Adding a mic jack to the FT-857

Are you also annoyed with modular 8P8C/RJ type of connectors in HF Radios? Why don’t manufacturers realize their stock mike sucks and we want to connect something else. Make it easy!

I use a Yaesu FT-857 for my travel, the minimalistic size makes it the perfect travel partner. But I want to use my headset, not the stock mic. And my heil headset comes with 3.5 mm plugs and require an adapter to connect it to the RJ45 female connector hidden behind the front panel of the FT-857.

An adapter is one more part that can be forgotten at home or that can break in the field. I decided to throw my adapter away and install a “fixed adapter” for connecting the headset mic and a foot switch (or PTT).

FT-857 fitted with mic and PTT input jacks.

The connectors are held together by electrical tape and secured to chassis using a cable strap trough the vent holes just behind the front panel on down side of the radio.

Close-up of mic and PTT input jacks on the 857.

The connector are positioned so that the bracket can fold back to its original position. Cables are routed between the feet and the connectors to hold it in place, then through the hole for the mic cable. I have used factory made cables with molded connector which will last longer.

In the other end an 8P8C Modular connector has been crimped on to the cables. Its a little tricky to crimp those cables, especially the thin shields as they tend to “spread out” and make a short to with the adjacent pin. Careful positioning of the cables help, but it might also be a good idea to remove the unused pins directly adjacent to the shields.