CB antenna - single or dual stick?

[Dick Renaud]

ree,
I have been gone working on a case.

The high SWR is to be expected with the antenna folded down. The radiation pattern of an antenna is supposed to be a figure 8 if the antenna is in proper relation to the ground plane (roof) assuming it is centered on the roof. With the off center mount it will be a lop sided figure 8 with directional characteristics toward the vehicle body mass. If the antenna is moved toward the back the lobe will radiate toward the front passenger side. In reality the pattern of the stick type mobile antenna is more circular with a bulge toward the dominant body mass of the vehicle. When you lay the antenna down most of the pattern goes into the roof with some reflection. You can get some very limited short range transmit and receive. As far as damage to the radio, the final transistors may experience damage if you transmit for long periods of time, but CB radios are very low power (less than 4 watts out for 5 watts into the final) so damage may or may not occure. Never use a linear amplifier with that SWR. Not only is it illegal, but it could cause major damage to the linear. The only antenna that will operate in a down position with any acceptable SWR is a full length whip mounted on a ball and spring tied down to the gutter with an insulated clip. This type of antenna still needs a tuner between the radio and the antenna to have acceptable SWR.
All HAMS and Military communications on vehicles that tie down the antenna use tuners. CBers have gotten away with no tuner because of low power, but have SWR of 3:1 to 5:1 or greater.