Is possible to use a directional antenna and omnidirectional antenna on the same radio in a bridge or Ap, its this configuration possible or there is any restriction to the respect ???
I'm suning a Brdige AIR-BR1300
Do anyone know something to the respect???
Dual antennas for the same radio must be lookig at the same general area (for "Diversity" - makes better communications (in that one area)).
It is not to use the AP as a relay / bridge / repeater between two areas.
As scottmac said, you should only use two similar antenna on one bridge. The two connectors are for diversity only, if you connect two directional antenna pointing in different directions it will confuse the bridge totally! To make this setup work you would need two bridges each with one directional antenna pointing in different directions.
it is possible to combine both Omni and directional Antenna. You can use an HF Splitter on ONE of the Radio Interface Connectors, so diversity is not given.
No to the "splitter" (as a generic term).
There are "power dividers" that can be used, with a great penalty, to the signal.
"Splitter" tend to refer to a receive-only environment (think - like a cable TV splitter). A power divider is designed for a transmit/receive environment; it can handle the power from the transmitter .
Putting in any device like a power divider will (by definition) drop the signal at least 3db (half + losses) ... typically more, because they are usually fairly inefficient devices (I believe ~-5db is typical (more with losses from the extra cables & connectors).
Also be advised that in most regulated domains (FCC in the US, ETSI in the EU) by implementing outside the manufacturer's designed system, you lose the operational certification and could be in violation of your local regulations.
Using these kinds of devices (amplifiers too) is a bad idea unless you know what you are doing.
Follow the manufacturer's design specifications and you're most likely to produce a well-functioning, legal system.
if you are looking for multiple antenna's etc, do a search on hyperlink technologies, they have all the multiple antenna connecters and amplifiers.
25 watt amplifiers rock :)
Aside from the fact that using a 25W amp in this environmnet is like using a 12Ga shotgun to blow a spec out of your eye ...
This is an extremely dangerous power level; hazardous to people's health ... long term exposure will seriously damage or kill your average human (unless specific safeguards are taken).
In many places, it'll also get your equipment confiscated, a fine (~US$10,000.00 to start), and possibly prison time.
If you've actually implemented a system with a 25W amp without the appropriate design, you've almost certainly done a Very Bad Thing.
I'll bring the marshmallows and hotdogs to that install, if someone brings the hangars ;)
I have seen designs where a bridge is set to receive with a dish antenna and transmit with a yagi, or some other type antenna, to be able to not go over the EIRP of 4 watts.
That way you can stay within 4 watts of transmit power, but use the biggest antenna you can get to recieve and boost your signal with the antenna gain.
25W is perfectly fine for outdoor point-to-point connections. In fact, the FCC allows almost 200W using 11a outdoors with highly directional attennas.
For indoors and outdoor omni-directional, absolutely ... 25W is illegal and dangerous!
The last FFC rule I read (maybe out of date) says you are allowed a max of one watt at the intentional radiator (the entire system minus the antenna).
The 200 Watts is(was?) EIRP (radiated power: input power + gain of the antenna).
To stay legal with a 25W amp, you'd be limited to a 9db antenna.
Then there is (was?) a requirement that the system be certified for compliance. Changing or adding a component that isn't certified, as part of the system originally certified, removes the certification.
I believe the rules now allow you to substitute a similar item (cabling, antenna,arrestor) and maintain the original certification.
Pumping 25W into a Yagi or dish (or omni above 9dbi gain) is almost certainly illegal in the US, and probably illegal in most countries.
For as much as I love curling up by the fire with a good FCC regulation manual, I've been pretty busy lately and haven't had the opportunity: Have the rules changed in the last year or so?
A twenty-five watt amp, at these frequencies, in the hands of a casual installer or end-user, is an extremely Dangerous Thing.
The rules are different for point-to-multipoint and point-to-point for 2.4Ghz and 5.8Ghz. See below...
Power output rules for 2.4Ghz PtMP:
max (intentional radiator) IR: 1watt
max EIRP: 4watts
max antenna gain: 6dbi
1:1 anttena rule applies ... for every 3dbi of additional attena gain the IR must be lowered by 3db.
Power output rules for 5.8 Ghz PtMP:
low band IR: 40mw
mid band IR: 200mw
high hand IR: 800mw
max antenna gain: 6dbi
1:1 antenna rule applies
Therefore, max EIRP per band= low-160mw, mid-800mw, high-3.2W
Power output rules for 2.4Ghz Point-to-Point:
Same as 2.4Ghz PtMP except that 3:1 atenna rule applies. For every 3dbi of additional atenna gain the IR must be lowered by only 1db.
Therefore, if you have a 30dbi antenna you can legally be transmitting at 158W!
Power output rules for 5.8Ghz Point-to-Point:
Low and Mid bands follow the exact same rules as Point-to-Multipoint.
The High band (UNII-3) however may employ a directional antenna up 23dbi with no reduction in IR power. Therefore, a 28dbi antenna connected to a 800mw IR = 160W of legal EIRP!
See pages 305-309 of the CWNA study guide as a reference to the figures above.
Hope this clarifies,
Brad: how do those specs show a 25W amp is legal? I agree with Scott that 25W amps are very dangerous and I don't see any situation where they fall into the legal category. What you posted seems to back Up Scott's statement that the max output of the IR would be 1W.
First, lets make sure we are in sync with the terminology.
IR is the power at the intentional radiator. The intentional radiator is everything EXCEPT the antenna. In other words ... What is the power at the point that connects to the antenna? That is the IR.
EIRP is Equivelant Isotropic Radiated Power. This is the power observed after being transmitted by the antenna in the RF medium. This is the power actually transmitted into the air.
Again, Yes, the max power at the IR (before the antenna) is 1W or less.
However, the max EIRP (what is actually transmitted in the airwaves) can be as high as 160W. And again, these rules apply to Point-to-Point links with highly directional antennas. Your typical omni-directional indoor network falls under a different set of rules.
If we could only transmit at 4W for point-to-point links it would be impossible to provide long distance bridge links that span many miles across a city.
With highly directional antenna, the energy is concentrated in a beam and not spread about with broad exposure.