Ah yes, the 608D and F, I spent many an hour with those. We had some with the PLL external "lock boxes" on them.
Speaking of the FM pirate use, I used to work in a place in East Rochester NY during my college breaks where the PA system, which told you when you had incoming phone calls and what line to use etc, spent the rest of it's time dispensing elevator music from the local EZ listening station, WEZO - whether you wanted to listen or not. Yuck! Worse, they only had one tape, so you listened to the same songs by the same people at the same time of day over and over and over. It was sort of like Groundhog day, you could set your watch to Celito Lindo being butchered by the Thousand Strings Orchestra at 10:10 each morning. After a few months of this, I had had it and was looking for a way to MAKE IT STOP before I totally lost it. We had a few spare 608's sitting on the shelf waiting for something to do. Hmmmmm....
Unscrew the ruby red pilot lamp on the front. Snake a piece of #32 magnet wire a few wavelengths long into the output connector and Voila! Silence! The sig gen captured the FM receiver downstairs full quieting. Much consternation in the front office. A few frantic phone calls to the station insisting that they *must* be off the air, we can't hear you. Sadly, there was a backup EZ listening station on the dial which was tuned in within the hour to replace the missing "EZO". Happily, there were TWO 608's looking for something to do.
For the next week, there was a constant stream of different radio stations on the PA system as they hunted around trying to find something to replace the missing elevator music. Country/Western, Rock (yeah!), Gospel, whatever, but none of it met their requirements. But a lot of folks were enjoying the change in music down on the prodcution line and elsewhere.
Finally the plant manager got suspicious of "those engineers" and started skulking around in the lab looking into corners. I don't think he'd have ever figured it out but my boss noticed Don and I about splitting our faces trying to keep the grins off and got the story out of us. He waited the till manager was gone and then made us take down the signals. My only regret is that we didn't bring in a tape deck or something to feed to the FM modulation port to put our own choice of music on for a while.
I'll always have fond memories of the 608.