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.
Click here to download the full size of the above Circuit.
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
This sheet shows the frequency synthesiser and modulator. The 74HC4060 uses a cheap 4.608MHz crystal to develop the 9kHz reference required for the VCO. The internationally agreed channel spacing in Europe...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: