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eHam Forums => Elmers => Topic started by: K1KIK on September 07, 2009, 09:51:44 AM



Title: Home outlets buzz when transmitting
Post by: K1KIK on September 07, 2009, 09:51:44 AM
Any ideas as to what might cause an electrical outlet on the other side of the house to buzz/vibrate when I transmit?  I am transmitting at 100 watts through a multi-band dipole mounted in the attic. Thanks.


Title: Home outlets buzz when transmitting
Post by: N3OX on September 07, 2009, 10:01:14 AM
I'd check the wiring and box on that outlet ASAP, because an ordinary electrical outlet should be a completely linear device incapable of turning any applied RF into sound.  Something like a GFCI on the verge of tripping would make more sense.

With an ordinary outlet, I think you'd have to have a loose connection or RF arcing of some kind, both of which need immediate attention.

One thing that comes to mind is if you happened to have a resonant length of wire, the ground wire could be arcing to the box or something, just because the ends were at high RF potential.  

What's the whole story?  What kind of outlet?  What's plugged in to the outlet?  Anything?

73
Dan


Title: Home outlets buzz when transmitting
Post by: AA4PB on September 07, 2009, 10:04:04 AM
I would guess that its a ground fault type (GFCI) in a bathroom or kitchen and that RF is being picked up by the wiring and conducted into the electronics in the GFCI. You **might** be able to replace the CFCI outlet with one of a better type. The only other solutions are to move the antenna or reduce the power output.


Title: Home outlets buzz when transmitting
Post by: W4VR on September 07, 2009, 10:45:33 AM
The solution to this problem is to mount your antenna outside and away from your house.  If you live in a neighborhood with restrictive covenants, ask for permission to install a flagpole in your backyard.  Use small gauge wire that your neighbors won't see and pass your coax up the flagpole.


Title: Home outlets buzz when transmitting
Post by: N7ZM on September 07, 2009, 11:17:05 AM
I had the same happen here because of inadequate grounding. It was a GFCI on the verge of tripping because if RFI getting into wiring. Fixed the grounding at my outside breaker box and the problem went away. The GFCI was located in my laundry room and the buzzing sounds were only on 80 meters when I ran my Alpha.


Title: Home outlets buzz when transmitting
Post by: K1KIK on September 07, 2009, 01:57:49 PM
Well, my buzzing outlet IS a GFCI outlet, so I guess that I will begin by checking my grounding.  My HOA won't even allow a flagpole in the back yard. Thanks for the replies.


Title: Home outlets buzz when transmitting
Post by: K8AC on September 07, 2009, 01:58:34 PM
If your home was built in the 1970s when they were using aluminum wire, the problem is likely a loose oxidized connection between the wire and the outlet screw.  The screw may have been tight when the outlet was installed, but the aluminum wire tended to "relax" over time, leading to a slightly loose screw and oxidation on the aluminum conductor.  Quite a few houses in this part of NC went up in smoke during the 20 years after they were built with aluminum wire.  I recall tightening up quite a few outlet screws at neighbors houses back in the mid 1970s, when the outlets were making noises as you describe.


Title: Home outlets buzz when transmitting
Post by: AA4PB on September 07, 2009, 02:09:03 PM
Older GFCIs were more sensitive to false tripping than the newer ones. You may find that simply replacing the GFCI with an upgraded unit will solve the problem.


Title: Home outlets buzz when transmitting
Post by: K7STO on September 07, 2009, 02:16:43 PM
You could start first by replace the old GFCI with a new one. The current generation of GFCI's are less prone to RF interfence and I would second the idea of relocating your antenna outside.
73
Mike
KB7STO


Title: Home outlets buzz when transmitting
Post by: K7RNV on September 07, 2009, 04:50:18 PM
Hello from Reno Nv.. I had the same problem, with gfi and regular plugs, the new house i live in was done with very poor quality plugs, I replaced all plugs and gfi plugs with top quality ones and on the gfi ones i put a terrord snap on coil on the hot side and my problem is gone gone gone....It took awaile to pin it down, but when i tried and replaced the bad junk i think the builder got 100 of them for 1 buck each hi hi.. good luck..73 bob K7RNV


Title: Home outlets buzz when transmitting
Post by: N5LRZ on September 07, 2009, 06:27:14 PM
Re CPE...
 
re your post..." I am transmitting at 100 watts through a multi-band dipole mounted in the attic. Thanks. "

Your electrical wires are running in your attic.

Your antenna is in your attic.

Your antenna is quite easily within close proximity to the electrical wires thus inserting your radio signal into the electrical wires.  And probably, every buzz and click from every appliance in your house is getting into your antenna.

Solution dont use an attic antenna


Title: Home outlets buzz when transmitting
Post by: K7RNV on September 07, 2009, 10:41:10 PM
Try a screwdriver antenna mine works great and i have it hide with plants..........


Title: Home outlets buzz when transmitting
Post by: K1KIK on September 08, 2009, 02:10:29 AM
OK.  I'll see about replacing the GFCI outlets and look into some type of "stealth" antenna.


Title: Home outlets buzz when transmitting
Post by: KH6AQ on September 08, 2009, 06:29:17 AM
The GFI outlet you need is made by Bryant. Google Bryant GFI RFI.

I replaced my buzzing GFI outlets with this and fixed the problem.


Title: Home outlets buzz when transmitting
Post by: W8JI on September 08, 2009, 07:42:53 AM
The problem you have are the GFI outlets are sensitive to RF.

It is NOT a grounding problem. There is no reason at all to even need an RF ground in the house. A lightning and safety ground at the cable entrance is needed, but RF in the house virtually always comes from the antenna system.

Since your antenna is in the attic, that is how RF is getting into the wiring. The fact it is inside the attic isn't even the real issue. It is just too close to the wires. If it was outside the wall, but the same distance away, you would have the same problem.

Change the outlets or move the antenna a much larger physical distance away from the house wiring.

73 Tom


Title: Home outlets buzz when transmitting
Post by: N5LRZ on September 08, 2009, 08:56:00 AM
Even if a ground fault outlet does not buzzzzzzz, does not all the RFI from electrical appliances still not enter the radio antenna causing RFI on receive?  And IF yes does this also not make the attic dipole a non option?


Title: Home outlets buzz when transmitting
Post by: AA4PB on September 08, 2009, 10:06:19 AM
It depends entirely on the situation. I once had an attic antenna (a full sized 40M dipole) inside an apartment complex attic (with the owner's permission) and it worked pretty well. I didn't have any significant RFI issues either way. So it all depends on the attic and how the electrical wiring is run. Moving it outside probably won't help unless you get it farther away - it's the distance that matters rather than the inside vs. outside issue (unless you have a metal roof).


Title: Home outlets buzz when transmitting
Post by: W0FM on September 08, 2009, 10:33:53 AM
Chalk this reply up as a "me too".  I had the same problem with a cheap GCFI that the builder installed.  I replaced all my GCFI's with Leviton devices.  A bit more money than some of the home improvement store brands, but worth it for me.  (And I like the little green LED on the Leviton outlets.  Easy to see it's on)

73,

Terry, WØFM