My experience is totally the opposite of yours: my digital broadcast is great. I now get 12 channels where I used to get just 4 and that includes 3 PBS stations.
Everybody's experience is different. It depends upon your location and the direction and distance of the stations from you. Check out this site:
http://www.antennaweb.org/aw/welcome.aspx and it will help you to find the right antenna by showing where your stations are located and their direction from your home and it will give you an idea of the kind of antenna needed.
From the government website about the digital transfer:
http://www.dtv.gov/consumercorner_5.html#faq5Do I Need a Special Antenna to Receive DTV Signals?
No. DTV signals do not require a special antenna. The reception of over-the-air DTV programming requires the same type of signal reception equipment (an antenna) that worked with your analog TV set.
If you needed a rooftop antenna to receive analog TV broadcasts, the same antenna generally will work to receive DTV broadcasts. It should not be necessary to purchase new antennas that are marketed “digital ready” or “HD ready.”
While you do not need a special antenna to receive DTV signals, you will need additional equipment to receive over-the-air television when the DTV Transition is completed -- if you use an analog TV set that has only an analog tuner.
Consumers who rely on antennas (including outdoor antennas and "rabbit ears") to receive over-the-air broadcast signals on analog sets with analog tuners will need to obtain separate digital-to-analog set-top converter boxes to watch over-the-air TV.
These boxes receive digital signals and convert them into analog format for display on analog sets. Analog sets connected to such converter boxes will display digital broadcasts, but not necessarily in the full, original digital quality.
For more information on antennas, see the Antenna Guide, Consumer Tips for DTV Reception on VHF TV Channels 2-13, or Indoor Antenna Consumer Advisory.
Also:
Can I Use My UHF/VHF Antenna to Receive DTV?
Yes. Television stations broadcasting in digital use both the VHF (channels 2-13) and UHF (channels 14-51) bands. Many indoor antennas use “rabbit ears” for the VHF band and a “loop” or “bow-tie” antenna for the UHF band.
• Make sure you are using an antenna that covers both the VHF and UHF bands and have connected it properly. Many antennas currently being sold as “HDTV Antennas,” perform best at receiving UHF signals; some of these models state that they provide reception of signals on channels 7-13 but actually perform less well receiving those channels. When acquiring a new antenna, be sure to talk to retail consultants and look at information on the packaging and/or the Internet to make sure that any new antenna you may choose provides good reception of both VHF and UHF channels. In addition, if you use an indoor antenna and receive signals on VHF channels, you may need to use an antenna with amplification. You can use the DTV Reception Maps on the dtv.gov website at
http://www.fcc.gov/mb/engineering/maps/ to identify the stations you should be able to receive at your location. For more information on antennas, see the Antenna Guide at
http://www.fcc.gov/cgb/consumerfacts/dtvantennas.html.