Dual Band IR on HR20 and 21?

[jborchel]

I'm about to buy an infra red (IR) repeater system from Monoprice but their device doesn't support dual band IR electronic devices. For instance, many users say it won't work with their Denon receiver because apparently all of Denon's stuff is dual band IR. Does anyone know whether the Direct TV receivers are dual band or single band IR. The user manual doesn't say and tech support couldn't/wouldn't answer the question.