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vhf transmitter

3 years ago 1503
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Description

BBG - Crystal Controlled FM Transmitter The Original Circuits Below Were Built and Sold - In The Thousands To Law Enforcement. Their Original Research and Development Cost , By Today's Standards, Would Total - Well Over A Million Dollars.

FM Transmitter Circuit BBG (C) 2012 radio-circuits .com Radio-Circuits.Coml TP1 Transmitter5VT TransmitterDPT Transmitter 150xt TransmitterXMT TransmitterAB1 Transmitter WB1 Transmitter The BBG Transmitter transmits a Whopping - full 1/2 Watt - (Better Than 500MW) of voice modulated FM Narrowband Frequency Modulation. It is normally used by undercover Agents ( Concealed) as a "Body Bug" ) that has no drift, unlike an adjustable FM wideband transmitter. It transmits both sides of the conversation for up to 2 miles away - and is received on a regular scanner in the VHF frequency range of around 150 to 160 Mhz. BBG Transmitter © 2011 By John S. Wilson Jr. [email protected] Parts List: Circuit # BBG - 1/2 Watt Body Bug - Xtal Controlled

Resistors: 1/4 Watt

R1 = 10K R2 = 1 MEG R3 = 22K R4 = 1 MEG R5 = 22K R6 = 100 Ohm R7 = 10K R8 = 100K R9 = 10K R10 = 150 Ohm R11 = 100K R12 = 10 Ohm R13 = 150 Ohm ( 1/2 Watt Resistor On This One ) R14 = 2.2K R15 = 10 Ohm ( 1/2 Watt Resistor On This One ) R16 = 3.3K R17 = 47 Ohm ( 1/2 Watt Resistor On This One )

Capacitors: - Disc Or Electrolytic ( Electrolytic Shown with +/- ) All Low Voltage C1 = .02 ( Two .01s in Parallel ) C2 = .001 C3 = .01 C4 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C5 = 10 pf C6 = 100 pf C7 = 100 pf C8 = .01 C9 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C10 = .01 C11 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C12 = .01 C13 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C14 = .001 C15 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C16 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C17 = .001 C18 = 4 to 20 Pf Trimmer ( Adjustable ) Small Surface Mount Type C19 = .01 ( SPECIAL CAPACITOR ) There is A Capacitor Connected across R13 that is not shown in the schematic: This cap is a standard .01 Disc

Transistors:

Q1 and Q2 = PN918 NPN - Digi-key Electronics Q3 = 2N3866 NPN - Digi-key Electronics Q4 = PN2222 NPN - Digi-key Electronics Q5 and Q6 = 2N3866 NPN - Digi-key Electronics

VR: NTE-613 Varactor Diode or a suitable replacement like the Digi-Key Electronics MV2107

BATTERY - 9V

ON/OFF Switch: Any, On / Off Switch Will Do - connecting the + side of the 9 volt battery to the circuit M1: Small Electret Microphone Element - Digikey Electronics

L1: 21 Turns of # 30 Magnet Wire Wound tight on a Digi-key Electronics 3368K-ND Fiber Washer. The Inductance Of This Coil Is .150 uH L2 and L3: 14 Turns of # 24 Magnet Wire Wound tight on a Mouser or Digi-key Electronics 3368K-ND Fiber Washer. The Inductance Of This Coil Is .07 uH

Antenna: 18 1/2 Inches of small flexible stranded wire

XT: ( CRYSTAL ) I usually build this circuit to operate between 150 to 165 Mhz. The Crystals I use Are The Digi-Key Electronics Barrel Crystals CA-301 Type which cost a couple of bucks per crystal. This circuit uses a X5 Multiplier and then a X2 Multiplier In the Final.

Example: If I use a 15 Mhz Barrel Crystal, the frequency at Q4s output is: Xtal X 5 Or: 75 Mhz into Q5. Q5 Multiplies 75 Mhz X 2 for an end frequency out of the final Q6 ( Desired Output Frequency ) of 150.00 Mhz.

Virtually any Fundamental Crystal between 14 and 17 Mhz will output a frequency of between 140 to 170 Mhz, if the crystal has a load capacitance of around 18 pf. If you wish to build this transmitter on A custom frequency simply use the X5 X2 formula above and order a custom cut crystal specifying an 18 pf CL.

Example: My Customer Desires this transmitter to function at an output frequency of: 158.250 Mhz? ( 1 ) Divide 158.250 times 2. This Equals 79.125 ( 2 ) Divide 79.125 times 5. This Equals 15.825 I would order the crystal at a Fundamental frequency of 15.825 Mhz, tolerance of .001% and a Crystal Load Capacitance of 18 pf. When I tune my transmitter, my output transmit frequency would be: 158.250 Mhz.

Documents

Sheet_1

VHF

Antenna_Mini-Whip_PCB_(TH):_Main_module

VHFv1

pcb

NEW_PCB

PCB

www

WW

XVR

BOM

ID Name Designator Footprint Quantity Manufacturer Part Mounted
1 ELECTRET M1 9.7ELECTRET 1 ? Yes
2 10KΩ R1,R7 AXIAL-0.4 2 ? Yes
3 .02UF C1 RAD-0.1 1 ? Yes
4 .001UF C2,C14,C17 RAD-0.1 3 ? Yes
5 1MΩ R2,R4 AXIAL-0.4 2 ? Yes
6 PN918 Q1,Q2 TO-92A 2 ? Yes
7 22KΩ R3 AXIAL-0.4 1 ? Yes
8 .01UF C3,C8,C,C10,C12,C19 RAD-0.1 6 ? Yes
9 22K R5 AXIAL-0.4 1 ? Yes
10 100Ω R6 AXIAL-0.4 1 ? Yes
11 100kΩ R8,R11 AXIAL-0.4 2 ? Yes
12 20P C4,C9,C11,C15,C16,C18 JML06-1-30P 6 JML06-1-30P Yes
13 12MHZ X1 OSC-49S-1 1 X49SD12MSD2SC Yes
14 10P C5 RAD-0.1 1 ? Yes
15 2N3866 Q3,Q5,Q6 TO-5 3 ? Yes
16 10kΩ R9 AXIAL-0.4 1 ? Yes
17 150kΩ R10 AXIAL-0.4 1 ? Yes
18 100P C6,C7 RAD-0.1 2 ? Yes
19 PN2222A Q4 TO-92A 1 ? Yes
20 150Ω R13 AXIAL-0.4 1 ? Yes
21 NTE-613 D1 DIODE_DO-201AD_HORIZONTAL_RM15 1 6A2-T Yes
22 1m L1,L2,L3 AXIAL-0.6 3 ? Yes
23 10Ω R12,R15 AXIAL-0.4 2 ? Yes
24 30P C13 JML06-1-30P 1 JML06-1-30P Yes
25 47Ω R17 AXIAL-0.4 1 ? Yes
26 2.2KΩ R14 AXIAL-0.4 1 ? Yes
27 3.3KΩ R16 AXIAL-0.4 1 ? Yes

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