If you use an extension cable to relocate the original antenna, the worst thing to happen will be that you lower the throughput per single device at 5 GHz (plus the outdoor signal will be reduced by the attenuation of the cable, not a big deal unless you use a really thin one). I'd expect the actual bottleneck to be the uplink at most sites, though.
You can test the amount of speed reduction in advance by setting tx-chains=0 rx-chains=0
(or tx-chains=1 rx-chains=1
) for the 5 GHz interface and comparing the throughput of the same device on the same place to the default state with tx-chains=0,1 rx-chains=0,1
. Before starting to tamper with that, check the default state, though: :put [/interface wireless get wlan2 tx-chains]
, there may be a different number of chains on hAP ac³ than on my hAP ac².
If you use a different antenna as the outdoor one though, it has to be a dual-band one as well so that you could use it to improve reception at 2.4 GHz as you've planned originally (which only makes sense if the attenuation of the cable is lower than the attenuation of the signal pass through the body of your RV).
Few more details regarding rx-chains
can be found in the documentation
An important point, be aware that by using any other antenna than the one which came with the device you are breaking the conditions of the FCC certification of the device, even materially if the other antenna has a higher gain than the original one in some direction by more than the attenuation of the extension cable.