Wideband VHF antenna Problem at 159 MHz

[AL7OC]

On all of my XTS3Ks, I have a problem with the low battery indicator flashing when I transmit on our new EMS frequencies in between 159.03 and 159.21 with the wideband VHF helical antenna. It only happens in this frequency range, and it doesn't happen when I used a standard helical VHF antenna tuned for 147-163.

Anyone know of issues using the wideband Motorola antennas in the 159 MHz range? I prefer to use the wideband antenna as it covers the ham repeaters, SAR, and EMS channels.

Thanks!

[RFguy]

Are you using IMPRES batteries? Is the center pin of the battery connector on the battery (the one that attaches to the radio) insulated? What version of firmware is in the radio?

[AL7OC]

The radios have the last version of XTS3K ROS and DSP. The center pin isn't insulated. The batteries are non-Impres NTN4006 Ni-MH. I suspect that the SWR might be a little high at that frequency and that I am getting a little RF on the battery sense line. The question is whether the antenna might be a lousy match at that frequency, and if I am going to trash the RF amp eventually. The crappy Thales narrowband antenna that I substituted didn't cause the same problem.

If I insulate the battery sense line, it will cure the low battery false sense, but not the stray RF issue.

Thanks!