Currently looking at different antenna specs to use with T-Beam but was curious if anyone knew what the gain rating of the stock antenna that comes with the tbeam is graded at?
0 to a minus number I expect. Manufacturers often chuck what they have the most of lying around into the packets. But at least it’s better than no antenna.
Antenna “gain” may not be what you think it is, and it may not be beneficial depending on your application.
“Gain” does not create more RF receive/transmit energy. Instead, it distorts the RF pattern around the antenna: i.e., it focuses the available energy - increasing it in some directions while reducing it in others. So, an antenna with “gain” is more directional than an omnidirectional or non-gain antenna. Consequently, unless you understand the RF pattern around the antenna, and you can keep the increased gain part of the pattern pointed toward the other station, you may be better off with an omnidirectional or non-gain antenna.
Having said the above, some gain antennas just flatten the RF pattern into more of a pancake shape so most of the RF energy is directed toward the horizon as long as the antenna is held vertically. This may help if you can keep the antenna vertical, but if you can’t, such an antenna may reduce signal strength between two stations.
Another situation where a non-gain antenna may be better is when the only RF path to another station is one where the signal is bounced off of objects. The line of sight path may be blocked by buildings, trees, or hills, so the only signal that may reach the other station may be one from an unexpected direction. Gain/directional antennas may not receive such signals as well as omnidirectional antennas that work well in all or most directions.
Omnidirectional antennas are typically better in situations where the other station(s) can be in any direction relative to your station, and where RF signals may need to take indirect pathways.
One final thought. The signal strength for most single-element antennas is strongest perpendicular to the antenna and weakest off the end of the antenna, so don’t point the end of the antenna toward the other station.