Wireless modules FCC approved

[Michael]

I know this is off topic but it seems many of you have experience with the assortment of wireless choices out there.

I have a couple of Xstream X24009 OEM modules that I'm using right now and they're very impressive, good range and very reliable. Also, I think these are FCC approved right out of the box which is a plus for me.

BUT--

They're pretty pricey -- 100 bucks each

Does anyone have any other manufacturers with modules like these that are FCC approved at a lower cost?

I'll probably go with 900mhz for more range -- I need LONG range for industrial environments just to transfer RS485 data.

Thanks !

[mackrackit]

I like the LINX products. Buy from Bruce.
http://www.rentron.com/PicBasic/RemoteControl.htm

Generally speaking, the lower the frequency the longer the range given the power is equal at the antenna.

The higher freqs have the advantage of being able to pass through small openings. So it is harder to block the signal. Sometimes increasing the effective range over the lower freqs.

As far as FCC goes, it is a good idea to read and maybe understand Part 15 of 47 CFR.

Some frequencys are legal only at certain powers.

Make sure you use an antenna that is matched to the frequency being used. Dave Houston has good info on his site. Worth a read.
http://davehouston.net/

[Michael]

Thanks.

Some of these (I think) don't require an FCC lab test if put into a product though....I'm interested in something like that because ALL xmtrs (if sold as a product) require FCC approval, right?

I'm not even sure my Xstream are like that.

Just discovered the Xcite -- didn't know about them -- only 40 bucks.

I know there are some modules out there that you can just put in a box that are already FCC approved.

Can't remember where I saw them.

[Michael]

Also -- If you had a choice, everything else being equal....

In a typical modern office building with a lot of steel construction etc would you...

2.4ghz at 50mw

or

900mhz at 100mw

?

What's the general consensus on that?

A real difference or 6 to 1?

[dhouston]

AFAIK, anything sold assembled and ready to use requires FCC testing. The testing is expensive which (in part) explains the high cost of pre-approved modules. Even receivers require testing - it's not only transmitters. You really need to read the Part 15 documentation.

• http://www.fcc.gov/oet/info/rules/

Her's a link with some data on indoor propagation.

• http://sss-mag.com/indoor.html

[Archangel]

Higher the Frequency, the more line of sight the signal becomes, lower the power the shorter the range, that said the higher Frequency units might be a little less affected by noise.

[Bruce]

Even if you toss a pre-certified module into your product, it will most likely still need FCC
cert before you can sell it. Contact one of the certified test labs if you aren't 100% sure.

These guys are one of the best http://www.celectronics.com/

The finished product (even if it uses a pre-certified module), may still need final certification
of the finished product before you can legally sell it.

An FCC certified test facility will tell you straight-up if your product needs further FCC cert.

They will tell you without charging you for the info, and it's worth the effort.