Maybe referring to this from Samsung? Won't help the stuttering.
Local HDTV broadcasters were recently required by the FCC to change the MPEG-2 Packet Identifier (PID) value at their broadcasting head end to a value above 0x0030. This change had to be made by January 1, 2005. One of the unforeseen results of this change is that in certain areas of the country, set-top-boxes from a number of manufacturers, including Samsung's SIR-TS160 and SIR-TS360, get only the video portion of local, over-the-air (OTA) high definition broadcasts but not the audio.
Samsung and Direct TV engineers are working to rectify the problem and should have a permanent solution shortly. A temporary work around for this problem has been developed. It involves removing the zip codes from primary and secondary air and then rescanning the channels.
Removing the Zip Codes
To remove the zip codes, follow these steps:
1. Turn on your TV and your set-top box.
2. Press the Menu button on your remote control.
3. Highlight Setup and press the OK button.
4. Highlight Installation and press the OK button.
5. Highlight Local Networks and press the OK button.
6. Highlight Primary Air and press the OK button.
7. Highlight Clear and press the OK button.
8. Press the Back button.
9. If you entered a Zip Code in Secondary Air, highlight Secondary Air, and press the OK button.
10. Repeat Steps 7 and 8.
11. Press the Exit button on the remote. The set-top-box will reboot.
Rescanning the Channels
To rescan the channels, follow these steps:
1. Press the MENU button on your remote control.
2. Highlight the Setup menu item, and then press the OK button.
3. Highlight the Antenna & Cable menu item, and then press the OK button.
4. Highlight the Scan Type menu item, and then press the OK button to display the list of available channel types. The Scan Type list appears.
Note: The Scan Type list lets you set your DIRECTVÂ® HD receiver to scan automatically for channels from Digital sources (off-air ATSC broadcasts), Off-Air NTSC sources (standard TV broadcasts), Cable NTSC (standard cable TV services), or all of these. If this is the first time you are setting up this DIRECTVÂ® HD Receiver to receive local channels, use the All setting. Otherwise, OK the specific Scan Type listing.
5. Highlight the Scan Type that matches the type of broadcasts you would like to program into your DIRECTVÂ® HD receiver, and then press the OK button.
6. Set your cable TV type by highlighting the Cable Type menu item and pressing OK.
7. Highlight the type of cable signal your cable TV service provides (STD, HRC, or IRC), and press the OK button.
Note: STD, HRC and IRC are signal formats used by cable TV services. Contact your Cable TV service provider to determine which signal type they use.
8. Highlight the Scan Channels menu item, and then press the OK button. The Scan Channels screen appears and the DIRECTVÂ® HD receiver automatically starts looking for all available channels of the type you specified in the Scan Type list. Wait until the scan is completed.
9. If the automatic scan included any channels that you do not intend to watch, you can edit the channel list by using the Add/Remove Channels menu item in the Antenna & Cable menu.
10. If any of the off-air antenna channels appear out-of-tune, you can fine tune them using the Fine Tune Channels item in the Antenna & Cable menu.
11. If you have added digital channels from an off-air antenna, you can check the signal strength for that channel by using the Digital Off-Air Signal Strength menu item in the Antenna & Cable menu.
12. To exit the Menu system press the EXIT button on your remote control.
Note: This work around lets you get both video and audio for the OTA channels. However, you will not be able to get the Guide Data (onscreen listing of upcoming programs) for these channels. This problem should be corrected shortly.
I had a problem with sound on one station I receive OTA and this fixed it. Later the station changed whatever at their end and I could go back and use the zipcode.