Yes, in ANY vertical antenna, the ground pain (body of the car, the radials you lay out on a ground mounted vertical, those parts of antennas you see sticking out parallel to the ground on rooftop antennas) are as much a part of the antenna, and are as needed as the vertical part of the vertical

Interestingly, as you start to put out more and more ground radials, your SWR will go up to a point, because a vertical doesn't have a natuaral resistance of 50 Ohms.

All this stuff is 'old hat' to hams who have studied it (not all have) It's PART of the reasons hams have been known to be able to get signals through, we tend to know the issues. Unfortunately, a lot of hams today haven't learned. Hams USED to even practice getting on organized nets for 'traffic handling' - basically how not to step on each other, and get a message through

I know very little about antennas, unfortunately. But I do know a lot of hams who practice using organized nets. I think it's more common in the HF bands than VHF/UHF bands.

I just want to add something to my earlier post in this thread (I think it was this thread--I'm old, OK?) regarding one of my FM handi-talkies that, after very little use, without warning quit receiving (transmitted OK). It was sent back in to Icom about 2 weeks ago and came back today completely fixed at no charge. So, score one point for the Icom company.

VHF/UHF nets are fairly common in larger cities, particularly for the ARES/RACES members - in NYC, it's on the 147.00 repeater on Monday nights (I have not checked-in to the net in a year+, but used to be a regular net control operator)