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Author Topic: RFI from Recent Installation of Metal Rain Gutters?  (Read 777 times)

vhavrilko

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RFI from Recent Installation of Metal Rain Gutters?
« on: June 19, 2020, 2308 UTC »
I have what may sound like a silly question. I just had the siding on my house replaced, including metal rain gutters, which I never had on the house. They are aluminum (K5 gutters). I went camping when they installed them, and when I came back, I noticed that my noise level went up by two S-units. I have a magnetic loop antenna on a rotor mounted on the eve of the house (25). My loop also lost the ability to null local MW signals, too. The rotor is operational.

Would the installation of aluminum rain gutters be responsible? Short of removing them, will grounding the gutters help? I also noticed my signal level went up, too. I checked the signal of a local MW radio station about 40 air miles from here and it went up in strength by five S-units. This signal was compared to the same rotor position prior to the gutter installation. Can the rain gutters act as a parasitic antenna interfering with the loop's operation? I have not reinstalled my long wire yet, so I will see if reception is affected with this antenna.

The only other option would be to remove the metal rain gutters and install plastic gutters. Has anyone ever had issues with metal gutters in proximity to antenna systems? A search online found that they can cause problems.

Offline syfr

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #1 on: June 20, 2020, 1342 UTC »
Interesting question!

The gutters are going to act as an antenna just like any other conductor, so for sure it will affect any antenna that is nearby it.  It sounds like its coupling more RF into your mag loop just like putting a large wire in the vicinity would

It might be easier to move the antenna than to pay for the re-guttering. 
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Offline Ray Lalleu

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #2 on: June 20, 2020, 1420 UTC »
5 S-units up for a local MW station, only 2 S-units up for the noise background.
I would not call that RFI !
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Offline syfr

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #3 on: June 20, 2020, 1735 UTC »
Agree!

Turn the RF gain down a hair and you're back to where you started  :)
Kiwsdr x 2. TenTec Paragon/NRD535

Offline redhat

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #4 on: June 20, 2020, 1835 UTC »
If you are in close proximity to any strong RF fields, the 'rusty bolt' syndrome can cause that, and aluminum is particularly bad about producing oxides.  I would try relocating your loop and see if any improvement is noted.

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Offline ThaDood

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #5 on: June 20, 2020, 1850 UTC »
I've DF'ed wide-ass RFI hash to duct works inside the house and the outside vent pipe. Every time the furnace would kick on, I'd get this bad crunching noise as well. So, I grounded the whole assembly. That worked.
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vhavrilko

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #6 on: June 20, 2020, 2253 UTC »
ALCON,

Thanks for all your replies! I also contacted DX Engineering, who sells this loop, and he also told me to relocate. He wondered why I had the loop up at 25'. My noise level was always too high, e.g., S2-4. However, that is better than S5-7, which it was on some bands after the gutter installation! He recommended mounting it at least 6' above ground level. Today, I took it down from the roof and located it in the middle of the yard away from the house. I am waiting for the Quickcrete to dry. I also needed to order 100' of coax and rotor cable. I  hope to be back in business in a week or so.

V/r,
Vince

Offline pinto vortando

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #7 on: June 20, 2020, 2331 UTC »
My guess is that the aluminum gutters are acting like an antenna and re-radiating signal which affected the loop's ability to null a signal since it was now receiving signal from several directions.
Relocating the loop as you did should fix the problem.
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Offline Swan270

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #8 on: June 26, 2020, 1622 UTC »
Yes, the gutters are coupling with your loop. MOve the loop as far away from the gutters as possible.

vhavrilko

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #9 on: June 27, 2020, 1340 UTC »
I relocated my loop in the back yard. It is only 9' in height from the top of the antenna to the ground, but performance has significantly improved. The QRN is gone, and the signals did not degrade. One plus about having it in the yard is I do not have to climb the roof to service the unit. The only antennas attached to the house are an end-fed random wire into a magnetic balun (which is not affected by the rain gutters) and an NMO scanner antenna, which are low-profile. I appreciate all the comments in this thread.

Offline redhat

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Re: RFI from Recent Installation of Metal Rain Gutters?
« Reply #10 on: June 28, 2020, 1806 UTC »
I'm glad to hear there was a happy ending  ;D

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