The 751R is the newer version of the 751. Before the OTA digital conversion in '09, UHF channels went up to channel 69. After the conversion, UHF channels only go to 51. The 751R was re tuned to receive a higher gain on the lower UHF channels. Otherwise, the two models are identical.
I am new to AVS forums. I am using digital antenna's from 2007 and am able to get good # of channels in NJ. Originally i had a $18 antenna and was getting channels from Philly. Then i upgraded to $35 antenna from ebay and it dropped a few channels.
This week i upgraded to RCA ANT751 and i am not getting any channels. even though it is highly rated.
For all regular channels
I have signal strength in high 80's
SNR in high 20's
IF-AGC(%) above 100.