Naval Research Lab report in response to ITU 2-30 MHz frequency sharing request

[W3GMS]

Interesting report dealing with potential 2-30 MHz and VHF spectrum interference from HF Oceanographic Radar.

Joe, W3GMS

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA536351

[AJ1G]

Interesting report..just starting to get into it..

In Figure 1, I would think that many of the "other users" in the spectragram are in fact EMI present from the "noisy urban environment".  Many of the lines appear to be continuous discrete signals that show no indication of modulation of any sort.

[Jim WB5WPA]

I think I can see maybe an SSB operator between the 2 and 3, and maybe a couple of keyed emissions to the right of the 4 ... slowly fading RTTY is going to be hard to differentiate from local 'birdies' though ...

Added: For a comparison, Figure 5 encompasses 40 Meters, and note a few signals appearing in what would be the CW and Phone portions of the band. The broadcasters show up strong.

(Figure 5 is spectrum from 7 to 9 MHz, so I divided the figure into 4 parts with the furthest most left part being 7.0 to 7.5 MHz.)

[WA1GFZ]

The question is What is the purpose of this system. It reads like a distributed HF OTH system.

[Jim WB5WPA]

Ocean wave RADAR

Added: Maybe DHS is going to track 'bales' as they drift discarded from 'cigarette boats' on the world's oceans?

[Steve - K4HX]

These radars have been around for quite a while. I can hear them sometimes given that I'm about 50-60 miles from the ocean.

I recorded the spectrum below in April of 2005. The sweeping signals around 4.7-4.8 MHz were likely the wave radars.

[flintstone mop]

There is something that has a formidable signal level that 'drifts through' QSOs on 40M.

[Jim WB5WPA]

Recorded in the back yard in Texas (DFW) near 4930 kHz last year with 'just a loop' antenna; yeah, that's not going to bother 'users' on the band. Uh-huh.

http://www.youtube.com/watch?v=c-T4rTBwpJA