SD Only, no HD channels.

Most likely a dish alignment issue. SD channels are beamed from the 101ºW satellite and are generally "stronger" than the HD channels beamed from 99 and 103ºW. 

What DVR/Receiver model numbers do you have?

Do they all have this issue?

Please post back with your signal readings for each satellite's transponders (and both tuners if applicable).  You'll find these readings under "Menu" -> "Setup" -> "System Setup" -> Satellite -> "View Signal Strength".  Note the "+" and "-" symbols next to the "Satellite" and "Tuner" entries where you can toggle the readings between the various satellites and both DVR tuners. 

Fill in your readings for each satellite and tuner using these examples.  A properly aligned dish will show 80-90s on most of the relevant transponders (although some will be low or zero):

Satellite transponders (32 total at 101º)

[Most of your standard definition channels are beamed from 101ºW]

1-8    x   x   x   x   x   x   x   x

9-16   x   x   x   x   x   x   x   x

17-24  x   x   x   x   x   x   x   x

25-32  x   x   x   x   x   x   x   x

Satellite transponders (11 total at 99º(ca))

[National HD channels]

1-8    NA  NA  NA  NA  NA  NA  NA  NA

9-16   x   x   x   x   x   x   x   x

17-24  x   x   x   x   x   x   x   x 

Satellite transponders (14 total at 99º(cb))

[National HD channels]

1-8    x   x   x   x   x   x   x   x

9-16   x   x   x   x   x   x   NA  NA

Satellite transponders (16 total at 103º(ca))

[National HD channels]

1-8    NA  NA  NA  NA  NA  NA  NA  NA

9-16   x   x   x   x   x   x   x   x

17-24  x   x   x   x   x   x   x   x

Satellite transponders (14 total at 103º(cb))

[National HD channels] 

1-8    x   x   x   x   x   x   x   x

9-16   x   x   x   x   x   x   NA  NA

17-24  NA  NA  NA  NA  NA  NA  NA  NA