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eHam Forums => RFI / EMI => Topic started by: KD5JFT on June 14, 2004, 12:27:11 AM



Title: VHF Noise "burst"
Post by: KD5JFT on June 14, 2004, 12:27:11 AM
Earlier today, I ran into a new problem. 6M and 2M noise levels were way down, and I could hear some good activity. It was very clear, but did not register on the S meter. I had a noise problem rear it's ugly head. Every nine seconds and lasting for between four and five seconds, I was getting noise "bursts". These would register between 5 to 7 on the S meter. Needless to say this totally blocked any attempt to make a contact. This noise was evident over the entire 6M and 2M ssb portions of the bands. I was using horizontal omni antennas (Killer 6 and Big Wheel from www.dwtulsa.com) mounted at approximately 30ft, and a Yaesu FT-847 and FT-726. The noise was there at 17:00 and stopped between 19:00 and 19:30 Central Time. The noise was not apparent on any HF bands (attic mounted G5RVjr). I switched to a vertical antenna and the noise was still there, just not as bad (3-4 on the S meter). With the vertical, I could not even hear the conversations between the "noise bursts" although I could with the horizontal antennas.
 
Has anyone seen this type of problem?
Any ideas what could cause this?
Any suggestions on tracking it down if (when) it re-occurs?
 
I tried disconnecting all the electrical equipment in the shack, and it made no difference.  This includes the Linksys WiFi AP/Router and cable modem. I can only assume that the "noise" is external to my shack. I may have a three element 2M beam up soon, but that is my only directional antenna.
 
Any ideas would be appreciated.
 
Craig
KD5JFT