This is one of those "I wish I'd known this years ago!" posts. But, better late than never.
Many DTVPal owners use a Dish 20.1 remote control to replace the one that came with the DTVPal. But I'd wager that few if any DTVPal owners use, or are considering, an RF modulator to pipe the output of their DTVPal through the coax cabling in their home. (It used to be that an RF modulator meant SD, but there are now some cheap ATSC RF modulators, so it's now feasible to pipe HD video from your DTVPal or other devices through your home on an unused RF channel.) But if anyone reading this thread does happen to fall into both categories - or knows someone who does - this post is for you.
One annoyance with using an RF modulator with a device like the DTVPal is that it's somewhat cumbersome to use. First you have to tune your (say) bedroom TV set to the modulator's channel - then you have to switch the remote to control the DTVPal. (Of course this assumes you have some sort of extender that lets your Dish 20.1 remote control operate your DTVPal from another room in the house.) It's easy to forget to change channels first, then try to pull up, say, your recordings list, and nothing happens on the TV. Then you have to switch back to the TV, change channels, then switch back to the DTVPal, etc.
Turns out the Dish 20.1 remote control has a poorly documented feature that simplifies this kind of setup. It's called "Auto-Tune Mode." Basically it lets you set your remote control to automatically change the TV to the correct channel anytime you press the "Sat" button (typically used to control your DTVPal): https://my.dish.com/support/sat-auto-tune
If you set up your remote control this way, all you have to do is press "Sat" and the remote will tune your TV to the correct channel automatically. Then go ahead and use your DTVPal.
Note: all the above still applies if your "TV" is a tuner (such as an iView) hooked to an A/V monitor.