Some FAQs on the Blaze website re the software:
Computer TV PCI cards and USB sticks require a decent signal to work properly, especially as the digital signals (until your area switches off analogue) are only a fraction of the analogue transmission strengths.
If you have to use an indoor aerial, this one from Argos will almost certainly be a better bet (just £9.99):
One of these aerials is used with a Sony 15in TV and cheap Freeview set top box and works well. I tuned the STB first on the main TV set and outdoor aerial, before transferring it to the Sony and STB.