Showing posts with label 5. Show all posts
Showing posts with label 5. Show all posts
Monday, November 17, 2014
Wave antenna 5 8 pro VKV FM
Wave antenna 5/8 consists of a vertical radiator which is fed at the base of the antenna. A suitable device of some sort should be added between the antenna and feedline if you want to eat with coax. Adding a coil in series with the antenna on the base is one of these methods are suitable.
So why would anyone use an antenna 5/8 wave if they have to go through all that extra work? After all, a ground plane antenna provides a good match. There are several answers. The first is GAIN. The computer shows that the antenna (mounted 1 foot above the ground) has a margin of about 1.5 dBd higher than a dipole (also installed 1 foot above the ground.)The second reason you might want to use the wave 5/8 vertical is to get a lower angle of radiation. Peak radiation angle A half-wave antenna is 20 degrees. You will find that the angle 5/8 wave antenna radiation is only 16 degrees so it is better dx antenna.
You may have noticed a pattern developing here. A quarter-wave ground plane antenna has a radiation pattern that produces the maximum gain at about 25 degrees and half-wave antenna drops to 20-degree angle, and wave antenna 5/8 further drops to 16 degrees angle. So why not just keep extending the antenna to one full wave? Well it would be nice if it worked, but unfortunately the wave patterns begin to create a very high angle of radiation waves exceed 5/8. So weve reached the maximum gain at this point and extend the antenna further reduce profits only where we want it (low angle).
Of course if you are interested in a very short jump, extend the antenna will produce a nice profit on the dipole.All the length of the antenna depends on various factors. Some of these factors are: height above ground, the diameter of the wire, nearby structures, the effects of other antennas in the area and even the conductivity of the soil.This page allows you to calculate the wavelength for the antenna 5/8. It uses the standard formula, 585 / f (178.308 / f for metric) MHz to calculate the length of the element. If you have experimented with 5/8 wave antenna before and know a better formula for your QTH, feel free to change the formula accordingly. This formula is for the antenna wire.
Of course if you build your antenna out of the tube, total length of the antenna will be shorter, for example I have found that 21.5 feet seems to provide maximum benefit to the frequency of 28.5 MHz when using a 1 "tube, and 22.5. Foot seems be the best long-wire at the same frequency. Since the formula to calculate the antenna to be about 2 feet shorter, be sure to experiment and maybe add a little for your final term.
Sunday, August 31, 2014
5 Volt power Supply
This is 5 volt power supply schema diagram.This schema regulates 5V.Input voltage is 6V to 12V.
Parts
# LM7805
# 100nF condensators
# 100uF condensator
# 10uF condensator
# N4002 diode
# LED
# 470 Ohm resistor
Sunday, October 6, 2013
Dual Polarity 5 Volt Converter Using LM2685
A symmetrical ±5V power supply is often needed for small, battery-operated operational amplifier projects and analogue circuits. An IC that can easily be used for this purpose is the National Semiconductor LM2685. It contains a switched-capacitor voltage doubler followed by a 5-V regulator. A voltage inverter integrated into the same IC, which also uses the switched-capacitor technique, runs from this output voltage. The external circuitry is limited to two pump capacitors and three electrolytic storage capacitors.
The IC can work with an input voltage between +2.85V and +6.5V, which makes it well suited for battery-operated equipment. The input voltage is first applied to a voltage doubler operating at 130kHz. The external capacitor for this is connected to pins 13 and 14. The output voltage of this doubler is filtered by capacitor C3, which is connected to pin 12. If the input voltage lies between +5.4 and +6.5V, the voltage doubler switches off and passes the input voltage directly through to the following +5V low-dropout regulator, which can deliver up to 50mA. C4 is used as the output filter capacitor.
All that is necessary to generate the –5-V output voltage is to invert the +5-V voltage. This is done by a clocked power-MOS circuit that first charges capacitor C2, which is connected between pins 8 and 9, and then reverses its polarity. This chopped voltage must be filtered by C5 at the output. The unregulated –5V output can supply up to 15mA. The LM 2865 voltage converter IC also has a chip-enable input (CE) and two control inputs, SDP (shut down positive) and SDN (shut down negative). If CE is set Low, the entire IC is switched off (shut down), and its current consumption drops to typically 6µA.
The CE input can thus be used to switch the connected circuit on or off, without having to disconnect the battery. The SDP and SDN inputs can be used to switch the VPSW and VNSW outputs, respectively. These two pins are connected to the voltage outputs via two low-resistance CMOS switches. This allows the negative output to be separately switched off, whereby the voltage inverter is also switched off. Switching off with SDP not only opens the output switch but also stops the oscillator.
There is thus no longer any input voltage for the –5V inverter, so the –5V output also drops out. The SDP and SDN inputs are set Low (<0.8v)>2.4V) for switching off the associated voltage(s). The positive output of the LM 2865 is short-circuit proof. However, a short circuit between the positive and negative outputs must always be avoided. The IC is protected against thermal destruction by an over-temperature monitor. It switches off automatically at a chip temperature of around 150C. The full type number of the IC is LM2685MTC. It comes in a TSSOP14 SMD package. National Semiconductor can be found on the Internet under www.national.com.
Continue reading...
The IC can work with an input voltage between +2.85V and +6.5V, which makes it well suited for battery-operated equipment. The input voltage is first applied to a voltage doubler operating at 130kHz. The external capacitor for this is connected to pins 13 and 14. The output voltage of this doubler is filtered by capacitor C3, which is connected to pin 12. If the input voltage lies between +5.4 and +6.5V, the voltage doubler switches off and passes the input voltage directly through to the following +5V low-dropout regulator, which can deliver up to 50mA. C4 is used as the output filter capacitor.
All that is necessary to generate the –5-V output voltage is to invert the +5-V voltage. This is done by a clocked power-MOS circuit that first charges capacitor C2, which is connected between pins 8 and 9, and then reverses its polarity. This chopped voltage must be filtered by C5 at the output. The unregulated –5V output can supply up to 15mA. The LM 2865 voltage converter IC also has a chip-enable input (CE) and two control inputs, SDP (shut down positive) and SDN (shut down negative). If CE is set Low, the entire IC is switched off (shut down), and its current consumption drops to typically 6µA.The CE input can thus be used to switch the connected circuit on or off, without having to disconnect the battery. The SDP and SDN inputs can be used to switch the VPSW and VNSW outputs, respectively. These two pins are connected to the voltage outputs via two low-resistance CMOS switches. This allows the negative output to be separately switched off, whereby the voltage inverter is also switched off. Switching off with SDP not only opens the output switch but also stops the oscillator.
There is thus no longer any input voltage for the –5V inverter, so the –5V output also drops out. The SDP and SDN inputs are set Low (<0.8v)>2.4V) for switching off the associated voltage(s). The positive output of the LM 2865 is short-circuit proof. However, a short circuit between the positive and negative outputs must always be avoided. The IC is protected against thermal destruction by an over-temperature monitor. It switches off automatically at a chip temperature of around 150C. The full type number of the IC is LM2685MTC. It comes in a TSSOP14 SMD package. National Semiconductor can be found on the Internet under www.national.com.
Thursday, October 3, 2013
Simple Cat 5 Network Tester
This circuit came from a need for a "quick and dirty" network tester that could be operated by one person. All the commercial units I tried required a person at the other end to check the remote LEDs, as the transmitters could not be made to cycle through the test continuously to allow one person to check both ends. It must be noted that this unit will only check for pair continuity, pair shorts, crossed wires, and shorts to other pairs. It will not test bandwidth, etc. Operation is fairly basic.
Half of the 4011 quad 2-input NAND gate is an RS flip-flop (IC1a, IC1b) which controls the other half, IC1c & IC1d, operating as a clock oscillator. You can either start and stop the oscillator running by pressing the Start and Stop switches or by virtue of diode D1 connected to pins 12 & 13, use the Stop switch to allow manual clocking of the 4017 counter. The 4017 drives one of eight LEDs and the lines to the RJ45 socket. An output "High" on the 4017 decides which line is under test, and if the circuit is complete, the test LEDs current is "sunk" by the 4017 and the LED will light.
If the corresponding test LED on the remote fails to light, then there is a short of that pair in the cable under test. If more than one LED lights, it indicates a short with another pair. A dark test LED on the transmitter indicates that pair is open circuit. "Start" starts the circuit cycling at a rate determined by the 470nF capacitor and 220kO resistor and "Stop/Step" stops cycling, steps through the lines, and when stepped so that no channel LEDs are alight, effectively switches the unit off with a standby drain current of less than a microamp.
Continue reading...
Half of the 4011 quad 2-input NAND gate is an RS flip-flop (IC1a, IC1b) which controls the other half, IC1c & IC1d, operating as a clock oscillator. You can either start and stop the oscillator running by pressing the Start and Stop switches or by virtue of diode D1 connected to pins 12 & 13, use the Stop switch to allow manual clocking of the 4017 counter. The 4017 drives one of eight LEDs and the lines to the RJ45 socket. An output "High" on the 4017 decides which line is under test, and if the circuit is complete, the test LEDs current is "sunk" by the 4017 and the LED will light.
If the corresponding test LED on the remote fails to light, then there is a short of that pair in the cable under test. If more than one LED lights, it indicates a short with another pair. A dark test LED on the transmitter indicates that pair is open circuit. "Start" starts the circuit cycling at a rate determined by the 470nF capacitor and 220kO resistor and "Stop/Step" stops cycling, steps through the lines, and when stepped so that no channel LEDs are alight, effectively switches the unit off with a standby drain current of less than a microamp.
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