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Category: Electronic UpDownloads in English
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 ANTENNA FUNDAMENTALS | | Description: | In this chapter, the basic concept of an antenna is provided and its working is explained. Next, some critical performance parameters of antennas are discussed. Finally, some common types of antennas are introduced.
Antennas are metallic structures designed for radiating and receiving electromagnetic energy. An antenna acts as a transitional structure between the guiding device (e.g. waveguide, transmission line) and the free space. The official IEEE definition of an antenna as given by
Stutzman and Thiele [4] follows the concept:
That part of a transmitting or receiving system
that is designed to radiate or receive electromagnetic waves. | | | Filesize: | 0 Bytes | | Added on: | 21-Dec-2008 | | Downloads: | 493 | | Category: | Electronic UpDownloads in English | | Details |
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| 1.5-W STEREO AUDIO POWER AMPLIFIER | | Description: | High Power with PC Power Supply
– 1.5 W/Ch at 5 V
– 600 mW/Ch at 3 V
Ultra-Low Distortion
< 0.05% THD+N at 1.5 W and 4-W Load
Bridge-Tied Load (BTL) or Single Ended
(SE) Modes
Stereo Input MUX
Surface-Mount Power Package
24-Pin TSSOP PowerPADE
Shutdown Control . . . IDD < 10 mA | | | Filesize: | 0 Bytes | | Added on: | 16-May-2006 | | Downloads: | 439 | | Category: | Electronic UpDownloads in English | | Homepage | Details |
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| 20 meters CW QRP Transceiver | | Description: | Simple QRP CW Transceiver for the 20 meters
DATA:
RF Power: near 1 watt at 24 V.
Range of Feeding Voltage: 18- 24 Volts
Antenna impedance: 75 Ohms (can be any
desirable)
Quartz Stabilization Frequency.
Shift TX/RX: 400… 700 Hz.
VXO: 3… 6 kHz (depends on used quartz) | | | Filesize: | 0 Bytes | | Added on: | 21-Dec-2008 | | Downloads: | 410 | | Category: | Electronic UpDownloads in English | | Details |
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| Remote Synthesised VFO | | Description: | A Remote Synthesised VFO for the HW9 by Stewart Rolfe / GWØETF
This project provided an opportunity to put to good use a long held interest in Programmable Interface Controllers (PICs) and an urge to play with the new Direct Digital Synthesiser chips which had just started appearing in the amateur radio press in such articles as G3XJP’s excellent Pic’n Mix in RadCom1. The
following describes an exercise in self education first and foremost, but one which has been applied in practice to cure some basic problems in an otherwise fine QRP transceiver. Though aimed at one specific radio it is hoped that the description will be of more general interest and could be easily adapted to other
situations. Most of the technical content is a compilation of previously published ideas and articles with a
small amount of original material mainly connected with the need to adapt to the specific case of the HW9.
All material used is fully acknowledged, and reference to the original sources will provide a fuller description
of what is included here. | | | Filesize: | 300 Bytes | | Added on: | 09-Jan-2010 | | Downloads: | 405 | | Category: | Electronic UpDownloads in English | | Details |
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| Direct Digital VFO | | Description: | An Advanced Direct-Digital VFO
The author used an Analog Devices AD9951 DDS IC in a new VFO design.
This article describes a hardware design that features the Analog Devices AD9951. A 14-bit D/A converter at the output, and
a much higher rated clock speed than the 98xx family allows a frequency-dependent SFDR in excess of 70 dB, and approaching
80 dB with a 400 MHz internal clock frequency. It puts the latest technology on a four layer, 3 inch circuit board, and can be used as
a stand-alone VFO or as part of a multi-loop frequency synthesizer. There are two stages of RF filtering included in the design: the first
between the 9951 DDS and the output buffer amplifier, and the second after the buffer, at the board output. A significant capability
for software expansion exists, as only about 2 KB of program memory (out of an available 12 KB) is presently used. As in previous
designs, tuning is accomplished with a shaft encoder. An inexpensive LCD provides a frequency readout. | | | Filesize: | 300 Bytes | | Added on: | 09-Jan-2010 | | Downloads: | 393 | | Category: | Electronic UpDownloads in English | | Details |
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| DIGITAL VFO | | Description: | The DDS digital VFO gives you the full control of your receiver and transmitter, with performance like modern commercial transceivers. The IF frequency value can be programmed (i.e. 5.645 KHz for Drake, 4915 KHz for Elecraft K1 or K2, xx MHz for many other commercial or homebrew transceivers) You
can set it for zero beat in your receiver, for exact calibration if the carrier oscillator of your receiver is not correct.
It is possible to set-up different IF offsets for RX and TX, as it maybe the case some homebrew transceivers, where the TX IF is different from the RX IF. The specific set-up is reported in the following description. To change the IF RX frequency value, simply tune the frequency required, i.e. 5645.125,
and press keys SPL and RIT for 2 seconds, at the same time.
Now the new IF value for the RX is stored in memory. (the VFO output frequency has a positive offset frequency equal to “ Frequency displayed + IF” ) To change the IF TX frequency value, simply tune the frequency required, i.e. 5.645.125,
and press keys VFO and SPL for 2 seconds, at the same time.
The new IF value for the TX is stored in memory. (the VFO output frequency has a positive offset frequency equal to “ Frequency displayed + IF”) To have the TX functionality is necessary to put a GND to PIC I/O pin 15 ( PORT C4). You can use the PTT mike line of your transceiver for this control. | | | Filesize: | 600 Bytes | | Added on: | 09-Jan-2010 | | Downloads: | 386 | | Category: | Electronic UpDownloads in English | | Details |
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| PIC Programmer and Test-Demonstration Board | | Description: | 1 Introduction
2 Hardware Description.
2.1 PIC programmer
2.2 Project/Demonstration
2.2.1 PIC system clock (crystal).
2.2.2 LEDs
2.2.3 Pushbuttons
2.2.4 LCD.
2.2.5 Rotary Encoder
2.2.6 Speaker .
2.2.7 Signal generation with the NJQRP DDS Daughtercard
2.2.8 Signal Conditioner
2.2.9 CW paddle Input via a Stereo Jack
2.2.10 Transmitter Keying via a Stereo Jack.
2.2.11 Frequency Counter
2.2.12 How to Drive a Relay from a PIC
3 PIC-EL Assembly
3.1 Parts Identification
3.2 Test Points
3.3 Assembly
3.4 Final installation and Basic PIC-EL Test
4 PIC-EL Computer Interface
4.1.1 Installing FPP
4.1.2 Installing FPPA
4.1.3 Using FPP / FPPA
5 PIC-EL Diagnostic Program
5.1 Test LEDs
5.2 Test Pushbuttons
5.3 Test Speaker
5.4 Test Encoder
5.5 Test Paddles
5.6 Test Transmitter Keying
5.7 Test DDS-30
5.8 Test DDS-60
6 Elmer-160 Lessons | | | Filesize: | 900 Bytes | | Added on: | 09-Jan-2010 | | Downloads: | 385 | | Category: | Electronic UpDownloads in English | | Details |
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