Voice Transmitter Circuit -TV Band 2

Voice Transmitter Circuit - 202 to 230 MHz

Parts List - Components Not Listed On The Schematic

D2 - D3 = 1N4005 (x2)     

Antenna: 13 " of small diameter stranded insulated wire.

L1 and L2 are identical, air wound, using # 22 magnet wire. 3 turns wound on the smooth end of a 1/8 drill bit. wind the turns on these two coils tight against each other.

Adjustable capacitor C1 is a 2 to 20 pf

Z1 is a 5.1 zener diode

Alignment of the unit after initial assembly and when the battery is connected. The device will come up at around 202 mhz, TV Band 2.

Turn your TV-2 band receiver on. To raise its frequency, spread the turns of L1 only. Once  you have set its frequency using either your receiver or a frequency counter, adjust C1 until maximum radiation is indicated on either a field strength meter or some form of bug sniffer. The device has a top end frequency of about 230 mhz with coil L1 spread "very wide."

 

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Voice Transmitter Circuit -TV Band 2
Every now and then I have been asked if I have ever engineered a transmitter circuit totally out of the FM or VHF band and into a unique frequency spectrum that can still be received. The answer is yes. Back in 1993 I had a special request for such a receiver. The request came from a Drug Task force in the Midwest. I put this transmitter circuit together for them. You can purchase portable FM receivers now that have the TV Bands 1 and 2 on them where the audio from those TV channels can be received. I engineered this Transmitter to operate in the upper TV band between 202 and 230 MHz. The component values that are missing in the schematic are listed below. Enjoy, John.