Excellent question...
-----Original Message-----
From: Ken Hohhof
Sent: Friday, September 02, 2016 5:29 PM
To: [email protected]
Subject: Re: [AFMUG] antenna gain from return loss spec?
Hmmm, so Ubiquiti is just choosing not to publish the gain vs freq
information. Pretty much all dishes have a sweet spot in the middle of the
5.7 sub band and drop off several dB at the low end (4.9 or 5.1 GHz).
I wonder why they think RL is a more important spec to publish vs freq than
gain?
-----Original Message-----
From: [email protected]
Sent: Friday, September 02, 2016 6:23 PM
To: [email protected]
Subject: Re: [AFMUG] antenna gain from return loss spec?
Yes, but your return loss would have to be much worse than this to have a
noticeable effect.
Think of it this way: A 3dB RL means half the signal is getting bounced back
into the air or back into the transmitter. So your antenna gain would be 3
dB less.
A RL of 10 (which is still pretty bad) means you are losing .457 dB.
Most antenna manufacturers shoot for 14 dB minimum.
That is a .17 dB loss of gain.
-----Original Message-----
From: Ken Hohhof
Sent: Friday, September 2, 2016 5:13 PM
To: [email protected]
Subject: [AFMUG] antenna gain from return loss spec?
If a 5 GHz band antenna has a gain spec of 23 dBi and a graph of return loss
vs frequency, is there a way to translate this into gain vs frequency?
We put up an AF5x link today with the 23 dBi antennas and actual Rx signal
was 6 dB less than ideal. But that would make sense if the antenna gain was
actually 20 dBi at the freq of operation 5230 MHz.
