Recent install on HDTV

[nhl66pens]

I searched this forum to try to not repeat previous questions so if there is a detailed explanation please just post the link to the other discussion. I just bought an DirecTV HD receiver and the antenna. I live in Baltimore and the guys that did the install were great. They set us up to receive the Washington and Baltimore local channels. When I use the online Guide, I see a lineup showing something like this:
BA-2
BA-2 AIR
WRC 4
WA 5
WA 5 - DTL 1
WA 5 - DTL 2
WA 7 AIR
WA 7 DTL 1
WA 7 DTL 2
WA 9 AIR
WA 9 DTL 1
WA 9 DTL 2
BA 11
BA 11 AIR
BA 13
BA 13 AIR.
I noticed that the DTL 1 stations in Washington are all HD broadcasts. Why don't the Baltimore stations show the HD broadcasts? Is this a problem when the install was done or do they not broadcast the Baltimore channels? If the channels exist would my receiver automatically pick them up? The NBC channels in both Baltimore and Washington do not have an HD feed and I read other posts about NBC adding a universal channel similar to the CBS ones on channel 81 and 82. Thanks to anyone that can provide some insight to my question.

 

[lowjeep]

Go to antennaweb.org and submit your address info. This will tell you all stations in your area you should be able to recieve OTA and which ones are digital. It will also tell you where transmitter towers are located in reference to your address and give you the color code for the antenna strength you would need to pick up each station.