[Elecraft] Strange digital transmissions

[Phil Kane]

On Tue, 25 Dec 2007 22:26:42 -0800, Vic K2VCO wrote:

> I've been hearing this lately on the low end of the 20m CW band.
> A noise that sounds like a distant machine gun. There's a burst a
> few seconds long, and then a response -- obviously from another
> station.

> These signals are wide-ish, taking up a few kHz. The K3 DSP noise
> blanker reduces their amplitude a little but doesn't eliminate
> them.

> I'm pretty sure they are not amateur signals -- they are not on
> 'digital' frequencies, they are in fact too wide to be legal in
> the CW/digital part of the band, and they are very loud.

> Does anybody know what they are?

  Most probably "your taxpayer dollars at work".  There have been
  several "Experimental" licenses issued to government communication
  systems contractors valid for any HF frequency that the contractor
  may pick, and no attempts are made to keep them off the ham bands.
  Burst-type transmissions are some of their favorite modes.

  Then again we don't know if they are originating in the US, and
  if they are originating from "certain places" in the US nobody
  involved will be willing to admit it anyhow.

  In "the good old days" I could have had my counterparts on the
  FCC HFDF monitoring net determine what and where it is, but
  alas most of them (including myself) have retired and now that
  the HFDF net is under the Public Safety and Homeland Security
  Bureau rather than the Enforcement Bureau, those who are left
  are wary of doing such favors for the "retirees".

  What freq. / time do you hear it?  I'll give a listen here.
  You may also want to check with the ARRL Intruder Watch folks.
  They may already have the answer.

--
   73 de K2ASP - Phil Kane
   Elecraft K2/100   s/n 5402