RF projects

Make your own monopole antenna

This guide show you how to make two designs of monopole antenna for 900 and 1300MHz video transmitters because the antenna that comes with the 900 and 1300MHz video transmitters usually aren?t any good. In fact they are quite inefficient and due to bad design and build tolerances of certain crucial parts. You can however quite easily improve the efficiency and thus the range of these systems by using a tuned antenna. [more]

Posted in : Audio and Video | RF projects

DiSEqC-Tester

DiSEqC-Tester allows to test DiSEqC-Switches that uses 1.0 or 1.1 protocols. (DiSEqC-Switches with 2.0 and 2.1 protocol have backwards compatibility with 1.0 & 1.1 respectively and also may be tested). The device every second sends command “Switch next port”. [more]

Posted in : AVR projects | Measurement projects | RF projects

Five by Twenty

5 tubes SSB QRP Transceiver for 20m Ham band
Five by Twenty : A 5 tubes SSB QRP Transceiver for 20m Ham band.It is a true SSB transceiver built around just 5 vacuum tubes, with no transistors nor ICs. Superhet receiver with AGC and S-meter drives a loudspeaker, 5W transmitter. Very stable VXO uses CB crystals to cover 20m Ham band.[more]

Posted in : RF projects | USB projects

40W broadband VHF RF Power Amplifier

This design use to boost the output power of low power FM broadcast band exciters, a number of these are available commercially, both as kits and ready made. The amplifier design is based on the recently introduced (1998) Motorola MRF171A MOSFET.The initial feasibility was performed using a linear RF and microwave simulation package, specifically Supercompact. [more]

Posted in : RF projects

250 mW RF modem

Trax writes:
Here is my home-built, cloth iron soldered, range extender for CC1101 (included onboard) RF transceiver chip from Texas Instruments. You could say that it is a CC1101+CC2591, but for 868/920MHz band. I used MAX2233 RF amplifier from Maxim-IC. It can deliver up to +24dBm (250mW) of RF amplification with +10dBm of input.You can download the project files at the bottom of this page by clicking on red “download” button.
[more]

Posted in : RF projects