switching from 2.4ghz to 5ghz

how do you switch the mikrotick r52nm wifi card from 2.4ghz to 5ghz?
https://mikrotik.com/product/R52NM

i have been using the mikrotik rb411 router as a wireless bridge client with
the r52nm 2.4/5ghz mini pci 802.11a/b/g/n dual chain, high power daughter
card as a 2.4ghz wireless transceiver and wanted to try out the 5ghz option
on that card to see if there's less local noise in that 5ghz range.
https://www.microcom.us/r52nm.html 

i didn't change the 2.4ghz mesh antenna because i just wanted to switch to
5ghz to see what would happen. i assumed the two mmcx jumpers were for the
2.4ghz and 5ghz respectively so using that assumption i swapped the mmcx
antenna connector from the left side jumper (j4) to the right side jumper
(j5) but the signal strength went to hell.
https://www.roc-noc.com/pdf/R52nM/R52n-M.pdf

i can't find an owners manual other than this advertising literature.
https://www.roc-noc.com/mikrotik/minipci/radio/R52nM.html

do you know how to switch the r52nm from 2.4ghz to 5ghz?