40 Meter QRSS Beacon II

After monitoring the QRSS beacon for almost a week I noticed something interesting. I had been using Spectran by I2PHD to capture the beacon but have now switched to QRSS VD by AJ4VD which allows me to easily review many hours of collected traces. It seems just after sunrise when the building where the beacon is housed gets heated by the sun the beacon frequency raises by 10-20 Hz and stays there all day and then cools down at night. Click the image below for the details. This is about a one hour segment and starting at 8:40 AM this morning it starts to go up and stabilizes at 9:05 AM.