The Baofeng UV-5R radios on our bikes seem absurdly sensitive to intermodulation interference, particularly on rides across the Walkway Over the Hudson, which has a glorious view of the repeaters and paging transmitters atop Illinois Mountain:
A better view of the assortment on the right:
And on the left:
Not shown: the Sheriff’s Office transmitter behind us on the left and the Vassar Brothers Hospital / MidHudson pagers on either side at eye level. There’s plenty of RFI boresighted on the Walkway.
Anyhow, none of the Baofeng squelch settings had any effect, which turned out to be a known problem. The default range VHF covered a whopping 6 dB and the UHF wasn’t much better at 18 dB, both at very low RF power levels.
We use the radios in simplex mode, generally within line of sight, so I changed the Service Settings to get really aggressive squelch:
I have no way to calibrate the new signal levels, but I’d previously cranked the squelch up to 9 (it doesn’t go any higher) and, left unchanged, the new level makes all the previous interference Go Away™. Another ride over the Walkway with the squelch set to 4 also passed in blissful silence.
If the BF-F9 levels mean anything on a UV-5R, that’s about -100 dBm, 20 dB over the previous -120 dBm at squelch = 9.
The new squelch levels may be too tight for any other use, which doesn’t matter for these radios. As of now, our rides are quiet.
[Update: Setting the squelch to 5 may be necessary for the Walkway, as we both heard a few squawks and bleeps while riding eastbound on a Monday afternoon. ]
The Smell of Molten Projects in the Morning 
No tone squelch accessories on said radios, I take it? Of course, just how much $$$ were these recalcitrant communicators? ICOM mobiles had pretty solid front-ends at one point. Not sure about the HT offerings over the years. Cheers.
You can get ’em in packs of five for $120 and one for $30, so we’re not talking “solid” anything!
The UV-5R has tone squelch / DCS / all that, but after intermod gets into the front end, it’s all over the radio.
Still true: it’s the worst HT you’d (well, I’d) be willing to use …
Interestingly, my ICOM mobile experienced the first (in a long time) IMD attack this morning. Sounded like paging, but my ear for such things is limited (do people still use pagers?!??!). Nothing to see here…move along. Move along…
Pagers are still a thing, particularly in the medical field, for reasons I cannot imagine. Perhaps carrying a device with a specific purpose is better than SMS messages on a phone; there may be a HIPAA messaging requirement, even if paging isn’t encrypted.
The intermod pacing definitely feels like pager bursts, rather than live voice transmissions.
Pagers still have vastly better coverage in the bowels of the basements of hospitals in the middle of nowhere. Actually, I miss mine…
Hadn’t thought of that: VHF (and even UHF) wipes the basement floor with 2 and 5 GHz signals!
I’m mildly amused when folks discover their phones hang up when the elevator doors close, except when there’s a cell antenna within line-of-sight outside the building.