RF Power Amplifier Use

[Coeylin]

Hello all,
I am currently working on radio transmission and reception at the frequencies of around 200MHz. The range of transmission is not currently important.
It is enough if I could transmit for 10 meters or so. My question is, Is it necessary to have a rf power amplifier? Can an ordinary gain block can be used? Will antenna be able to radiate without PA?

Is there anyone ideas of it? Thank you in advance.

 

[IndianEars]

Hello Coeylin,

You may not require a separate RF Power amplifier for small distances as long as you are taking care of the 2 points below

1. What is your current Output Signal level? Is it 1 Volt Peak To Peak ?
Incase you have a signal on 1 mV to 100 mV, you can use an in expensive Cable TV (CATV) RF amplifier, it will provide you an output of 1 Volt.
Cable TV RF amplifiers work well over a bandwidth of 45 MHz to atleast 550 MHz and most will work to 1 GHz.

2. Are you feeding a Dipole antenna designed to match the output impedance of your electronics ? This is crucial, else the output signal will be wasted.

Later if you want to increase the range, use a directional antenna instead of an Omni Directional Dipole. The Directional antenna will focus the signal in the intended direction.

Keep in mind that the transmission range is proportional to:
a. The Square ROOT of the Power
b. Directly proportional to the antenna Height.

So if you double yr output power, range increases by x1.4
But if you double yr antenna Height, you double yr range !


P.S: Not sure if this is the appropriate section in this forum to post this query... May be in the general discussions, since this is an Audio Forum