Thats interesting and yes I've seen uhf varicaps operate at that voltage before.
Which gives me another idea, I found a site that explains how to use the same i2c tuner can as I have, but it doesnt use 30v, just 5v supply, I was thinking it'd have an inverter inside or something, but when I just checked the datasheet it does indeed have a 30v supply pin, and the schem for the telly says the pin has 30v unregulated, so theres probably a reg inside the can but not an inverter.
So I'll try and test it agian when I get home today, and this time with a 30v supply, I noticed that it received the 1kc tone if I tuned the rf gen to 150mc, which is probably the top end of band 1, which without 30v is probably all you'd get regardless of the tunign words.