<div dir="ltr"><div dir="ltr"><span style="color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px">Here is a December 1956 article in Popular Electronics about whistlers with a makeshift VLF antenna, mains hum filter, and preamp/amp for listening to the VLF band in 1956! You can read the article </span><a href="https://worldradiohistory.com/Archive-Poptronics/50s/56/Pop-1956-12.pdf" target="_blank" rel="nofollow noopener" style="box-sizing:border-box;color:rgb(51,122,183);text-decoration-line:none;font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px">here</a><span style="color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px"> on PDF pages 39-41.</span><br style="box-sizing:border-box;color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px"><br style="box-sizing:border-box;color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px"><span style="color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px">Jonathan</span><br style="box-sizing:border-box;color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px"><span style="color:rgb(51,51,51);font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:14px">KC3EEY</span><br></div></div>