The most common cause of computer lockups or USB connection failing, when you key your transmitter or very shortly after the transmitter is keyed, is RF getting back into the computer through one or more of the cables connecting the radio to the computer. 

RFI can also be generated by your radio's power supply, since when transmitting, the radio draws considerably more current and even the smallest amount of RF generated by the power supply could possibly create an issue. Cables running from the radio to the computer that cross or run in very close proximity to AC Line cords can also pick up small amounts of RFI. It doesn't take much to cause issues, therefore the source of an RF problem is very difficult to troubleshoot and resolve.

A way of testing to see if this is the case is to turn your RF output from the radio down to it's lowest possible setting, then attempt a transmission. If it completes the transmission successfully, increase the RF output by about 10 watts and try again. Keep going by making transmissions, and increasing the RF output by about 10 watts each time and see if you reach a point where the transmission fails. At this point, back the RF down and to see if you can once again complete a full transmission without the lockup.

If you find the computer locks up at a certain power level, try some of the following.

1. Check ALL grounds to make sure all equipment is well grounded. Make sure equipment grounds are not "daisy chained" together. Each piece of equipment should have it's own separate grounding wire which can be run to a common grounding bar.

2. Check ALL PL-259 antenna connections to make sure they are tight. Due to heat being generated when transmitting, with the connections expanding and contracting, even the slightest bit, the connections do have a tendency to "unscrew themselves" over time.

3. Put Ferrite Beads on BOTH ends of ALL the cables running to and from the radio and computer. If you are using an interface like the SignaLink, make sure you put the beads on both cables, the one from the computer to the signalink and on the one from the signalink to the radio.

4. If running the Yaesu SCU-17 interface, replace the USB cable that came with the unit with one of better quality and has ferrite beads on both ends. The one that comes with the SCU-17 is poorly shielded and has proven to be very susceptible to even small amounts of RF.

5. If you are using a desktop computer, ensure the computer chassis is grounded. If using a laptop, which of course would be more difficult if not impossible to ground, try to keep the laptop as far as possible from the radio, tuner, radio power supply, and try to route any cables running from the radio to the computer as far from antenna feedlines, power supply cables or any AC line cords as possible.

If you try all of the above options and still have problems when transmitting, please contact us and we will try to provide more suggestions on how to resolve this issue.