Outdoor Digital Signal Retrieval

I’m dealing with persistent interference that is crippling Wi-Fi gear in an outdoor setting. The issue is clearly RF-related, but I haven’t been able to pin down where the unwanted signal originates or which exact frequencies are involved... (Budget: $1500 - $3000 USD, Jobs: Digital Signal Processing, RF Site Survey, Signal Processing, Technical Writing, Wireless Coverage Assessment, Wireless Network Risk Analysis & Reduction, Wireless Network Security Analysis, Wireless Site Survey)