This article originally ran in early 2014. The answer has changed.
No. and here’s why.
Most of those models include a power connector that’s compatible with the AM21 but in the case of the H25 and HR44, you can leave the passthrough connector disconnected and use the regular power supply.
What you see above is the original answer I wrote years ago. However, since then the AM21 Antenna Module has not only been discontinued, bur support for it has been dropped from most of DIRECTV’s line. Even more receivers will lose support for this module in the coming months and sometime before the spring of 2019 support for over-the-air antenna signals into DIRECTV receivers will be completely removed.
If you have a working setup now, it will continue to work until necessary updates to the receiver software are made. That could be anytime. There is a hard cutoff date however since DIRECTV has no plans to keep its channel database up and within the next 18 months most channels will be changing frequencies.
The best thing to do is to use an external DVR instead of connecting to your DIRECTV box when support for your receiver ends.