5.2GHz power and antennas

I can’t seem to find a good explanation of the FCC regulations for 5.2GHz unlicensed in the US…

Does anybody know the max EIRP? I got from the Canopy manual that you can’t use a passive reflector with the 5.2 band, but I don’t understand why not if you turn down the output power of the radio with a 1:1 ratio to antenna gain? It would then still be putting out legal EIRP (whatever that is), but receive gain would be better. Anybody with a quick explanation of regulations and output powers for 5.2? I’m trying to decide if I should use 5.2 instead of 2.4 for a market, due to the much lower interference levels in the 5.2 band; but will it make a difference if output power is that much less? Trying to figure it out. Thank you!

Part-15 rules state that only certified systems are allowed (regardless of EIRP) and Motorola has never submitted the 5.2Ghz SM with a reflector dish to the FCC to have it certified because the dish would put the radio above FCC approved power levels.  Yes you can technically turn down the power to be with in FCC specs for EIRP but since the rules also state that it has to be a certified system it is technically illegal and the FCC could impose fines etc.

Page 496 of the Canopy Users Guide shows what systems have been approved by the FCC

FCC part-15 rules section 15.204 talks about the system needing to be approved to be legal.

if you live in rural area, and aren;t interfering with others. I highly doubt the FCC would even bother you about it. hopefully they have better things to do than worry about unlicensed freqs. usage

It’s never a good plan to knowingly violate FCC regulations. Sure, in a highly rural area your chances of getting busted are much less, but why take the chance, especially with a point to multipoint system.

Well to start with nucoles the original post was concerning the legal EIRP limits in the USA. According to the part-15 license (yes this spectrum is licensed contrary to your beliefs) there is technically no legal EIRP limit for a 5.2SM with a reflector dish because the system hasn’t been approved by the FCC.

As a business plan it is completely ridiculous to use radios out of spec. For each infraction the FCC can fine you around $10,000. Plus if you ever decide to sell you basically have a worthless network that no one in their right mind would want to buy and take on that liability.

In addition operators like you make our business much more difficult by not only polluting the spectrum but also giving the FCC ammunition for not releasing more spectrum for companies like us to use. If everyone is just abusing the rules then the FCC could just say “you know what we tried some different licensing schemes and look what happened everyone just did what they wanted and didn’t follow the laws.” We are lucky that they decided to license the spectrum to the equipment and not the operator. Otherwise we would have to raise billions of dollars to buy spectrum.

The FCC is currently working on releasing TV white space which is AWESOME spectrum. The wave lengths allow it to penetrate walls and trees etc. while also providing faster speeds because there is plenty of bandwidth for multiple channels. However, the incumbent TV broadcasters are trying to prevent us from using the spectrum because they fear that it will interfere with them. With operators like you around they have a very valid argument.

Please obey the part-15 license…it’s not a “guide line” to follow, it’s actually the law.

if you really want to cry about it, post it to someone who actually cares.

your lack of professionalism comes as no surprise to me.

If you would mind your own business and post to the person asking a simple question and give him the answer to it, instead of singling out people to disprove and b*tch about these forums might be more useful. So next time you want to disprove and correct someone do it in a polite manner insterad of being an a**hole. that must be a typical colorado attitude.

I’m not going to argue who is right or wrong at this point, because IMO you’re both out of line. Take this crap to PM so the rest of us don’t have to wade through it.

There are WISPs that are currently under investigation (in a rural area) for using 5.2 with reflectors. The fines are still coming…

Unless you are prepared to pay the fines (and they are hefty) stay within compliance. Unless you are prepared to pay the fines incurred by another WISP always recommend to stay within compliance.

5.2/5.4 is tempting spectrum. Unfortunately the max EIRP is 36dB and does not follow the same PTP rules as 2.4 and 5.7. Yes, you could switch to low power which is an 18dB cut and use a dish which is 18dB boost and stay within EIRP compliance. As was stated, 5.2/5.4 is not certified for use with reflectors so you would be taking your chances.

However, this is a topic of much discussion on the WISPA mail list and Moto has taken some interest. The solution has to be enforceable by the FCC so relying on WISPS to do the right thing and switch to low power or “dished” mode is not the best solution. I would like to see an alternate 5.2/5.4 radio that is capped at 5dB Tx and is meant to be used with a reflector (sold as a system). We’ll see what happens.

There are the extended range 5.2 backhauls that are capped at 5dBm TX output that are meant to be used with a reflector kit. The standard 5.2 backhauls however are not permitted for use with a reflector.

VLAN1 are you reading this? hint hint