Got CODAR?
Author: Brandon
I know all tropical band DXers have heard the ever-present CODAR nuisance that has been interfering with licensed shortwave broadcasters on the 60 meter broadcast band and below….. but have you ever seen it? Here is a 500 kHz bandwidth FFT waterfall taken with the RFSpace SDR-14 receiver, displaying from 4,500 kHz to 5,000 kHz as received here in Memphis at 0200 UTC on August 5, 2007.
Click on the image to open a larger version with more detail.
There are 4 CODAR sweepers in 60 meter broadcast band, each with a bandwidth of approximately 30 kHz: 4785 – 4830 kHz, 4875 – 4905 kHz, 4910 – 4940 kHz and 4965 – 4995 kHz, a full 120+ kHz of bandwidth that CODAR has practically destroyed. The weakest sweeper at this QTH is the 4875 – 4905 kHz, but not that it matters very much. Even weak CODAR is insanely strong. There is another CODAR sweeper between 4520 – 4550 kHz with an unique diamond-patterned signature that I have dubbed the “rattlesnake”.
Feel free to register complaints to CODAR Ocean Sensors company headquarters at info@codar.com.
Posted in General
I get what I think is severe CODAR RFI at times, more or less anywhere on the HF bands between 2-25Mhz, very strong just below 10Mhz. The repetition rate of the signal is exactly 85 times per minute.
I found your page when doing a search for information about the noise, also a description of the sound by Glen Hauser on his DX reports page, and a sound clip on an RFI sounds website which sounds exactly like what I hear except it’s at 60 beats per minute.
I have some recorded some clips of the sound in .wav format. Would you be willing to to listen to one and let me know if it is indeed CODAR radar?
I live in Berkeley Calif. near the Berkeley Marina, I’ve found website details from UCB etc which indicate that a CODAR transmitter/receiver installation has been constructed at the Marina, I don’t as yet know if this is the source for the RFI. Anything I’ve read on the web does not indicate that the radar signal would be heard over such a wide range of frequencies?
Thank you.
Colman Ahern.
Berkeley.