Now doing things by FCC requirements, doesn’t switching to higher gain antenna basically become a ‘wash’ if you are required to lower the power?
Now I know certain antennas narrow the beam, and that can help for certain spots.
But to me, if i got from 10dBi stinger antenna at full 26dBm power to a 17dBi yagi and have to turn the power down to 19dBm, isn’t that just a waste? Or am I missing something.
I’ve been playing with scenarios in Radio Mobile and thats what i’ve been seeing.
Note this is all 900mHz stuff, be relevant to the other freqs i’m sure.
We’ve found that in most cases a connectorized 900SM w/ M2 yagi will provide a more reliable link than the integrated antenna. Not all antennas are created equally even when they have the same dBi rating.
Also remember that gain is both ways - increasing your TX power doesn’t raise the level of the received signal on the same unit.
So if I thought this through.
Increasing Gain of Antenna (and legally dropping power levels) of the SM we would technically see greater signal strength from the AP.
But on the other side the AP would most likely see the same level as the overall power output is the same. (but could be better since a yagi tends to focus the beam more than say a small sector)
There is more to it.
An antenna with a very narrow pattern also rejects off axis noise improving the signal to noise on the receive side. This is why front-to-back rejection is so important in antenna design.
silentsno wrote: Now doing things by FCC requirements, doesn't switching to higher gain antenna basically become a 'wash' if you are required to lower the power?
Now I know certain antennas narrow the beam, and that can help for certain spots.
But to me, if i got from 10dBi stinger antenna at full 26dBm power to a 17dBi yagi and have to turn the power down to 19dBm, isn't that just a waste? Or am I missing something.
I've been playing with scenarios in Radio Mobile and thats what i've been seeing.
Note this is all 900mHz stuff, be relevant to the other freqs i'm sure.
Yes if you go by EIRP then 36 dbm is 36dbm (4 watts) transmit power EIRP. I think the FCC allows for cable attenuation so any coax or connections between the radio and the antenna will decrease the power at the antenna. The radios pigtail, and if the antenna has a short pigtail this would be a small power attenuation, 1/2 to 1 db perhaps.
With the yagi your putting that 4 watts into a narrow beam width, kind of like a spray bottle set to spray or stream, the narrow stream will go a greater distance. Same thing on receive gain, the yagi will have more gain on receive and rejection of signals "noise" not in beam path of the antenna.
If you ever get visit from the FCC it will due to the fact your causing interference to a licensed user. Most times interference complaints are handled by mail, you get a letter from the FCC that your causing interference to blank and your ordered to eliminate it.
higher gain is never a wash vs. higher transmit power. gain is a BI-DIRECTIONAL characteristic. it will result in better receive levels if nothing else.
Hi
I see you guys use 900 Mhz? We have come out with a 17.5 and 14.5 Dbi Yagi antenna. If you’re interested please go to our web site and take a look. If you have any questions give me a call.
www.kpperformance.ca
Take care
Ken