The source of widespread interference to 6 meters has been traced to a recently upgraded Wind Profiler Radar (WPR) operated by NASA at the Kennedy Space Center (KSC). The center frequency is 49.25 MHz but the emissions extend well above 50 MHz.

Once a good set of beam headings was available that indicated the source was in Florida, on Wednesday I tracked down the phone number for the spectrum manager at KSC, Steve Schindler, who happens to be NA4SA. Steve confirmed that the WPR was causing the interference, and since the amateur service is primary at 50-54 MHz and the WPR is only permitted to operate on a non-interference basis in that band Steve arranged for the WPR to be shut down. That was the cause of much rejoicing in the six meter community.

However, that’s not the end of the story; it’s more like the beginning. The WPR has a rather important mission: monitoring upper-air wind conditions prior to a launch. There is a SpaceX ISS resupply launch scheduled for the end of next week, and WPR operation will be required for about a 24-hour period prior to scheduled launch. It is unlikely that any steps can be taken to mitigate the interference between now and then. Steve advises that they will be prepared to run tests soon after the July 4 holiday to determine the best way forward, i.e. to eliminate the interference while still being able to perform the mission. He has asked the ARRL to coordinate amateur reports during those tests. The interference reports I have seen thus far have involved sporadic-E propagation, and while those would continue to be useful we will also need reports from observers within groundwave range of KSC where signal levels will be more stable. Doug Rehman tells me there are several local stations that should be able to help.

73,

Dave K1ZZ