Help me select PIC and RF modules for 40m transmission

hi everyone,

project i'm currently doing involves PIC microcontroller and RF transmitters and receivers. I guess some of you already have some experience with this staff. distance beetwen receiver and transmitter will be approximately 40 meters. i'm not shore which modules to take, which product to choose and from which company (desired freq. is 433mhz), i heard some modules are really crap, like they can't reach even few meters. for that distance, should i get some good quality antenna or homemade one will be just enough.

thax in advance!

Re: PIC + RF modules

It depends on the kind of RF modules you bought and use.
Some come with PCB antennas.
Some come with RF SMA connectors for you to connect to an external antenna.

The kind of antenna affects the radiation pattern or the azimuth, this affects the energy to be directed from your Tx to Rx.
For very directional radiation pattern, use horn.
For omni-directional (equally all-rounded) radiation pattern, use PCB inverted F antennas.
The matching between the antenna and the PA also play a part. If the matching is poor, this will reduce the efficiency your antenna can radiate the Tx energy. You need to check the specification of the RF module to make sure the matching is good and the kind of antenna the RF module will support.

I personally find that RF modules made in Korea are poor.
The ones from Taiwan are good, but they don't really pass FCC compliant tests well because they radiate strong energy.
The ones from Europe and N.America are perhaps good in performance and compliant, but expensive in prices.
Some from Hong Kong, Singapore and China are pretty good too.

Re: PIC + RF modules

If you want a reliable ans cost effective solution, check out the following link:
www.linxtechnologies.com/index.php?section=products&category=rf_modules
I have done extensive research on this subject myself.

Don't forget about the FCC.

Re: PIC + RF modules

I have try with aurel modules with very good results. You have cheap modules for AM/OOK and FM/FSK for 433, 868 and 2,4 GHz.
There are maxim 2,4 GHz AM/OOK low-powered modules with very goog results as wel.
Don't forget that Am modules are noisy and Manchester encoding and perhaps come error control should be necessary.

PIC + RF modules

I have the experience about using 8051 with wenshing's rf module(2.4g). This module base on nordic's nrf-2401 chip, and wenshing's module can transmitte more than 50 meter, I think you may try this module

https://www.wenshing.com.tw

Re: PIC + RF modules


Where can i get these modules.
what is approximate cost of these modules.

I bought one TX-RX pair below 12$

Re: PIC + RF modules

This could be helpful to you.
http://www.rentron.com/ruf-bot.htm