OTHR Radar Interferance on 40Mtrs

  • 🎬 Video
  • ℹ️ Description

Interferance from OTHR Radar from China on the 40mtr ham band.(heard from 7.027mhz to 7.094mhz)
Heard on Oct 19th 2006 at 1040utc.
Using a inverted vee dipole for 40mtrs and a Icom IC 7400 Radio.

💬 Comments

Interesting information to know how OTHR sounds. Thanks for share.

Author — py2zx


yes, its true! even here in the Philippines we experience such noise early in the morning when band is really open and late at night. Making 40m communication down. As far as i can remember its started early 2005 until now, even band propagation is down its still there. Is there a way we can trace this irritating noise?

Author — revadan


Any chance this was due to the Jindalee OTH radars? They would be a bit closer to your location. They switch frequencies periodically, which would explain the sudden drop in signal.

Author — tuxicle


This definitely is not an OTHR.The most important clue is the changing in the Pulse Repetition Frequency.There is no reason for a radar to change the PRF.PRF also is too high for long range radar. Usually a signal travels to the target and back to the radar, before the next pulse is emitted.To avoid jamming of returning signals.So with 1000 Hertz max. range is 150km.I did not measure the PRF with an Oscilloscope, but its more like 2000+ Hz.This is a jamming signal to prevent listening to a station

Author — wwwtotalitaerde