Same with the iPad app and the DIRECTV web site GUIDE. There's no way to schedule OTA recordings.
If you think about it, since OTA channel assignments are different in every market, the apps (or the web site) would have to know specifically which OTA channels are available for each customer. OTA is probably such a small % of overall usage that it likely doesn't justify the work that would be involved in making this happen. Just my .02.
That said, the iPad app will see OTA recordings in the playlist, but doesn't identify them as such.
The Nomad device will not show you any OTA recordings are available to download. That one puzzles me, because they are already recorded and should be eligible for transcoding, IMO.