I purchased a RG-58 Coax Cable, 50ft long from the GMRS website. It was listed with the following description: "Retevis RG-58 Coax Cable 50-Ohm 50 Ft". On a separate note, I did find out that the Midland MXT 400 microphone cable is kind of weak in the connector when you pull and stretch the microphone cable. You need to make sure the cable connector is set in firmly or you will not be able to transmit. Since I'm using this radio at home I'm going to see if there is a desk top microphone that can be used with this radio and that probably will be a better solution. Midland probably should look at making the connector better. I have another MXT 400 radio on my wife's car and she told me had a similar issue if she handed the microphone to my son riding on the passenger seat.