Count unique phrase

Hello,

I have attached an abstract of a spreadsheet which has a series of data and although I can work out various things, I'm stuck on the following:

Typical phrase is:
2010-08-01 10:24:00 +0000 1709120029: Device found: 00:23:d7:0f:26:25 (RSSI -90)

1. The serial number 00:23:d7:0f:26:25 can repeat a few times, and want I'm looking to find out is the number of unique serial numbers within the document

2. Im also looking to find the number of times the phrase "device found" is found in each hour of each day

3. And lastly Im looking to know the number of times serial number with RETRY exists for each serial number, so I can say there were x number of 1 RETRY, y number of 2 RETRY, z numbers of RETRY etc etc

Hopefully some of the Excel experts on here can help me solve this as its driving me mad!

Cheers