I use a very common, simple, and fairly inexpensive solution to keying VARA FM on most any FM Radio.? ?I use a DRA-30 (other DRA models will work too) to provide the sound card function and the PTT function.? These? ~$80 "Sound cards" provide good bandwidth and separate PTT control to most FM Radios.? I have personally tried it without ANY radio modifications with the Alinco 50Watt DR-135 without any radio mods. I have also used the same setup (with the addition of a 15 pin DIN connector) on a Chinese TH-9000D with good results. Using a dedicated sound card for the application is the key to reliable operation with full VARA FM Wide bandwidth.
