Sirius XM Radio ( NAS: SIRI ) got a boost form a positive analyst note today. Barclays Capital analyst James Ratcliffe is feeling more upbeat about the only game in town when it comes to satellite radio. Ratcliffe's rating on Sirius XM is going from Underweight to Equal Weight. Yes, "Equal Weight" is the equivalent of a neutral rating, but it is a bold step for an analyst that was suggesting that investors short Sirius XM in the past. OK, so technically Ratcliffe wasn't telling investors to blindly bet against the company itself. He has suggested buying Liberty Media ( NAS: LMCA ) as a way to cash in on Sirius XM at a discount and shorting the exposure equivalent of Sirius XM shares. In other words, it would be an arbitrage play based on the narrowing discount between the value of Liberty Media's effective 46.2% stake in Sirius XM and the actual market value of the stock.