KitsRus 250mW FM Power Amplifier

Low Power VHF Final Amp
Assembling the KitsRus 250mW FM Power Amplifier • Home PageLow Power Radio Blog
I recently ordered and assembled this little broadband amp kit. My order arrived in good condition in about 10 days.

According to KitsRUs, "This project is a simple 2-transistor VHF power amplifier, with about 16dB gain, and requires no tuning or alignment procedures. Wideband techniques have been used in the design and the circuit is equipped with a "lowpass" filter to ensure good output spectral purity. The project has been designed for assembly on a single-sided printed circuit board. The circuit is specifically designed to amplify the output of 7mW to 10mW WBFM transmitters (wide band) to a final level of 70mW to 150mW, after the filter, at the low frequencies used in the FM band."

Here is the schematic:

Here is a link to the OEM Schematic and assembly instructions (sorry, no foil pattern)


This kit is based on the 400mW 100MHz RF Amplifier by Harry Lythall - SM0VPO as featured on his web site. The consumer kit comes from KitsRus in the near east, and I purchased it from Quasar Electronics, here:

My hat is off to Quasar, by the way, the first mail order firm that really, really didn't abuse my eamil address in some way! It's been about 4 months since I placed my order, and not a speck of spam of any kind. I enthusiastically support vendors like Quasar/QualityKits.

The kit included a PCB with solder mask and silk screen, making assembly easy and mistake-free. All the required parts for assembly were included, nicely packaged and clearly marked. Assembly instructions are clear, easy to follow and error free.

Assembly was simple and easy, starting with placing the components on the board as shown on the silk screen and then pulling the component lead through the board.  None of the components were particularly fragile or sensitive and assembly went very smoothly.


You might also like the CANCK108 - Universal FM Transmitter with Mic and Line Inputs (Solder Kit), $19.95

EDM 10 mW Stereo Transmitter pictured with the 250 mW Amplifier. This amplifier is an excellent companion to a low power transmitter in the 7mW to 10mW range like the EDM 10 pictured to the left  The 16 dB of signal boost is estimated to give a final signal level increase of 70mW-150mW in the relatively low frequencies of the FM BCB, more than enough for a low power home broadcast station.  With a well matched antenna the range could exceed 3,000 feet or over half a mile (1 mile=5,280 feet).  The full 250mW would likely be delivered at higher frequencies - 144 Mhz, etc.       


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