Wow, I had that wrong! I thought you were trying to get an FTA satellite dish working with one of the DirectTV cables, I see from the pictures that it's an OTA antenna! Ok, disregard my previous post! Check what Lak7 suggested, that there isn't a satellite switch somewhere in the cabling, it'll look something like a splitter. if there's a switch somewhere, it won't pass the OTA signal.
If you have an ohmmeter, with both ends of the cable disconnected, you can measure from the center conductor to the outer and it should read infinite, no continuity, if it doesn't then the cable is probably bad, or there is a switch or something somewhere in the mix. If that test is good, with both ends of the cable disconnected, short the center connector on one end to the outer and measure across the center and outer connector on the other end, you should have continuity that way with very low resistance. If the resistance is high than the cable is probably bad, or a switch or something is in there somewhere.
Check that the cable is RG6 and not RG59. It's probably [and should be for an OTA antenna and DirectTV] RG6. IT should be marked right on the side of the cable somewhere what it is. RG59 doesn't work well at all with OTA signals.
If the cable run is real long you may need a pre-amp to boost the signal, how long is the cable that you're trying to use? The F-connector on some of those Antennas Direct antennas break loose very easily, check that it doesn't feel loose and wobbly, if it is, the connection inside of the junction block may be broken. That one looks like a DB4 or a DB4e maybe? Those are decent antennas for the size and price.
If your TV is newer and has a built in ATSC tuner you'll probably get much better signal with the TV's ATSC tuner than using the converter box. All of the converter boxes I've used cut the signal way down. If the TV's an older one and you can't tune ATSC with it, then you'll have to use the converter box. Most TV's made after 2008 have an ATSC tuner, even some earlier ones, Panasonic put them into their plasma TV's as early as 2006.
You can check on TvFool.com and see what stations you should be able to receive and signal strength for them. Here is the link....
http://www.tvfool.com/index.php?option=com_wrapper&Itemid=29
If you go to TvFool and post the result of the report for your area here, someone on here will be able to tell you pretty much what you should be able to receive for stations.
You could try bypassing that grounding block in one of your pictures with a splitter or double F connector just to eliminate that as a suspect. I doubt it's that but it's easy enough to do and could possibly be the culprit.