SOE then explained the problem they were having dropping supplies to partisans operating across Europe, as far away as Poland. Brown explained that their beacon could be seen as far as under good conditions, but that might drop to as short as 5 miles if it was under trees or otherwise blocked. SOE stated that they could be reasonably certain to place it on open ground. However, they also stated that they could only navigate to perhaps ten miles of the beacon, which would be only marginally satisfactory. Brown asked why they could not use the Gee navigation system to address this, and when they admitted they had no idea what this was, he had the satisfaction of saying he could not explain it to them because it was secret.