PC Electronics TX70-5 70 User Manual

P. C. Electronics 2522 Paxson Lane Arcadia CA 91007-8537 USA ©2009
Tel: 1-626-447-4565 m-th 8am-5:30pm pst (UTC - 8) Tom (W6ORG) & Mary Ann (WB6YSS)
Web site: http://www.hamtv.com Email: ATVinfo @ hamtv.com
TX70-5 70 CM ATV TRANSMITTER
USERS MANUAL
The TX70-5 transmitter is designed to provide over 0-5 Watt continuous duty peak envelope
power (sync tip) of video modulated RF in the 70 CM (420-450 MHz) amateur band. Any licensed
Technician class or higher Radio Amateur may operate this transmitter in accordance with 47 CFR part
97 of the FCC Rules and Regulations. The TX70-5 accepts U.S.A. standard composite video (1 volt pk-
pk) from any source such as color or black and white TV cameras or camcorders, VCRs, or computers
for transmission. Audio from these sources or a low impedance dynamic mic is also transmitted on the
4.5 MHz sound subcarrier. Transmit / receive power and antenna switching is provided for the compan-
ion TVC-4S downconverter.
PLEASE read through this manual before plugging in an cables and attempting operation. Each
connector and control is described here to enable your proper hookup and operation. Also the unique
video practices associated with ATV and the 70 CM band are described.
1
W6ORG ©2009

PC Electronics TX70-5 70 Specifications

General

Brand	PC Electronics
Model	TX70-5 70
Category	Transmitter
Language	English

Summary

TX70-5 70 CM ATV Transmitter Overview

Rear Panel Connections

Power Input Jack

Details the 4-pin plug, voltage requirements (+12 to +14 Vdc), and current draw (500 MA).

Internal Fuse Protection

Describes the 1 Amp fuse and troubleshooting for repeated blowing, including zener diode checks.

Video Monitor Output

Provides composite video for monitoring during receive periods; connection options via RCA plug.

70 CM Antenna Connection

Specifies the UG21 type N plug for 50 Ohm coax and recommends low-loss cable types.

Downconverter Output

Connects to the antenna input of a 70 CM ATV downconverter via BNC jack.

Front Panel Controls and Inputs

Video Input Connector

Accepts standard NTSC composite video (1 volt pk-pk) from various sources via RCA plug.

Audio and Control Inputs

Line Audio Input and Gain

Covers high-level audio input and its gain control for mixing with video.

Microphone Input and Gain

Details low-impedance mic input and its gain control for voice-over commentary.

Transmit Control Switches

Explains PTL and XMIT/REC switch functions for transmit/receive control.

Power On Switch

Activates the +12 to 14 Vdc power supply to the TX70-5 unit.

Operating Notes and Adjustments

Internal Adjustments

Discusses setting output power with a wattmeter and ensuring adequate convection cooling.

ATV Operating Practices

Explains unique ATV operational considerations, coordination frequencies, and full duplex audio.

Antenna Polarization

Discusses polarization choices (horizontal vs. vertical) and their impact on signal reception.