The manpack radio has a neat extented range of 700m and provides a larger frequency band compared to the handheld radio. But 50 supplies is not worth that and more an artifact from legacy conflict.
So for HQ conflict the price should be lowered. For example to 5 supplies.
Additionally it would be nice to see it repurposed for a game mechanic.
Some different ideas of varying quality:
New standard channel set for manpack radios outside of the frequency of the handheld radios (instead of it being set to the Platoon channel). Like a command channel, a high level channel or a secret channel.
Only Squadleads/Units icon on the map are shown who/which also have a manpack radio on them or in their squad.
More extended range for backline operations.
Only Squadleaders with a manpack radio see the position of their squadmates.
Only Squadleaders with the necessary rank and a manpack radio can recruit and order AIs in their squad.
Manpack radios provide a +1 to capping manpower. So 1 defender vs. 1 attacker+manpack radio -> capping. But maybe a limit to +1 overall. So 2 attackers with both manpack radios still provide only a +1. (Price increase to maybe 150 supplies). This also applies to defenders.
Manpack radios provide an option to check for enemies in the area. So attackers can check if there are still defenders hiding in a point. And defenders can slowly figure out where the attacker is hiding which stops them from building.
I personally would simply like the lower price + a special channel set outside the handheld radios frequency.