Anyone with an Android smartphone should be able to download an audio spectrum analyzer app to detect various sonic events. Further, I believe that USB-connected SDR's (Software-Defined Radios) which can implement cheap spectrum analyzers are cheaply available. https://www.walmart.com/ip/100KHz-1-7GHz-Full-Band-UV-HF-RTL-SDR-USB-Tuner-Receiver-DIY-Kits-U-V-Antenna/199714416?wmlspartner=wlpa&selectedSellerId=101003580&adid=22222222227288811307&wl0=&wl1=g&wl2=c&wl3=346828962873&wl4=pla-735633419885&wl5=9061079&wl6=&wl7=&wl8=&wl9=pla&wl10=133212149&wl11=online&wl12=199714416&wl13=&veh=sem&gclid=CjwKCAjwwtTmBRBqEiwA-b6c_w-ZuOpEfxEMZEimG4CIU2EsgC9O5wjNx0OPs5kj_0jI-f1bA3TJQ8hoCwCAQAvD_BwE $25.31, in kit form.Although, this specific one is limited to 100Khz-1 GHz. Anything reasonably usable to go to at least 3 GHz. Jim Bell BY BOB SALSBERG, Associated Press BOSTON (AP) — A U.S. diplomat who said he suffered headaches and memory loss under mysterious circumstances while stationed in China pledged Friday to donate his brain to head injury researchers. Mark Lenzi, 44, is an unusual addition to the several thousand others, including many former NFL players who suffered concussions during their careers, who previously signed agreements to have their brains studied after they die by the CTE Center at Boston University. A security engineer for the U.S. State Department, Lenzi was among a number of diplomats who were brought home last year from the U.S. Consulate in Guangzhou, China, after reporting as-yet-unexplained symptoms. The State Department has drawn no link between those diplomats and 26 workers at the U.S. Embassy in Cuba who were withdrawn in 2017 after reporting symptoms, including those consistent with minor traumatic brain injury, or concussion. "The engineer in me wants to get to the bottom of this type of concussion and exactly what happened to me," Lenzi said while signing the pledge in Boston with representatives of the Concussion Legacy Foundation, an organization that collaborates with the BU researchers by recruiting donors and publicizing the dangers associated with head trauma. Chris Nowinski, co-founder and chief executive of the foundation, said the brain injury community must continue research to find answers for head trauma. "There are patients out there that need answers from the scientific community," he said. Lenzi now works at a State Department passport office in his native New Hampshire. He said he and his wife began hearing strange noises in their apartment in 2017, and later developed symptoms consistent with concussion. In an interview with the AP, he said he initially did not associate the noises with the symptoms, believing the headaches may have been triggered by smog. Lenzi has not been identified by U.S. officials as someone suffering from injuries similar to those suffered by diplomats in Cuba. The State Department said Friday that out of 15 diplomats or family members from China who underwent additional medical evaluation in the U.S., 14 were found not to have symptoms like those from Cuba and the other case had not been determined. [end of partial quote]