0-500Mhz μετρητής σήματος RF για το PC με το AD8307

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AD8307 USB 0-500MHz RF Power Meter Component List: 1x PIC18F2455 / PIC18F2550 Programmed Microcontroller 1x AD8307 8-DIP RF Power Meter IC 1x USB IO Board PCB 1x USB Type B Connector 1x 20MHz Crystal Resonator 1x 470K Resistor (yellow purple yellow gold) 2x 10K Resistor (brown black orange gold) 2x 100 Resistor (brown black brown gold) 1x 470nF Ceramic Capacitor 5x 100nF Ceramic Capacitor

Technical Specifications: Measures transmitter RF Power from 1nW to 2W / -66.6dBm - 30dBm Auto-range RF Wattage Measurement: W, mW, uW and nW Frequency Input: 0-500MHz Self-powered by USB port Can measure higher RF power with addition of simple 10-40dBm resistor attenuator

About AD8307 USB 0-500MHz RF Power Meter

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Measurement of transmitter output RF power has never been easier and more precise. AD8307 USB 0-500MHz RF Power Meter allows to measure the power of transmitters from 1nW to 2W. Output is displayed in dBm, Watts (nW, uW, mW and W range) as well as input voltage. USB RF Power Meter is based on popular AD8307 watt meter IC and PIC18F2550 microcontroller. Instead of using LCD display module the meter connects to a PC via USB port and displays measurements on a computer via USB RF Power Meter software. The software settings can be changed to use 10-50dBm attenuator and thus allowing to measure higher RF power than 2W.

Digital AD8307 RF Power Meter Probe

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AD8307 RF Power Meter Probe can be mounted on a small 1.5cm x 3cm pre-drilled PCB board. To measure output RF power of transmitter connect AD8307 probe input directly to the output of your transmitter (antenna output). AD8307 probe should be connected to USB IO Board by using three wire cable. The three wires provide power for the probe that is drawn from USB port through USB IO Board, ground wire and output that connects to PIC18F2550's PIN2 (A0). For best results AD8307 probe may be mounted in standard two way antenna splitter which could be obtained in a local hardware store. This will provide a nice ground shielding and antenna connector already in place.

USB IO Board PCB

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USB IO Board is used to sample voltage from AD8307 chip and pass the information in a digital format to a PC via USB port. The board consists of very few components; mainly PIC18F2550 microcontroller, standard USB Type B connector, breadboard compatibille PCB, 20MHz crystal resonator, two capacitors and two resistors.

Installing USB IO Board Drivers

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Before USB IO Board can be used the following drivers must be installed. 1) Download USB IO Board drivers and unzip it. 2) Connect USB IO Board and to your computer using USB cable. 3) Windows will ask you if you want to install a driver. Point it to drivers you unzipped. Windows 2000 / XP Under Windows 2000 or XP you will be prompted twice to install two drivers. On the first prompt please browse and point to MCHPUSB driver folder. On the second prompt please browse and point to USB CDC driver folder. Windows 7 / VISTA Under Windows 7 or VISTA you might be only prompted once to install USB CDC driver if MCHPUSB driver is already installed. 4) After the drivers are installed go to the Device Manager (right click on My Computer and click Properties->Hardware->Device Manager), and look under the Ports (COM & LPT) section, and you should see a new serial port there. Note the COM port number.

AD8307 USB 0-500MHz RF Power Meter Kit

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We are distributing Power Meter Kit at Electronics-DIY store. The software and drivers are included with the kit. Please see the link for more information.

Ενισχυτής FM 5 watts

5 Watt FM Amplifier This design is a 2 stage amplifier that has about 17db of gain, suitable for an input of 50 to 100 MW. Its basically a Veronica 5 watt vco transmitter, without the vco. The transistors are a 2N4427 and a MRF237. Output power is 2.5 to 5 watts, depending on input drive and dc voltage. At 13.7 vdc with 50 MW of drive, the output was 2.5 watts. The maximum dc voltage recommended is about 15-16 volts. The unit is constructed with copper clad board, a large piece is used as the construction surface and is mounted into a case. Other board material is cut into small pads, then glued to the construction surface for part connections. A heatsink is needed for the both transistors, a small "top hat" style will work for TR1 but TR2 requires a larger heatsink thats attached to the case. This is made from aluminum L stock, a 3/8" hole and a slot is made for TR2 to fit snuggly in. Up to 7-8 watts output is possible with this amp, but for continious duty only 5 watts maximum output is recommended. A fan is required and it is mouted on the case lid, with holes drilled for ventilation. The chokes H1, H2 and H3 are 5 turns of 30 awg wire on a ferite bead and choke H4 is a 330 ohm 1/2 watt resistor with 14 turns of 30 awg with a ferite bead on each end. Ferite beads need to be of type 43 material. The coils L1, L2 and L3 are made of 18 awg tinned wire. A 1.5 amp 3ag fuse is part of the dc power cord assembly. I used BNC coax connectors for input and output, however SO-239 or F type connectors would be fine too. Tune up and use: In order to make the amplifier operate properly, it needs to be tuned. To start, set all the trimmer capacitors to middle position, connect the rf out to a wattmeter/dummy antenna, apply power and drive from the exciter then tune for maximum output. Limit your drive to 100 MW maximum. If you can measure the amplifier transistor's current, then adjust for minimum current at maximum rf out. This unit has no swr protection and requires a 50 ohm antenna, do not operate the amplifier without a proper load.

Ενισχυτής rf με ισχύ 1 watt

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Parts: Q1 Transistor: 2N5109, MRF227, 2N4427, 2N3866

Specifications: Voltage Supply: 12 - 15V

Description

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This is a universal 1 Watt RF class C amplifier that is ideally suited for low power FM transmitters. Input should be at least 100mW to achieve 1W output. It is recommended to enclose the amplifier in a metal case.

Απλό όργανο μέτρησης στασίμων

This article describes a simple SWR meter that I have built using readily available parts. Note that no attempt has been made to ensure accurate power readings, as I am usually aware of the approximate power level I'm running. I simply wanted a circuit that would fit in a small enclosure, and give me an indication of 'minimum' swr. This circuit does the trick. It is based on the ever popular WM-1 made by Oak Hills research, with a few changes.
I built this circuit up, as I do most of my homebrew stuff, dead-bug style. A little planning results in a compact, and symmetrical layout. (symmetry is important for the section containing L1/L2).
Note that T1 and T2 are somewhat unusual. Start with a FT50-61 core. Wrap 24 turns of enameled wire on it (size not critical as long as it fits). Spread the turns out to cover most of the core. Next take a 1 inch long piece of RG-58/U and strip about 1/8 inch of the jacket off both ends. Remove the braid covering the dielectric on one end, and twist the braid on the other end into a pigtail. Slip this prepared cable through the prepared toroid, and connect one end of the enameled winding, as well as the braid to ground. The other end of the enameled winding connects to the anode of D1 as shown. One side of the center conductor of the coax attaches to the input connector J1, while the other end goes to the output connector, J2.
Take another FT50-61 core, and create another assembly as above. Connect one end of this core's enameled winding to the output connector, while the opposite end goes to ground. One end of this core's length of coax attaches to the anode of D1, while the other end connects to the anode of D2. Don't forget to ground the pigtail of this core's coax braid. This whole process is easier to do than to describe!
The purpose of the lengths of coax, is to provide a single turn primary (a wire passing through a toroid acts as a single turn) while the shield grounded at one end only, acts as a Faraday shield, (see any older ARRL Handbook for a description of this forgotten technique) which reduces the 'capacitive' coupling between windings.
I used an LM324 IC as it can be had at Radio Shack and runs off a single supply. The values shown in this part of the circuit are for a 200uA meter movement I happened to have. A different meter may require changing these values somewhat. The rest of the parts can be had from Radio Shack or Dan's Small Parts.
To use, connect your TX to J1, a 50 Ohm load to J2, set the switch to 'forward' and adjust R for approximately full scale deflection on key down. Switching to 'reflected' should show very little or no deflection. If not, check your wiring.
This circuit should work with QRP rigs in the HF bands, although I have made no attempt to try it on other than 20 and 40.

Ένα μίνι tuner για τα βραχέα

Κεραία "L" για τα 160 μέτρα

One of the problems with short, low antenna's on 160 metres is that their input impedance is very low, usually on the order of a few ohms.
A clever trick to overcome this is to intentionally make the antenna to long. This will make the resistance increase, but also add inductive impedance.
Simply add a series variable capacitor to tune it out.




I use an "L" shaped antenna on 160 and have had very good results. It is a total of 165 feet long and shows an impedance of 50 ohms+j88. It is not necessary to know any maths or have an expensive impedance bridge to use this antenna. Just make the capacitance variable and you'll be in the ballpark.
Adjust with a SWR meter, cut and try adding or subtracting the length. Its not critical at all. The horizontal part can be routed just about anywhere. Try to make the vertical part as high as possible.
For the ground Iv'e tied everthing together, furnace ducts, ground rods, house ground, dogs chain (just kidding !), and radial system, with braid from RG8/U.
Does it work?, You bet!!
49 States on CW including Hawaii, and just about that many on ssb with only 100w output.
ALSO..... I feed it with a tuner as a long wire and with QRP I've worked both coasts. On the higher bands the capacitor's impedance is so low it makes practically no difference if you leave in or take it out.

Πώς να κατασκευάσετε ένα μικρού μήκους δίπολο για τα 160 μέτρα