Cool yeah, I was wondering about about that, how close the measurement and how much of an SWR reading change it would mean, sounds like fractions of a millimeter can still change the SWR significantly?
Anyway, yeah the problem is ... making or buying... a UHF SWR meter. From what I've seen on the web, sounds like most "CB" SWR meters just won't do UHF, and, well, UHF ones are not cheap. I did see some ideas to use a 11m SWR meter and sort of jury rig it to work at 2m, but not sure if I can keep going to 70cm.
In lieu of all that, I was just seeing what I can collect from the protection circuit in the TK-810L. After staring at the protection circuitry, and at least sort of comparing it to the design in a 11m SWR meter - gosh darn it, they looks uncannily similar - it IS a SWR meter inside the transceiver, used to protect the output in case someone hooks up or neglects to connect an antenna! However, I don't get a SWR number like what people normally get, I get a voltage that I'd need to translate to a SWR number... or don't bother with the SWR number and simply try to minimize the voltage which is equivalent of minimizing SWR.
I was listening in on 446.000 simplex and heard nary a peep on it, so I ID'ed and said test when doing the experiments (mainly because the LMRS radio is a PITA to program, have to pull the eeprom to program new frequencies), quickly picking up the voltage from the protection circuit before I unkeyed. Initially I started testing with 2W and 10W but found that I probably got what I needed at 2W, so discontinued the 10W tests. Nobody responded to any of the tests, so I guess it's okay (if a tree falls and nobody is around to hear it, did it ... fall?)
So that last antenna experiment I got the lowest voltage. I switched over and was able to open a channel with the local ARC repeater and apparently held onto it just fine. Seems like people heard the transmission fine! However they commented my audio was weak, kind of figures, had to hack a microphone for the radio too as I didn't get one with the TK-810L. But that's a different problem. Partial success I suppose! Just need to see if I can improve it some more, and find a solution for my car as well
On the other hand, either my scanner sucks or my LMRS radio is causing intermod with the scanner. The LMRS radio seems to break squelch on the scanner if the receive tuner matches up with the tuning on the scanner somehow. Again, an unrelated (or maybe "too-close") problem but not quite on topic...