The small rectangular antenna in the left hand side of the case came with the device (Lilygo-T-RelayS3). The larger one outside the case came from a different device (Old Particle Photon).
I was wondering if the larger one will necessarily get better signal or might I be opening up a can of worms?
Thanks
It's hard to say just by looking. An antenna is matched to a specific device, not only by frequency, but by impedance. If the Lilygo-T-RelayS3 has a series inductor (base loading coil) to compensate for a shorter antenna, and the Old Particle Photon does not need one, since the antenna is longer, there could be an impedance mismatch that reduces the signal.
Worse, with some devices, a badly-matched antenna can cause high standing wave ratio (SWR), which can raise voltage on output transistors and destroy them. On the low-power Lilygo-T-RelayS3, that is not as likely as on a high-power device, but there is a small risk of damage in switching antennas.
