I made some measurements to compare the gain of my channel 3 folded dipole to the gain of the PET10-8110 FM Dipole on a channel 3 analog signal.
I don't have any VHF-Low transmitters in my area and I don't have an 8VSB modulator. i used the channel 3 output of a Channel Master 7004 converter box as a test signal and measured the strength of the video carrier with my Sadelco signal level meter.
I set up one of my channel 3 folded dipoles and connected it to the output of the 7004. Then, I setup another one of my channel 3 folded dipoles about 8 feet away and measured the strength of the received signal. It was +14 dBmV (-35 dBm).
Next, I substituted the PET10-8110 FM Dipole as the receiving antenna. The received signal measured +2.5 dBmV (-46.5 dBm).
My channel 3 folded dipole has 11.5 dB more gain than the PET10-8110 FM Dipole on channel 3. I don't know how much difference that would make at your location as far as being able to receive 2 and 4.
I inspected the center and end connections of the PET10-8110 FM Dipole.
The solid copper wire for the PET FM Dipole is very thin and fragile. Usually, the twin lead wires of a folded dipole are twisted together and then soldered for greater strength. The wires of the PET FM Dipole were just touched together and then soldered.
Besides making the PET dipole fragile, the thin wires reduce the effective bandwidth, making it more difficult to cover from 2 to 4.
If you have any doubts about the wires in your PET FM dipole, you can check for continuity with an inexpensive ohmmeter like the Elenco M-1000 DMM.
or the GB GMT-318 analog meter.
My PET FM Dipole measured about 8 ohms between the two terminals that connect to the balun.