Need help with weird issue

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I think I've told this story before but I am still stumped.

Station is as follows:
Icom IC-7100
LTG AT1000 Pro II tuner
80m OCF dipole about 40 feet up
50 feet LMR400 feed line going to a lightning arrester on the house.
10 feet of LMR400 from the arrester to the tuner. 3 feet LMR400 to radio from tuner
PowerWerx 25Amp switching power supply plugged into standard 110v outlet via a power strip.
All gear is tied to a ground bus on my bench which is in turn connected to a ground bus on the side of the house which is tied to the ground rod buried next to the house. I've verified continuity of the ground as best as possible. Can't really verify continuity between the buses because of the length of the cable run...but I'm pretty sure it is fine.

The grounding has resolved an RF issue I was having with my amplifier effing with my radio's settings. The amp is not in play here as the problem predates the addition of the amp.

House
100 Amp panel with a sub-panel for the ACs (2 units - Air handler/compressor). Air Handler is 110v and compressor is 240v. York brand units.

When I operate down on 80m, say at 3570khz or 3576khz and transmit at 100W, a couple things happen:
1. Lights throughout the house flicker slightly while transmitting
2. The air handlers cycle up and run the fan for about a minute.

I'm assuming I need some type of choke to eliminate the RF affecting the air handlers, but I'll be damned if I can think of a place to put them as they are hard wired into the panels.

Is choking the correct path forward?

Thanks
 
I don't have any advice to offer on the RF choke.

Just some observations from a non Ham person, the ground rod that your gear in connected to, is that the same ground as your electrical panel? A difference in potential between two grounds can cause weird issues. You have a 25 amp power supply on a power strip plugged into a standard outlet. Most outlets and breakers are rated at 15-20 amps. Do you have a way of measuring what you are drawing through the outlet and power strip? Is that a dedicated circuit or is it shared with other parts of the house?

Reading another site about a similar issue with a York unit, several had a loose connection in the fan relay causing the fan to get power when it was off. The fan would cycle on when it shouldn't or not run when it should. http://hvac-talk.com/vbb/showthread.php?80597-air-handler-problem/page2 A loose connection could potentially be bridged when transmitting.
 
This site http://www.w8ji.com/station_ground.htm has some good information about grounding and RF interference.

Regarding the power supply, it is most likely 25A continuous 12V DC output. Input is probably ~6A 120V AC.

Yep...the power supply is a 12VDC supply for the radio equipment.

The comments about the ground is interesting. I also sent this scenario to W1ZR (The Doctor).

Here is his commentary on it.

Interesting problem. Often flickering lights indicates a common ac circuit that is noticing the effects of increasing current drain. This can often be cured by having a dedicated circuit for the radio equipment all the way back to the circuit breaker box that doesn't feed anything else. You could try just changing the circuits that the radio and the lights are tied to,

The air conditioner problem is likely due to pickup on the control wiring from the thermostats to the control system. Often multiple turns of the control wires on a type 31 ferrite toroid near the control systems(s) will help.

Also. you ground rod should be bonded to the ground at your circuit breaker box -- preferably by heavy bare wire buried outside. This will avoid potential between your utility and radio grounds during a lightning event, and might even help the problems you are having.

I am copying ARRL Lab RFI Engr Mike Gruber, in case he has any thoughts.

GL & 73, Joel

Joel R. Hallas, W1ZR

Contributing Editor, QST

ARRL, The National Association for Amateur Radio

The question now is, where do I find the ground for the house? I know there is supposed to be a main ground rod that the panel ties into, but how the hell do I find it?

Thanks!
 
Yep...the power supply is a 12VDC supply for the radio equipment.

The comments about the ground is interesting. I also sent this scenario to W1ZR (The Doctor).

Here is his commentary on it.



The question now is, where do I find the ground for the house? I know there is supposed to be a main ground rod that the panel ties into, but how the hell do I find it?

Thanks!


How old is the house? Is it a rod or is the panel grounded to a pipe? Basically find the panel and trace the ground back to source, which is harder than it sounds.
 
Lights throughout the house flicker slightly while transmitting.
This is the one I can't figure out. The rig can't be drawing more than 400W from the wall. Maybe I could understand that dimming the lights on one circuit, but not through the whole house. At most you're only pulling an extra 3 or 4 Amps through a 100A panel when you key down.

If you plug a hair dryer into the same outlet and let it pull 1,000W, do the lights also flicker?
 
How old is the panel? If you pull the cover off, do you see any corrosion inside on the bottom or on bus bars?

What type of panel is it? We had a place that was built with counterfeit Square D breakers. The breakers were sketchy and you'd get things like flickering lights when turning other circuits on. The breaker tabs for mounting were shit metal and when I removed them the was corrosion present between the clip and bus bar. Replaced all the breakers and it went away.

https://www.lanl.gov/safety/electrical/docs/counterfeit_squared_circuit_breakers.pdf

https://thecounterfeitreport.com/product/101/Electrical-Circuit-Breakers.html

I think the lights flickering is unrelated to the other issue.
 
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Ok, the house is about 20 years old. The panel looks fine from what I can see.

I agree with cockpitjob on the flickering light thing. The last time I did the test was around 11pm when the kid was in bed and the wife was upstairs in the master bathroom. She yelled that the lights were flickering on the second floor while my rig is in the basement. No major appliances (dryer, stove, etc) were running. Hell, the ACs were both off.

I'll have to check the panel to see how it is grounded. Wasn't aware that they could tie into the pipes for an earth ground. I would not be surprised if that weren't the case given the panel is in the same area where the water main comes into the house. Should make it easy to see if there is a line going from the panel to a pipe.

Will keep you all posted.
 
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Are the lights that flicker on dimmers? What kind of lights, incans, CFL, LED? The dimmer or CFL electronic ballast, or LED supply may be susceptible to either transmitted or conducted RF.
 
Are the lights that flicker on dimmers? What kind of lights, incans, CFL, LED? The dimmer or CFL electronic ballast, or LED supply may be susceptible to either transmitted or conducted RF.


Yeah, I was thinking this too. Sketchmo dimmers or other light controller could be getting hit with RF and causing flicker.

Even back in the 80s and 90s this was common with those stupid touch lamps that everyone had. You key up a CB radio and a touch lamp would flicker back and forth between settings, etc... LOL.

-Mike
 
I would almost bet that your electrical box is grounded to the water pipe and not a ground rod. You most likely need to ground your electrical system with a ground rod and make sure you bond your grounds for the radio. The ground rod that your gear in connected to needs to be the same ground as your electrical panel. "A difference in potential between two grounds can cause weird issues". I don't think you are having an RF issue, you would be experiencing other anomalies, like smoke detectors going off or interference on your computer speakers and maybe even shocking yourself on your microphone.
 
Yeah, I was thinking this too. Sketchmo dimmers or other light controller could be getting hit with RF and causing flicker.

Even back in the 80s and 90s this was common with those stupid touch lamps that everyone had. You key up a CB radio and a touch lamp would flicker back and forth between settings, etc... LOL.

-Mike

Completely forgot about touch lamps. Lol. What a terrible idea that was.
 
Are the lights that flicker on dimmers? What kind of lights, incans, CFL, LED? The dimmer or CFL electronic ballast, or LED supply may be susceptible to either transmitted or conducted RF.

Well, I have a mix of incandescent, CF and LED through the house. Pretty sure the bathroom globes are incandescent....but will check. I definitely notice it on the CF I have in my lamp on the bench. I do have dimmers in the basement and notice the flicker on the incandescent bulbs there...so you may be onto something.

Here is the reply the ARRL lab guy just sent.

I'd say that Joel's answer about covers it. The only other thing that I might add is if you can narrow it down to a particular circuit by tripping breakers, look for a length of cable that is about 1/4 wavelength at the frequency causing the problem. You may be able to break it up by adding a toroid core (common mode choke) to the cable, but this is probably not practical. The cable is most likely in the walls of your house, etc.

One other thing that might help is to look for cases in which the house wiring goes to the load, and then wiring to a switch is also connected at the load. It might be better to run the cable from the service entrance panel to the switch, then from the switch to the load. However, this may not be practical or easily done.

73,

Mike Gruber, W1MG
ARRL EMC Engineer

Not sure that any of his suggestions are really practical nor do I completely understand what he is suggesting.

Thanks and hopefully more to come.
 
Ok, is THIS my ground? I'm thinking the black cable is the ground for my panel as it goes into the panel. The grey wire seems to go out of the house. I'm thinking I can just run a wire from the grounding rod outside the house (the one I buried) to that same point and I should be gold, right?

NGEEJ23.jpg
 
Aye, the black wire to the panel is your ground. The grey wire looks like a telco ground wire so it makes sense that it is going outside.

I am not an electrician but ideally a home would have a driven rod as a ground and a bond to the cold water supply line. Bonding your existing equipment ground rod to that connection would eliminate any chance of a difference in potential. The new bonding cable should be the same gauge as your existing ground cable so it probably won't fit in that connector clamp. You could run the new bond wire into the service panel or bond the new cable to the cable in the pic by removing some of the jacket and use a connector similar to this.

22A994_AW01
 
First thing I would do is try and rule out power distribution issues (think thats the direction the ARRL guy is hinting at).

If you have old style filament bulbs flickering when you transmit you PROBABLY have a power distribution issue. Any new style fixtures with LED's, electronic ballasts, light dimmers, GFI outlets, and even CFL bulbs can all be affected by RF and cant be used to rule out PD issues. If you can find a flickering incandescent bulb with no dimmer or GFI outlet I would bet there is a distribution issue.

Your house has 220V with a neutral coming in to the breaker panel (2 black wires and a bare wire). The bare wire should be heading to a ground stake AND to the neutral bar in the main breaker panel. One of the black wires (L1) powers half the 120V circuits in your house, and the other black (L2) wire powers the other half. So L1 to Neutral is 120 volts for half the house and L2 to Neutral is the other half.

I would start by figuring out if your rig is connected to L1 or L2. You might physically be able to look at the breaker box and figure it out. You can also use an amp clamp. Turn off all breakers in the place and plug a decent wattage device (electric heater maybe) into the same outlet as your rig (turn it on). In the breaker panel measure amps on each black wire when you flip the breaker for your rigs outlet....note L1 or L2...pick a black wire and mark it...does not matter which one is L1 and L2.

Using the same technique I would locate a nearby outlet close to your rig connected to the other half of your panel. If your rig is on L1 you want to find a nearby outlet on L2. Turn on all the breakers and using an extension cord connect your rig to the L2 (other half of the panel) outlet and see if the problem with flickering lights continues....if it goes away there COULD be some issue in the circuit your rig is on. Often times romex goes thru several receptacles and a bad connection in any one of them might cause issues. Look for loose connections on breakers, receptacles that get warm when a space heater is plugged into them etc.
 
You are concentrating on the low impedance AC lines and that is good to eliminate. But I think we should look at the relatively higher impedance lines like the thermostat lines. These are 24 volt lines that draw low currents likely less than an amp at 24 VAC so the RF can push them around easier than a 100 amp 220 volt line with lots of low resistance loads. Maybe a choke on the thermostat wires where they enter the system? I would experiment with a ferrite or two.
 
You are concentrating on the low impedance AC lines and that is good to eliminate. But I think we should look at the relatively higher impedance lines like the thermostat lines. These are 24 volt lines that draw low currents likely less than an amp at 24 VAC so the RF can push them around easier than a 100 amp 220 volt line with lots of low resistance loads. Maybe a choke on the thermostat wires where they enter the system? I would experiment with a ferrite or two.

Yeah...I found the thermostat lines going into the air handler and there is enough slack for a couple turns on a type 31 ferite. Will order some of those and try it out.

Funny thing is, I installed my new Kenwood TM-D710G last night. Just plugged it in and started talking. Put it into cross band repeater mode and was walking around the house talking and my smoke alarms started chirping again...so I went back down to the shack and attached a ground wire from one of the screws holding the fan in place to my ground bus and that nipped the issue in the bud. Fun time!
 
The March issue of QST talks to the importance of a choke or balun at the antenna feedpoint, this helps to keep RF from coming back down the outside of the LMR400. Do you have a choke there? The grounding helps to deal with the RF in the shack while the antenna balun or choke helps to keep it out in the first place.
 
Consider;
Replace the OCF with a center fed open wire line (OWL) zepp-type antenna open wire fed directly into the shack/LDG through -ultimately- a 1:1 transformer. Unless the LDG has a balun of sorts built in.
If you can cut it ~87' a side/174' flat (5/8 wavelength on 40m) and bend the ends to fit for about the last 25 ft of the ends 90 degrees towards the ground (would need to be up at least 40 feet tho- the higher the better) -
The LDG could likely bring this into 160m too.....

Depending on the lights (LEDs? CFLs?) They may be just absorbing RF from your unbalanced antenna.
Agree with the solution from ZR about thermostat-

Keep us updated!

gl.

uj



 
The March issue of QST talks to the importance of a choke or balun at the antenna feedpoint, this helps to keep RF from coming back down the outside of the LMR400. Do you have a choke there? The grounding helps to deal with the RF in the shack while the antenna balun or choke helps to keep it out in the first place.

^^^This.


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^^^This.


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Well, I assumed the 4:1 current balun would prevent any RF coming down the coax. It thought it was meant to balance the antenna so it didn't impact the feedline.

Thanks
 
Well, I assumed the 4:1 current balun would prevent any RF coming down the coax. It thought it was meant to balance the antenna so it didn't impact the feedline.

Thanks

You would be correct if only used at resonant frequency. However, an OCFD will have widely varying currents at the feed point at different frequencies. The feed line will try and act like part of the antenna at different frequencies. An RF choke at feed point can be anything from a number of open turns of the coax to 10 or more clamp/on ferrites. The ferrite would be my choice installed on coax right at feed point.


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You would be correct if only used at resonant frequency. However, an OCFD will have widely varying currents at the feed point at different frequencies. The feed line will try and act like part of the antenna at different frequencies. An RF choke at feed point can be anything from a number of open turns of the coax to 10 or more clamp/on ferrites. The ferrite would be my choice installed on coax right at feed point.


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OOOOOHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!

Thank you for that info. I didn't know that this was the case. I have a 1:1 balun I had purchased for something else. I'll install it and see how much that helps on the non-resonant frequencies.

This is what I love about the hobby. You learn stuff everyday!
 
OOOOOHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!

Thank you for that info. I didn't know that this was the case. I have a 1:1 balun I had purchased for something else. I'll install it and see how much that helps on the non-resonant frequencies.

This is what I love about the hobby. You learn stuff everyday!

Nice. Let us know how it works. I have a 1:1 MFJ RF choke at feed point and haven't had any more shack RF issues. It's just ferrite clamps on a 1' piece of coax sealed in some pvc.


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