Monday, March 18, 2013

VHF AM converter circuit

There are many people who want to listen whats going on in VHF 108 – 132 MHz. This vhf am converter converts a band between 106 and 150 MHz, so you can listen even 2m radio amateurs (144Mhz).
Thisvhf am converteris build with anvhf amplifier, one mixer and oscillator. After the input signal is amplified with T1 it is applied to a mosfet mixer and combined with the quartz oscillator output.
The tuning is between 6 and 30 MHz. Thequartz frequencyis fx = fi-fo where fo is output frequency and fi is input frequency.

VHF-AM converter circuit diagram

vhf-am-converter
Components:
L1 = 7 turns / 3 turn from ground
L2 = L3 = 3 turns
L4 = 4 turns / 1 turn from ground
L1 … L4 = CuEm SWG 20
L6a = 4 tunrs / SVG 36
L6b = 4 turns / SWG 24
L6a and L6b are build togheter on ferrite 3 x 6 mm
L5 = L7 = 0.82 uH
L8 = 1 uH
Quartz crystal = 100 …. 120 MHz overtone armonic 5

VHF-AM converter pcb layout

vhf-am-converter-pcb
Reprinted the url of this article at http://www.hqew.net/circuit-diagram/VHF-AM-converter-circuit_8635.html

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