I have RXTX-433M RF modules........ in order to increase the range b/w the Transmitter & Receiver to communicate........ I plan to make a amplifier......... can a class A amplifier hooked on before the antenna section on Transmitter module will work???? or Class C???? plz give me a good circuit diagram too as I couldnt find one on google! Plz HELP ME!!!!! Remember that the Transmitter & Receiver is used for activating relays and not for any audio signals! i just wanna increase the RANGE of this system!!

Ask here

 

allaboutcircuits.com

Whether you want class A or class C would depend on what you need for your particular construction. A has a lower efficiency but is simpler and has (I think) less distortion. C, on the other hand, has high distortion but a very high efficiency. From the sounds of it, distortion is less important, so you'd go for efficiency, which means a class C amplifier.

 

As for diagrams, look here:

http://www.electroschematics.com/tag/rf-amplifier-circuits/

 

Edit: I take that back. Look here instead:

http://www.angelfire.com/planet/sft_accommodation/rf_amp.htm

Edited June 5, 201312 yr by pwagen

Many things have to be considered...

What is the current power you are using ?

What is the distance wanted to reach ?

Is there line of sight between units ?

Will it be 2 way communication ? If yes, you will have to amplify the transmitters at both ends.

Have you tried by using high gain directional antenas instead of amplification ?

 

Here arew some links of interest:

http://www.abacom-tech.com/%2F433MHz-RF-Power-Amplifier-PLA-05W-P93341.aspx

http://www.flytron.com/openlrs/108-7w-booster-for-uhf.html

You may find kits too.

 

Look for SKYA433YAG125 at: http://www.skyrfid.com/Antenna_UHF_433_MHz.php