Hi, I am relatively new to choosing antennas so I would appreciate some guidance on it. In this post, I have laid out my knowledge and questions/concerns I have. Thanks, and any help would be greatly appreciated!
So, I have RFD900 modules which currently don’t perform great at all, I get maybe a kilometer range with them (I have tried playing around with the settings but nothing is reliably working well with range). Changing the antenna could potentially fix this. I was thinking of purchasing a directional high gain antenna. The current system I have has a gain of about 2-3dbi. The new ones I am looking to purchase have a gain of around 15-17.5 dbi. For an example of the type of antennas I am looking at, here’s one: Kp Performance 17.5dBi 900MHz Single Pol. Yagi Antenna (5-Pack) (ispsupplies.com).
My concerns start with the fact that some of these antennas have input/max power rating which is much higher than the output power of the rfd900 module - about 1W output power for rfd900, but the antennas I found with high gain are input/max rated for anywhere between 50W (the link above) to I found some with 500W. Ardupilot’s guide, however (screenshot, the links no longer work), mentions some of the similar spec antennas (their doc is using a 433 mhz module).
Since those antennas are such high power, are they compatible with the rfd900 modules I am using? I’m worried that the telemetry modules won’t be able to make use of the larger antennas because of it’s input/max power output. I’m not convinced that the 1W RFD 900’s can be effective with those 50 to hundreds of Watts antennas. I know 100W is “rated” and you can use them at a lower wattage. What I am worried about is the RFD 900 not being able to make use of the huge antenna or barely being able to “saturate” it with enough juice to actually get a usable signal out of them, let alone improve range. But then Ardupilot’s guide recommending those antennas makes me question otherwise as well. So that’s where I am stuck.