So I bought it, as adviced by members here.... thank u 
I bought 2 versions. Dog one and drone ones, with 3 + 3 transmitters.
I plan to use the dog version for experimental SAR, because transmitter is waterproof a bit.
900 mhz goes thru walls much better than 2.4ghz for sure.
While going thru walls cause multi path signal, this unit is quite smart and at least I can still get signal reception strength even when the Radio Direction Finder function get confused to signal source direction.
It actually has better thru water transmission better than 2.4ghz.
It can almost transmit 30cm thru water, compared to 2.4ghz which will get cut off within like 5cm of water, at least that is how I managed to test, as long as line of sight is straight.
This baby receiver reminds me of my gang old Sitex RDF on a boat
Si Tex 525 ADF with antenna
So holding the receiver flat as in LCD screen viewing the sky is a must, as that is when the positioning of the 4 antennas is proper. I saw such info in a video review, but only when I got the device I realized them flip doors are the 4 directional antennas.
End of Report.
I bought 2 versions. Dog one and drone ones, with 3 + 3 transmitters.
I plan to use the dog version for experimental SAR, because transmitter is waterproof a bit.
900 mhz goes thru walls much better than 2.4ghz for sure.
While going thru walls cause multi path signal, this unit is quite smart and at least I can still get signal reception strength even when the Radio Direction Finder function get confused to signal source direction.
It actually has better thru water transmission better than 2.4ghz.
It can almost transmit 30cm thru water, compared to 2.4ghz which will get cut off within like 5cm of water, at least that is how I managed to test, as long as line of sight is straight.
This baby receiver reminds me of my gang old Sitex RDF on a boat
Si Tex 525 ADF with antenna
So holding the receiver flat as in LCD screen viewing the sky is a must, as that is when the positioning of the 4 antennas is proper. I saw such info in a video review, but only when I got the device I realized them flip doors are the 4 directional antennas.
End of Report.
