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Receive Antennas (below 30MHz) For all topics related to receive antennas used on HF, MW, LW, etc. For transmit antennas use the Amateur Radio Antennas forum.

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Old 07-26-2014, 2:06 PM
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Default Reality Check, RFI from Major power line

I am reviving an old hobby of shortwave listening, and need some advice on power line interference. I am using a Kenwood R-1000, coax to a balun, and a choice of 2 antennas.

Antenna 'A' is a longwire end-fed, about 80 feet running north/south at about 20 feet (may elevate more depending on your response).

Antenna 'B' is essentially a Beverage antenna, a run of barb-wire running north/south for an unknown distance, but I think it is about 1,000 feet.

So far so good, right. Here's my problem. Running parallel to both these antennas and about 100 feet east, is a major power transmission line, one of the point to point types. If I recall, it's around 200KV. The antennas are literally in the shadow of this power line.

I cannot increase the distance from the power line. In fact, the barb wire antenna is also my principal property line.

I do NOT know yet if my interference is related to this power line. I am going to try an experiment next week and run the receiver on battery power and shut down my house at the meter. That will eliminate all the interference I can control.

However, in the mean time, I need to know if I have rocks in my head for even trying to get decent SQL in the shadow of a major power line. If so, then I will placate my interests by going out into the wilderness at night and throwing up an antenna into the trees, and stop my plans for more elaborate antennas, feedlines and accessories.

By the way, I also use a 2-meter handheld and the powerline gives me no issues on that. I know it's a lot higher frequency and all.

Also, though outside the scope of this particular forum, if anyone has thoughts on how this might influence amateur radio operations 20-meter, 40-meter, I'd appreciate it!

~Phil
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Old 07-26-2014, 7:57 PM
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Just as an aside, we have Amateur radio forums on this site as well. Your questions about 20/40m ops would be welcome there...

Anyway if I were in your situation (and I am drooling over that 1000 foot antenna....) I would strongly consider a loop, since they're less sensitive to E field noise than other antennas. Now you have several possibilities here, but one consideration would undoubtedly be portability.

You might wonder about my suggestion - if the loop is overwhelmed by other noise issues, you have the chance to move it. I'm specifically thinking about the Wellbrook or Pixel loops Expensive, yes, but they might be your best solution. Mounting it at ground level they will still work fine - and if you can put maximum distance between the antenna and those power lines, so much the better.

A skyloop or a delta loop might also work for 20/40m operation as well. Do some homework on this subject. You seem to have the room for it...a delta will receive other bands just fine (you may or may not find a tuner useful in these situations...)

The other thing I would try is to run antennas perpendicular to, never parallel to, those power lines. Random wires have very little directivity to them (unless you get them up high) but you would need to experiment

'Coax to a balun'- ? What kind of balun? Unun? 4:1? 9:1? Is it grounded? Did you bind your ground as recommended in the NEC codes (I'll let others comment on this aspect...)

This is one case I would also consider some good quality coax, not some el-cheapo RG58 type. A good quality braid, properly grounded, might also alleviate some of your issues It certainly won't hurt anything.

I would be somewhat careful with the R1000 - it has a pretty hot front end, and overloading it won't really damage your receiver, just your nerves :.>> A little adjustable attenuation, along with some static dissipation isn't a bad idea. I seem to recall that this receiver has 20 and 40db step attenuation, but that may be overkill at least in some cases

Just a few thoughts here...Mike.
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Old 07-26-2014, 10:04 PM
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Here are a few ideas pulled from our wiki - no doubt there are many more out there that a well-structured Google search will reveal

H5ANX Mk4 Delta Loop Design

YLRADIO - Western Canada's YL Radio Website

Loop Antenna Design

And if you want to try something indoors, just as an experiment to see if a loop would help resolve your problem...

The Carpet Loop -- antenna special on hard-core-dx.com

I used one of these when I lived in a 3 story condo a few years back, and it worked quite well. Certainly not as good as an outdoor antenna - but it worked just fine - in fact I even got a few Peruvian logs that I had never heard before on this antenna...always remember, it's not how loud the signal is, it's how clear it is of noise and interference. Mike
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Old 07-26-2014, 10:48 PM
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You might try an experiment to see just how much effect your actually having on your property. Wait until it gets dark. Take one of the lamps out of a dual, 4 foot shop light. Walk toward the high voltage power line while holding one end of the 4 foot lamp in your hand. My bet is that it will light up before you get under the power lines.

This is not a very scientific proof of much except that there may be enough energy to cause the lamp to glow from the EMF radiation coming from the high voltage line. On a damp night, you can hear the lines actually snapping from the corona off the cables.

There is no way I would ever consider consider ever living near one of those high voltage transmission lines. Some people have had the silver fillings in their teeth cause a bad taste in their mouth from the high voltage transmission lines. Others have had sleep problems caused by the lines. Some people have had nervous problems and or headaches caused by the lines.

Good luck on trying to eliminate your problems. It would be easier and cheaper to move.
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Old 07-27-2014, 1:53 AM
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20/40m ops... so noted, I will be more selective in my questions.

Loops... I had not considered loops, thank you. I tried a cheap premade indoor loop once and had poor results, but it sounds like this is worth trying.

Orientation of existing antennas... I would run perpendicular in a heartbeat, but it would then run under the powerlines, which is wrong on pretty much every level.

Balun is a 4:1 unbalanced, homemade, just one toroid, essentially. I have a better balun coming in the mail, dual transformer type.

Grounding: I have read the rather spirited discussions on NEC grounding. At the moment, it is grounded by a separate grounding rod, 6 feet away from my utility grounding rod. This is a variable in future experiments. I think I will simply abandon my existing ground rod and use the utility ground rod, as it is surely deeper than mine.

Coax is RG-6U, and the run to the balun is rather short, less than 20 feet.

I agree with the attenuation comment on the R-1000. I wish I had a 5 and 10 dB rather than 20, 40, and 60.

Power lines and health, thank you for your concern, it might explain my crazy neighbors! I have been here 15 years, no ill effects so far, but so noted.

So, I am going to check out loops, move my ground to avoid NEC violations, get my balun installed maybe next week, and go from there. I meant to post some S figures, will do so in a future post.

Thank you for your valuable responses!
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Old 07-27-2014, 3:16 AM
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Wow. 200 KV powerlines 100 ft away -- that's close, even for a relatively directional antenna like the 1000 footer (more or less directional off the end of the antenna, depending on receive frequency).

The 2 meter radio would probably not get much QRM because most 2 meter transmissions are in FM (unless you are one of those hams who does 2 meter CW & SSB -- then it would just be the higher frequency reducing it).

First, I would try a radio with a noise blanker. I don't know if the R-1000 has one. I know that some ham rigs have them (never had a ham rig, but have heard hams talk about using noise blankers), and CB radios have them (sometimes real good noise blankers).

If that didn't work, I'd try a loop antenna. Either the ones mentioned (which I haven't tried, but have read about here and on other forums), or a quad loop, which would be relatively easy to build.

A 20 meter loop might not be too difficult to build, and would work on a lot of SW broadcast frequencies for listening purposes. Direct the quad loop so that the two main lobes of reception are aimed away from the powerlines. And hope that works. :-) Maybe experiment with a smaller one and see if it reduces the power line noise, and go from there.

Either way, good luck. Sometimes I get powerline hash here at my QTH, but it's from the local power poles, and -- thankfully -- mostly it is quiet here. I wish I could say that for the neighbor's plasma TV.

Last edited by Boombox; 07-27-2014 at 3:22 AM..
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Old 07-27-2014, 10:31 AM
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See the JPEG in this thread for a simple project to add some variable attenuation to your setup - and some worthwhile static protection to boot

A great first timer project

Mike
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Old 07-27-2014, 6:58 PM
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Oh yes, I saw that a few hours after it went up. If I find the right pot, I'm going to replace my existing RF ATT switch with it, keep everything in the R-1000 chassis.

I changed a few things that decreased my interference by maybe 25%. One was to unground my balun. So, the balun is now 'grounded' via the coax to the R-1000 chassis. Significant improvement.

I also removed an extra side lead from the longline. I was using it earlier to compare with/without the balun, and it served no purpose after that.

Finally, I considered my PC, which is within a few feet of the receiver. The cover was half off, and it was missing a slot cover. I fixed that, and removed a high performance video card I really didn't need. (In a previous life, this PC supported multiple monitors).

I tried a few things that had no effect. I have a board on the wall in that room with all the networking, PoIP, wireless, etc... I killed the board, but it did not reduce the noise. I'm kind of happy about that... moving it would have been a huge undertaking.

I am hearing random clicks I can correlate with some appliances, I can live with that.

I am currently charging a backup battery and will try running the receiver off that instead of AC tonight.

But, you know, with a half-wit longwire, I was getting pretty good reception from hams in the 20 meter band during daylight. As an example, I am in Northern Minnesota, and I was getting pretty clear copy from a couple of operators in Georgia. That's a big improvement.

I am a long running member of other forums, and I know it can be annoying for someone to start a thread and post day-by-day events, so this is going to be it until I get my new balun, and only then if it makes a huge improvement. In that case, I simply have to tell someone, and you guys are it.

The intention of this thread was essentially a straw poll to see if I was going to be wasting my time going forward. I thank you for your positive and helpful advice. This will not post for a while because I am still on posting probation with the forum... but have a great night!
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Old 07-27-2014, 8:28 PM
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Yes it's going to be a rather long trial-and-error process. Kiling noise issues often is - particularly with the number of appliances that would turn out to be radiators but aren't really considered 'covered' under FCC rules. As an example, cable modems and cheap DSL routers are famous for being wideband RF generators.

One step at a time, take extensive notes so that you don't try the same experiment unintentionally and you will get there. It won't be perfectly quiet - you can't move those big power lines, and the power company would basically ignore you in this case - but I think you'll be able to drop your noise levels down to more tolerable levels.

GL...Mike
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