Thanks for all the input. Here is my update.
I now have tried two high-end directional antennas (well-known brands) that include the high-VHF band and claim to be purposed for just that band. The results are lackluster, at best. Both antennas have been used with and without an amplifier and pointed (using a compass) to the Baltimore Hearst candelabara and to the south to the channels 7 & 9 towers. The best I got was 9 for a couple of minutes before it died and just could hold the signal.
The Baltimore test got me good reception on real-channel 27 (WMAR 2.1 ABC) but that is UHF. Channels 11 and 12 (Baltimore 13.1 and 11.1, respectively) failed completely.
Bottom line: Anything that is UHF in this market I can pick up with no issue. All of the antenna input is being fed into CDVR via an HDHomeRun box. Testing has been done with direct feeds from the antenna to the TV antenna input, set to Antenna, and scanned each time.
Right now, I can stream the ABC and CBS content via their apps but this does nothing for being able to record content on CDVR.
I spoke with my engineering friend who has an inexpensive antenna. He has a clear shot of DC and Baltimore and is able to receive channels from both markets, including the channels I cannot. I was at his place over the weekend and we went through all this. He had actually met on Friday with a group of retired broadcast engineers who worked this market for decades. All of them concluded I had done what I can do and I am SOL unless I can get an elevated antenna, clear of the obstructions. I have to concur based upon my tests and observation of other installations.
I have a question. Can anyone answer this?
HDHomeRun looks easy enough to setup from a LAN perspective. My engineer friend offered to allow me to erect an antenna on his property and feed it to an HDHomeRun box that would be placed on his LAN. I could then access that with some protocols that should not be too difficult to setup. Has anyone done this with any success? We both have very good internet connections. It appears CDVR permits the connection to an HDHomeRun unit via an IP address, so that is promising. That said, would it work?
Does anyone have any thoughts on this approach? Yes, it sounds like I am creating my own mini-Locast system.