Michel P Website
15W MOSFET FM AMPLIFIER

Description (In course of drafting)

synthèse rapide du RDS

This new FM Power amplifier is based on the 6W design described on this website.
Same pcb dimensions, same technology.

Two stages are needed to get 15W output power with only 2.5mW from the input.
The first stage is biased in class A (BFG135), the second one in class AB (RD15HVF1).
We've modified the BFG135 RF design in order to get 250mW output power level to drive properly the RD15HVF1 transistor.
By the way, we expect this amplifier to deliver 15W output power with this RF modification.

We've also changed the low pass filter design to improve the rejection of the second harmonic.

All the impedance networks (Input & Output) have been determined by using the softwares: Mimp.EXE & Genesys.

The measurements and the RF specifications are available through the link below.

 

Parameter

Value

Power Supply

14V

Efficiency

> 55%

Frequency Range

87.5 MHz to 108 MHz

Input power (Typ.)

4 dBm or 2.5mW

Output power (Typ.)

41.7 dBm or 15W

Gain (Min)

38 dB

Ripple Power

42 dBm +/-0.2dB

Harmonic filtering

<-60dB (from 88 to 108 MHz)

Power adjustment

Through the Vgs control Pin
3W<Pout<15W(Min)

RF Power OFF

Typ=-42 dB or 0 dBm Max

Input SWR

<1.3

Forward SWR detector

Through calibrated striplines

Reverse SWR detector

Through calibrated striplines

Board Dimensions

2.5*3.5’’

 

This FM amplifier has a 38 dB gain and provides 15W.
(No tune is needed to cover all the FM Band).

Présentation détaillée RDSTest Report

 

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