Tuesday, February 17, 2015

30 MHz Mystery Deepens

A few days ago, a very strong beeping noise appeared around 30000.99 kHz.  A previous post to this blog and a YouTube video mentioned this beep.  Others had discovered it as well, and as of today there had been loggings from Europe, both Americas, New Zealand, and possibly other places..  The signal is skip, probably from the USA, and definitely using high effective radiated power.

Or at least it was, since no one heard it today much after 1400 UTC.

This might or might not have been due to conditions.  Today's band conditions have been erratic at best and poor at worst, due to a weak magnetic storm which is still in progress.  Yesterday, however, the conditions were good.  The list of signals monitored just above 30 MHz was bizarre:

1. Everyone heard the aforementioned pip/ dasher/ beacon/ beeper/ whatever you call it at your house.

2. Europeans copied faxes from GYA, the UK Royal Navy.  This fax was heard weakly here in Southern California, although no clear copy was possible.

3. Americans and some Europeans copied USB ALE from EN10, which has been monitored before on lower frequencies.  It's the Arkansas National Guard.  Most of the time, tuning a dial/window to 30000.03 kHz centers the signal, though in the morning (U.S. time) it seems to drift up to 30000.47 kHz.  It sounds every half hour, and each sounding consists of three separate transmissions.

4. Some Europeans heard weak time or data signals.  These are not the same as the beeper, which actually has a period around 0.6 seconds.

5. Both Richard Dillman (San Francisco) and myself (SoCal) have heard single dahs, just a transmitter keyed once on and off, and then gone.  These appear rarely, like only a couple of times a day, but they are extremely strong when they do.  There is a huge click on both make and break of a sort caused more by FFT overloading than any defect in the actual transmitted signal.  Whoever is making these is using serious RF.

6.  There have been other assorted noises of a sort common to this part of the radio spectrum. Today I had what sounded like an RF welder or heater, and something which sounded like CB or "freeband" splatter.  These noises come and go with the skip, but they are nothing new.

In previous solar peaks, the spectrum between 30 and 50 MHz has produced some of the strangest things anyone has ever heard on the radio.  This time around, however, the reduced use of this band has definitely taken its toll, and I was beginning to wonder if there would be any good heavy-duty mysteries to remember in the low solar years.

I need wonder no more.  We have a good one indeed.