Came across this because I saw the commits referenced in one of RealAntennas' open issues that I happened to click on.
(@SernisD, saw your friend request on Discord, but lacking any context, I don't generally accept them. Didn't see until now your link to the RA issue.)

Please use BEFORE or AFTER for any MM patches that relate to a mod that isn't yours. This is because using FOR[x] will cause MM to create the pass x, and any patches that use NEEDS[x] will be satisfied. You are essentially telling MM, and every other mod, that x is installed. Using BEFORE/AFTER does not have this side-effect.

Can you adjust the patches in fbde543 to be BEFORE[zRealAntennas] and BEFORE[RealAntennas]?

Thanks, I've submitted a PR to fix that.

I wanted to ask you on discord if there was an easy way to calculate the dish size* needed to reach certain distances. KSPIE has two lasers that cover up 1.0e+13 and 1e+15 respectively. With the https://forum.kerbalspaceprogram.com/index.php?/topic/183536-181-galaxies-unbound-nova-kirbani-123-1-08-february-2020/ mod coming out soon, I'd like to ensure that people using KSPIE and Real Antennas can communicate over long distances.

Config files for reference - (https://github.com/sswelm/KSP-Interstellar-Extended/blob/master/GameData/WarpPlugin/Parts/BeamedPower/Transmitters/FELA/FELA.cfg#L419 and https://github.com/sswelm/KSP-Interstellar-Extended/blob/master/GameData/WarpPlugin/Parts/BeamedPower/Transmitters/FELT/FELT.cfg#L221)

Need to bound the question a bit more. There's a lot of variables: the dish size of each antenna, the configured transmission power, the configured frequency (RF band), the desired distance, and several configurable properties of the desired tech level. So can't really answer generally. Lock a few of those down, make a few guesses, and then it's fairly easy to tell you how much you want to modify the dish size.

Suppose you have 2 dishes communicating with eachother at the desired distance and rate that are X meters in diameter. If you double each of their diameters, you can reduce the transmission power for the same result by -12dB. A few rules of thumb, to change while keeping all others the same:
Double the distance: +6dB
Double an antenna diameter: -6dB
Double the data rate: +3dB
Double the frequency: -6dB between two dishes. +6dB between omnis. +0dB between a dish and omni.