The 'Pantek' ---The worst 3-watt FM transmitter ever built
."Professional Transmitter, Varicap controlled stability" said the advert for this piece of self oscillating junk!
Here is one of the worst FM broadcasting transmitter
kits I have ever come across, probably THE worst. The thing below has
sold thousands since it came along in the 1980's. You may have seen
one, with the name'PANTEK' stamped on it. They sold for around £20-00
and looked like value for money.
Although rated at 3 watts rf power output, you would rarely see
more than half a watt. The worst thing was that so many spurious frequencies
were present, you didn't really know which was the main signal. The
designer of this
The above circuit diagram shows the audio pre-amplifier on the left, a conventional dc coupled cascade 2 transistor amplifier. The 'low' input would work with a microphone and the 'high' input was for line level input, i.e. a cassette player. The transmitter section is to the right and this shows the cross coupling from outputs to inputs with C8 and C9. T3 and T4 would get very hot and often failed, mercifully halting the transmission.
This picture above shows the printed circuit board. Note there is no groundplane!!!!
And this it, above, the component layout of the infamous 'Pantek' 3-watt fm transmitter! It was a small transmitter pcb, measuring just 121mm x 44mm. It was sold as a kit to build yourself and some people actually claim to have got the thing working successfully. If you want to build one, the parts list is provided below!
Resistor list: Capacitor list: Semiconductors: Specs
R1 100K C1 22uF 16V D1 4001 Power supply: 12-15V
R2 100K C2 22uF 16V T1 BC549 Current: 0.5A R3 47K C3 22uF 16V T2 BC549 Frequency: 80-108Mhz R4 220K C4 0.047uF T3 2N3553 Input: 10mV / 1V R5 1K C5 1nF T4 2N3553 Arial impedance: 75 Ohm R6 47K C6 10pF D2 VCD ITT BB139
R7 15K C7 27pF R8 2.2K C8 27pF T3/T4 need heatsinks R9 10K C9 0.047uF
R10 100K C10 22uF 16V R11 4.7K TR1 2-18pF, red R12 10K TR2 5-65pF, yellow R13 4.7K P 10K