BLE scanning: How complex is it to force scan on only 1 BLE channel?

I am scanning all the time, yes:

// Start scanning
NRF.setScan(function(d) {
  console.log("found",d.id,"with MD:",d.manufacturer,", with rssi=",d.rssi,"!");
}, { filters: [{manufacturerData:{0xDEAE:{}}}] });

Results seems better when laptop is not connected to the receiving node but the statistics previously given have been established in disconnected mode.

It makes me think that I did not try to stop the receiver from advertising itself, or at least limiting the advertising, I will definitely give it a try and share my results.