This document describes the transmitter system supplied to Radio Glen for testing as designed and constructed by Henry.
The transmitter is supplied in prototype form and has the physical limitations of an instrument constructed using prototyping techniques. The transmitter has been designed to conform to the Radio Authority and Wireless Telegraphy requirements but the user must realise that this transmitter has not passed formal type approval tests. The operating station licensee and the technical manager bear the responsibilty of ensuring that the transmitter is not used in such a way as to cause interference to other wireless services or as to cause danger due to electrical shock or fire. Due to the increased power output capability of the transmitter it is especially essential that the signal distibution system is maintained in good condition and checked regularly.
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Technical Specification: Modulator Unit
Power: 240V mains
Audio Input: Stereo standard line level 0dbm 775mVrms on XLR sockets balanced input.
Indicators: Mains neon, 5V rail LED, 22V rail LED, crystal oven heater LED
Controls: Mains on/off rotary switch
Frequency Ref: Ovened crystal driving PLL frequency divider
Ouput frequency: Supplied as 1602kHz +/- 2Hz for University Radio Glen.
(now modified to 1287kHz)
RF output level: Approx 2Vpp with 80% modulated AM signal
Output connector: Female BNC
Case: Standard 19” rack mount ?U
Mod bandwidth: -3dB at 6kHz from carrier, -40dB at 9kHz as required by WT regs.
Modulation limiting: Will not exceed 100% modulation with transient +10dBm 1kHz tone burst.
5. Technical Specification: PA Unit
Power: 240V mains
Input: Variable 0.5 to 2Vpp with 80% modulated AM signal
Indicators: Mains neon, 30V rail LED, Unregulated supply LED.
Controls: Dual on/off for each section. Dual input attenuators for each section.
Ouput: 10W AM into 50 ohms from each section.
Input connectors: Female BNC
Output connectors: Female BNC
Input impedance: Approx 1kohm each section
Ouput Impedance: 50ohm
Output harmonics: 40dB down on the main carrier as required by WT regs
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