In any radio workshop, an RF decibel meter or power meter is an important instrument. Unfortunately, home-constructed ones are generally not sufficiently sensitive and/or are very temperature-dependent. These drawbacks are overcome by a device from Analog Devices which has recently become available: a low-cost DC–500 MHz, 92 dB logarithmic amplifier that enables an accurate, not too expensive to be constructed.
Here's a simple FM transmitter design. It uses pll circuit from Motorola MC145170. This PLL includes the prescaler and a serial standard bus called SPI. We advise to use the P2 version that fixes some init issues during the Power Up.
This RF remote control is useful to handle some electric device. If you want to control your garage door, the only way is to use some RF remote control. The transmitter-receiver circuit use few components and ordinary. It's easy to build it because you don't have to tune-up any coil or variable capacitor. The RF modules are fix to work in 418MHz area.
Here's a broadband FM RF amplifier using 2SC1971 VHF power transistor. The RF Amplifier PCB layout designed for FM broadband 88-108 MHz using microstripline technique. This 8W RF amplifier circuit provides an appropriate power boost with an input of 500 mW.
