PA141

I suspect overload or mixing from an FM broadcast transmitter(s) and another signal(s). Could also be some sort of wireless TV or headphone extender if only copied over a small distance. There is so much stuff coming out of China it is impossible to keep track. Inadequate filtering in budget radio receivers will allow many spurious signals to be received. External filtering may eliminate the issue if this is the case. DTV signals would not be detected by an FM receiver as clear voice. There are very little (or maybe no) remaining analog TV stations left in the US. Those that may remain are low power translators to the best of my knowledge. Some cable TV stations may still be transmitting analog signals to customers still using analog TV receivers and leakage from cable systems falls on top of a wide frequency range (7 to 1000 MHz). CATV 64 is in the GMRS frequency range. If the local cable company is sending analog on those frequencies and has leaky cable lines it could be detected with an FM receiver.

You did not mention anything about your radio/antenna. Raising your antenna if possible should increase your range. This is the best bang for your buck improvement. Make sure you use a decent coaxial cable such as LMR400, otherwise the improvement in height could be offset by the loss with a longer cable of a smaller diameter or unknown quality. Make some noise and see if you can get a response. I suspect during commute time would be the highest chance of finding someone who is also just scanning like you. If everyone is just listening, making a contact is not likely

If you want to get on 10/15/20M, you could install just the driven element of that Yagi as a (rotatable) dipole. You will probably have to adjust the tube lengths to re-tune the element. If the match is not close enough to 50 ohms, some impedance matching may be needed. It will likely have a decent match with slight dimensional adjustments if the antenna was functional when removed. A dipole at 1/2 wavelength or more is a decent performer and a "flat" dipole will typically outperform an inverted V at the same center height.

Steve, I know people that swear by epoxied in anchor bolts (as in installing a different tower on an existing concrete base). Depending on the quality of the anchor rock, that might be viable. You might want to sign up to the TowerTalk email reflector, http://lists.contesting.com/mailman/listinfo/Towertalk and pose your question there. I know that towers anchored in rock have been discussed before. Not sure what kind of antenna you are planning, but some of those BX towers also had limitations on boom length (something like 10 feet) due to torque limitations on the tower.

Sporadic E, "E skip or Es" is fairly rare at 144 MHz but several instances are documented every year in the ham community. There are rare instances where Es has reached up to 222 MHz. I am not aware of any openings in the 440 MHz range so I would consider this propagation mode unlikely on GMRS. Es happens primarily in summer (late May to mid August). Tropospheric ducting or "tropo" is fairly common east of the Rockies, mostly in the summer through fall. Below is a current map of propagation links from automated data stations in the 144 MHz band, https://vhf.dxview.org/. These stations would be typical in power to GMRS, but at VHF. Paths in red may be usable at GMRS. Tropo commonly is usable above 440 MHz and even well into the GHz range with enhanced conditions. Tropo can cover a few hundred to 1000 miles plus and is documented at over 2500 miles. Here is a tropo propagation prediction map that shows strong potential paths in many areas of the eastern US last Tuesday. It does show a gap between MI/LA but it is only a modeled prediction based on weather patterns and at a specific time (1200 UTC). A path could develop as the weather changed through the day. These Hepburn, https://dxinfocentre.com/tropo.html maps are used by hams and other listening enthusiasts to find long haul propagation. Another way to find enhanced propagation is to listen to empty FM broadcast and NOAA weather channels in your area.

I did some data mining of the FCC daily reports a while back and it seems that they did not issue GMRS licenses with numbers less than 200 during that couple of months that I looked at. If that number block is reserved (commercial licenses maybe?) then those two will not be issued for GMRS. If anyone is trying to time the system, they were typically taking 2-4 days to rotate to the next letter sequence. They also seemed to skip WRWO completely for some reason.