RG174 Extension Cable With SMA Connectors

[JASII]

I bought a SpectrumForce Wideband Antenna with Mag Mount and SMA https://www.scannermaster.com/SpectrumForce_Wideband_Antenna_with_SMA_p/01-541327.htm As luck would have it, it only has 12 feet of RG-174 coax with SMA connector attached, but my installations will require a few more feet. Can anybody suggest a place that has a short length of RG-174 coax with SMA connectors already installed on it? I was going to get one from my local MicroCenter, but it turns out that the SMA connectors in the computer file are Reverse Polarity and NOT compatible with the Uniden Home Patrol HP-1.