Miscellaneous Projects and Devices
20W Tube FM Transmitter
Tubes again? Well yes, I have built this device during my high school days in the 90's. The price of a decent RF output bipolar transistor was about $150 in these days, a crazy amount to pay for your amateur project when compared to overall conditions of living during that time. Not to mention the probability of your $150 going up in smoke in a millisecond because of a tiny fault during experimenting. Tubes, on the other hand were available, much more robust, more fun, and they worked and looked good.
2x ECC 88 - Audio amplifiersECF 82 - Modulator and RF VCO
EF 80 - RF Amplifier
EL 84 - RF Driver Amplifier
2x EL 84 - RF Output Amplifier
The transmitter had a simple FM stereo encoder, and the only major thing that it was missing was a PLL frequency synthesizer (and I'll build that last missing piece once I get the chance, just to finish the project off). Instead, it relied on a free running VCO that had to be readjusted from time to time. The output stage delivered up to 20W of RF power, and most central parts of the city could hear the program of a small music studio that me and my friends were running when we gathered up in the evening.Wimshurst Machine
A scene from Belgrade flea market, a place where you can sometimes find really odd items. This is an excerpt from a conversation between me and the Gypsy merchant:
- How much is this? (me pointing to an item lying in a pile of junk)
- 200 Dinars (around $3)
- Ooooh, come on (and turning away with a quite disappointed expression)
- All right, 100 Dinars! (I still keep acting uninterested)
- Ah, just look at it, two plastic discs on a wooden board! And half the parts are missing! 60 Dinars. (around $1).
- Oooh, now what kind of a deal is that!? All right, but if you tell me what the hell is that thing.
- Simple, it's a Wimshurst machine, invented in the 19th century. And you're telling me you don't know about it?.
- A what!? ... All right, get lost, you and your whm.... whatever machine!