Audio/Video Modulator – Valleman Kit

Sun, 16 Oct 2016 07:52:07 +0000

If it is desired to connect a video signal originating from a camera or other video source to a normal TV set, you will need this modulator. The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV antenna input. In certain countries (find out from your national telecommunications authority) it is permitted to use this modulator as a mini-transmitter by connecting a small antenna to it. With this facility it is possible to receive the signal from the video recorder or camera elsewhere within your home (range 30m, 98′ approx.). The kit comes complete with housing and antenna connector.

Specifications :
Input: audio and video.
Output: UHF channel 21 (450 – 500MHz adjustable).
Power supply: 12 to 15VDC / 100mA.
Dimensions: 70 x 104 x 30mm (2.8″ x 4.1″ x 1.2″).

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Audio/Video to UHF TV Signal Converter (Modulator)

Wed, 27 Jul 2011 13:18:33 +0000

Audio-video modulator circuit. Convert audio video signal to UHF TV signal

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This is the circuit diagram of audio/video modulator. The circuit will convert an audio and video signal into a UHF TV signal. It’s desired to connect a video signal originating from a camera or other video source to a normal TV set. The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV antenna input.

Audio/Video to UHF TV Signal – Parts List

R1 : 47
R2 : 100
R3 : 560
R4 : 1K
R5 : 1K
R6 : 1K
R7 : 10K
R8 : 1K5
R9 : 1K5
R10 : 1K5
R11 : 2K7
R12 : 2K7
R13 : 2K7
R14 : 5K6
R15 : 270K
RV1 : 50K (47K)
RV2 : 1K
ZD1 : 11V
ZD2 : 6V2

C1 : 3pF
C2 : 3pF
C3 : 3pF
C4 : 1pF
C5 : 3pF
C6 : 10pF
C7 : 15pF
C8 : 22pF
C9 : 33pF
C10 : 56pF
C11 : 100pF
C12 : 100pF
C13 : 180pF
C14 : 470pF
C15 : 1nF
C16 : 1nF
C17 : 1nF
C18 : 1nF
C19 : 1nF

C20 : 4?7
C21 : 4?7
C22 : 10?F
C23 : 10?F
C24 : 220?F
CV1 : 5pF
T1 : BC547B
T2 : MPSH10
T3 : MPSH10
T4 : BFR90
L4 : 10,7MHz
L5 : 10?H
LD1 : Red

High Frequency Inductor Windings
This is how to make high frequency inductors for L1, L2 and L3:

Cut 3 lengths of the 0.6mm wire supplied to the exact length.
Scrape the enamel off the ends of each length of wire with a sharp knife for about 5 mm and tin the ends.
Make up the windings on a gimlet of 3.5mm diameter.

high frequency inductor windings

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Download the application note of Audio/Video to UHF TV signal converter: