The -1713S is the SMA connector version of the - 1713.5 " radiator is similar to the longer -1715S except for gain on 440 MHz. wave on 440 and efficient loaded wave on 2 Meters. Both antennas are factory tuned for lowest SWR. Have Hi-Q, low loss construction to give maximum radiated power. Great for portable, mobile and rugged hamfest use.