how to choose wireless module

Wireless & IoT
1

Hi,

I am designing a wireless project that needs to work 200ft indoor U.S. house and ~ 800ft outdoor. the data rate is just manual on/off control.

my research on web is that those cheap 433mhz module wont work for these ranges.

I wonder what other options do i have. i understand FCC has different power limits at different band. so on 9xxmhz or 2.4G band do i have to run FSSS or DSSS to achieve the range i want or single frequency FSK will do the job.

thank you very much

william

2

You won’t get that range at 2.4 GHz without directional antennas.

Leon

3

chocheng:
Hi,

I am designing a wireless project that needs to work 200ft indoor U.S. house and ~ 800ft outdoor. the data rate is just manual on/off control.

my research on web is that those cheap 433mhz module wont work for these ranges.

I wonder what other options do i have. i understand FCC has different power limits at different band. so on 9xxmhz or 2.4G band do i have to run FSSS or DSSS to achieve the range i want or single frequency FSK will do the job.

thank you very much

william

With XBee PRO (60mW), 2.4GHz, you can probably meet your range goals. Outdoors, 800ft. is do-able if it’s near-line-of-sight, and/or if you use a patch antenna on one or both ends. These are $35 or so and sold on SFE. They are robust bi-directional and a big overkill for just on/off remote control. But cheap.

It’s hard to do on 433MHz AM “OOK” modules as most all use 1mW and have poor range, and antennas are rather large at that freq.

In the US, 433MHz requires a very low duty cycle of transmission since there is no requirement for CSMA (listen-before-transmitting). This may be more important that radiated power. High antenna gain in a uni-directional link, at the receiving end, is the cure for long range in this scheme, along with a seriously robust error correction strategy based on lots of FEC and redundant transmissions.

For a hobby project, adapting an aircraft R/C receiver/transmitter might work.

Or with more software work, one of the wireless Tx + Rx pairs might work, if you choose one with sufficient Tx power. Do a simple link budget.