For those of you with an interest in amateur LF work, you may be interested in the upcoming WSPR test transmissions from Ron, WH2XND / NI7J, located in Phoenix, Arizona.
One of Ron's several experimental licences allows him to run as much as 10W ERP from 68-76 KHz. To generate this amount of ERP at 75 KHz requires a lot of power and I suspect that he will still be well under his licence limitations ... amateur-sized antennas are just not very efficient on these low fequencies.
Previous experiments a few years ago, at lower ERP, produced impressive results, as shown by one of the WSPRnet maps for an overnight session on 75.075 KHz.
Ron used one of the Hans Summers U3S transmitters to generate his LF WSPR signal, amplifying it with a 400W Hafler audio amplifier. This winter's tests will be at 800W, with a W1VD FET amplifier designed for VLF.
Ron's experimental licence also covers 470 - 495 KHz at a whopping 100W ERP and 130 - 140 KHz at 50W ERP ... some serious power.
You may also find Ron's interesting and well-illustrated website description of some experimental antenna work that he has been doing on MF, LF and what it takes to resonate a typical Marconi 'T' on these bands.
|MF- LF 'T' Antenna At WH2XND|
|75 KHz Loading Coils!|
Ron has tentatively chosen late November or early December for his 'almost' VLF tests and when the date and frequency are finalized, I will post the information here on the blog.