Yes, it's possible to load the TVGOS guide from an antenna during the night, and use the EH50 to control DirecTV during the day, but it's a little tricky.
First you should verify that the EH50 can control your DirecTV box. If not, then the rest is moot. If you find a IR blaster code that works, and *if* you're ambitious, then you can proceed to the next step. :-)
Here's what I do, and it is working great.... I have a EH50 and a Panasonic DirecTV box. I use a cheap auto-swith from Walmart (Philips brand) to assist with the input switching, and I use a URC-8090B Remote Control to automate the operation.
I connect my antenna to a VCR, which is used to tune the desired TVGOS channel. The A/V output from the VCR goes to the Philips A/V auto-switch. The DirecTV A/V goes to another input on the switch. This is one of those switches that will automatically switch when an input is active. I have the switch set so that the VCR A/V signal takes precident over DirecTV. Ie, when the VCR is On, the VCR video goes through the switch. The output of the switch goes to the EH50.
Every night my remote control (URC-8090B) turns On the VCR at the desired time, and it turns Off the EH50. The devices remain in this mode for 6 hours, during which time the EH50 loads the 3 sets of TVGOS data. After this period the VCR is turned Off and the EH50 On.
Throughout the day I can use TVGOS to control my DirecTV box, and it works great! It will be a sad day when NTSC broadcasting ends and TVGOS is lost, but at least this system works for a couple of more years.
There are a few other non-simple steps, such as hammering the correct TVGOS channel into the EH50, and knowing the correct times to load data, and programming the Remote Control. I don't have my detailed notes with me at the moment, but if you're interested in doing the work I can send more detail on how to complete these steps. Just let me know.
All said, it would be much easier to buy a new DVD recorder. :-)
But, I love my EH50, and better yet I was able to get it for $149 when Frys was clearancing their last unit.