Several HD channels are not coming correctly

is your receiver an H20-600?  look for the model number inside the access card door. 

also it would help to see your signal readings.

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. If you have a DVR it's important to check BOTH satellite tuners. 

Fill in your readings for each satellite and tuner on the new post you create, using the example below as a guide. (The example below is only an example and not a form that will appear in your post unless you "cut" and "paste" it.) 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 # # # # # # # #
9-16 # # # # # # # #
17-24 # # # # # # # #
25-32 # # # # # # # #

Satellite transponders (3 total at 110º)
[A few HD channels, also beamed from 99 & 103º]
1-8 NA NA NA NA NA NA NA #
9-16 NA # NA # NA NA NA NA

Satellite transponders (11 total at 119º)
[Local SD channels for some cities, Spanish package]
17-24 NA NA NA NA NA # # #
25-32 # # # # # # # #

Satellite transponders (16 total at 99º(s)) [or 99º(b)]
[Local HD channels for some cities]
1-8 # # # # # # NA NA
9-16 NA NA NA NA NA NA # #
17-24 # # # # # # # #
[Note: these can be very slow to appear]

Satellite transponders (14 total at 99º(c)) [or 99º(a)]
[National HD channels]
1-8 # # # # # # # #
9-16 # # # # # # NA NA
[Note, these can be very slow to appear]

Satellite transponders (16 total at 103º(s)) [or 103º(a)]
[Local HD channels for some cities]
1-8 # # # # # # NA NA
9-16 NA NA NA NA NA NA # #
17-24 # # # # # # # #
[Note, these can be very slow to appear]

Satellite transponders (16 total at 103º(ca)) 
[National HD channels]
1-8 NA NA NA NA NA NA NA NA
9-16 # # # # # # # #
17-24 # # # # # # # #

Satellite transponders (14 total at 103º(cb)) [or 103º(b)]
[National HD channels]
1-8 # # # # # # # #
9-16 # # # # # # NA NA
17-24 NA NA NA NA NA NA NA NA

Satellite transponders (9 total at SWM)
[You'll only see this if you have a Single Wire Multiswitch (SWM) dish]
1-8 # # # # # # # #
9-16 # NA NA NA NA NA NA NA

my reciever is H20-100 and below are my signal readings.

101ºW
1-8       97 95 97 83 95 100 96 100
9-16     95 96 97 81 96 100 96 100
17-24   94 100 95 77 95 100 96 100
25-32   95 93 95 89 96 100 95 100

110º
1-8       N/A N/A N/A N/A N/A N/A N/A 96
9-16     N/A 97 N/A 97 N/A N/A N/A N/A
17-24   N/A N/A N/A N/A N/A N/A N/A N/A
25-32   N/A N/A N/A N/A N/A N/A N/A N/A
  
119º
1-8       N/A N/A N/A N/A N/A N/A N/A N/A
9-16     N/A N/A N/A N/A N/A N/A N/A N/A
17-24   N/A N/A N/A N/A N/A 100 95 62
25-32   0 100 100 100 0 100 0 100

99º(s)
1-8      0 35 0 0 72 86 NA NA
9-16    N/A N/A N/A N/A N/A N/A 96 77
17-24  96  95  0  84  0  0  96  97
 25-32 N/A N/A N/A N/A N/A N/A N/A N/A


99º(c)
1-8      93 95 91 95 94 94 91 94
9-16    93 94 93 95 95 95 N/A N/A
17-24  N/A N/A N/A N/A N/A N/A N/A N/A

103º(s)
1-8        8 66 63 81 0 0 N/A N/A
9-16      N/A N/A N/A N/A N/A N/A 93 94
17-24    0  0  98  97  91  95  64  82
25-32    N/A N/A N/A N/A N/A N/A N/A N/A

103º(ca)
1-8      N/A N/A N/A N/A N/A N/A N/A N/A
9-16    93  81  93  89  91  82  92  90
17-24  92  88  95  90  93  89  95  92
25-32  N/A N/A N/A N/A N/A N/A N/A N/A

103º(cb)
1-8     93  87  92  88  92  89  93  92
9-16   93 91 94 94 93 93 N/A N/A
17-24 N/A N/A N/A N/A N/A N/A N/A N/A
25-32 N/A N/A N/A N/A N/A N/A N/A N/A

hmm, those readings are great. 

are theses readings from the affected receiver?  

was this receivers having the problem when you  took these readings?

do you have any other receivers/DVR's?  

are they having the same problem, or are they working OK?

Yes they are from the affected reciever and the channels were not coming in at the time.  Actually, these channels have never come right ever since the issue started.  We do have an old, non HD receiver in another room.  Since it isn't HD, some of the channels aren't offered but the channels we do get on the old receiver come in fine.  For example, 286 comes in on my old receiver fine but not on the HD receiver. 

Is there a possibility you are using a custom guide and not getting the proper feed from the affected channels?  Try this.  Do a red button reset of the receiver.  When it comes back up, press guide -> yellow button -> change favorites list -> all channels.  Then menu -> ....setup -> system setup -> display -> preferences -> guide HD channels -> hide SD duplicates.

These two items will assure that you are getting the HD feed from the channels in question.  This may not correct your problem but it will assure that a setting is not causing your issue.  Note that if it does make a difference that any series set up prior to the changes will need to be deleted and redone.

I did both of your suggestions and they were already set to "all channels" and "hide sd duplicates" .  After checking the settings, I unhid the SD duplicates and I can view those channels in the non HD version with the affected receiver.  

Probably time to call for a service visit.  It could be a defective Receiver or BBC module.  The tech will be able to fix whatever is wrong for $50 service visit charge (free if you have DirecTV's Equipment Protection Plan). 

Thanks!