Do you have a dect phone? (cordless).
When you say you can't receive that frequency, are you saying that you get no signal at all?
Do you have a dect phone? (cordless).
If you do, try powering it down and try again.
With my last dect phone, there were several frequencies I couldn't get because of it causing interference.
When it dies and I got a new dect phone all was ok again.
Dect phones if they cause problems can either stop you getting certain frequencies or they cause the signal to fluctuate wildly on certain frequencies.
Try moving the Dect base unit, you may find a position where it does not cause interference.