any suggestions? A circuit would do, or an electronics forum where someone might know.

Generating white noise isn't an issue -- there are iPhone apps that will do that all day, and RTAs for the same devices. I just don't know what would put out that sound THROUGH a guitar pickup.

You're not getting that RF through the pickup coils, necessarily, by themselves. Chances are you're listening to the entire rig (capacitors, strings as antennae, pots, cable, etc.) and that the resultant information ends up not being pickup-specific or usable in any intelligent way.
Thanks. Yeah, I can find plenty of info on generating white noise sound, but not radio transmitters. As you say, it won't just be confined to the pickups. - If it was a small box I could move it around like a geiger counter and maybe pinpoint the problem. The change in noise in the audio clip must have come from the pickup switching, since that was the only variable.