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Dipole noise level

longhaireddwb

longhaireddwb

W9WDX Amateur Radio Club Member
Oct 8, 2008
555
30
38
Colorado Springs, CO
I put up a dipole for my Kenwood TS850S so I can talk to the moon.
Anyway, I have so much noise on 80M and on 40M its ridiculous! 10 to 20 over 9! I have my dipole tuned for 40M, SWR set at 1.4:1 to 1.6:1 and have made an "Ugly Balun" (21ft coiled at 5" loops and not overlapping coils) and put it right at the connection of the feed line (coax) of the dipole. and its about forty feet in the air almost horizontal to the ground.

I was wondering if I was to take the ground end on the dipole bring it down at an angle and connect it to an 8ft. ground rod buried in the ground would that help the noise level? Or would this just throw the balanced line off being to long on the ground side?:redface:

All comments and opinions will be appreciated!
 

I was thinking that with this thing being so high in the air I'd have to lower it to put the ground end onto a ground rod as the ground radial is not long enough to go to ground without being straight down.

Any comments on this?
 
Is the dipole running near power lines? Especially parallel to them? If you can reconfigure it about 90 degrees from its current orientation, you might null out some noise.

I would NOT attach either end to ANYTHING, much less a ground rod. First thing to do is find out where the noise is coming from, following the usual procedures.

I'm assuming since the dipole is adjusted for 40 meters that you're only listening on 80, right?

40 feet isn't a bad height for a 40 meter dipole (it's higher than 80% or more of us can reasonably get). Something, somewhere, is generating noise, and the first thing you should do, as I said, is find out where and what it is.
 
I forgot to mention I'm running this into a MFJ 949D tuner and I'm able to tune from 1.0:1 to 1.2:1 on 10m, 12m, 15m, 17m, 20m, 40m and 80m.

The noise level changes throughout the day. sometime high and other times it will drop to 5 s-units. The power supply line to the house is about 10 feet below this antenna and comes from the same corner of the back yard. Although the antenna is about 10 - 15 degrees off the supply line at the ground end. Not exactly parallel. What about switching the two ends of the antenna? doing a 180 with it?

I've never read up on the theory antennas just went for broke.
So you think the location the antenna to power supply line to the house could be causing the noise? What if I turned the power off to the house and see if there's a difference?? Would that be a plausible test? The wife would kill me for screwing up all the clocks and things but what the hell. I was hoping with it being high enough above it wouldn't cause a problem but what do I know. :oops:
Anyone else have an other or more ideas?
 
Yes, killing the power to the house is a good way to eliminate your own house being the source of the noise. As long as your radio can run from battery for that test.

Another way is to walk around with a portable AM broadcast receiver when the noise is at it worst. Find a station which is interfered with same noise, and walk around the neighborhood.

If the noise source cannot be eliminated, you might consider the ANC-4 timewave noise chancellor.
 
longhaireddwb said:
I forgot to mention I'm running this into a MFJ 949D tuner and I'm able to tune from 1.0:1 to 1.2:1 on 10m, 12m, 15m, 17m, 20m, 40m and 80m.

You may see the meter on the tuner drop down to a nice level, but that level is just what the radio sees. On 80M, with an antenna cut for 40M, you're probably losing well over half of your power. The SWR on the feedline is not changed by a "tuner". The actual SWR on the feedline is likely well over 20:1. Open/parallel wire feeders would be a lot better as far as losses, but coax is a terrible choice for this kind of antenna.
The noise level changes throughout the day. sometime high and other times it will drop to 5 s-units. The power supply line to the house is about 10 feet below this antenna and comes from the same corner of the back yard. Although the antenna is about 10 - 15 degrees off the supply line at the ground end. Not exactly parallel. What about switching the two ends of the antenna? doing a 180 with it?

Doesn't matter which end is which - or it shouldn't. Try it; it won't cost anything. But that close to the power line is a pretty bad choice for a location.

I've never read up on the theory antennas just went for broke.

That's obvious (and no offense is intended). A few years of practical experience will help a lot, but you need to be familiar with some of the basics. I'm still learning myself, and I've been licensed and working in the hobby and the profession for a bit over 50 years. Get some basic texts, like the ARRL or RSGB Antenna Books.

Antenna work is the one area of radio where experimenting is legal for everybody (as long as public safety is observed). It's also an area where improvement or degradation of one's signal is immediately apparent. Have fun, but know the basics of what you're doing.

 So you think the location the antenna to power supply line to the house could be causing the noise?

Yes.


 What if I turned the power off to the house and see if there's a difference?? Would that be a plausible test?

That's one of the "usual procedures" I alluded to earlier.

The wife would kill me for screwing up all the clocks and things but what the hell. I was hoping with it being high enough above it wouldn't cause a problem but what do I know. :oops:

Ten feet isn't anywhere NEARLY enough separation!


 Anyone else have an other or more ideas?
Click to expand...

Good luck!
 
Thanks for the reply Beetle. I don't have a lot of options on the location of the dipole. I'm thinking I need to see about some more funds and put up a vertical HF antenna. I can put it on the side of the house away from the power supply for the house. I'm just not too sure how the wife is going to like it. Plus for an all-bander its a lot of money.

I'll do some testing and see if the supply to the house is causing the noise. Thats the only power wires around so I don't know what else it could be.

When I put up the balun I seen a difference of 1db in noise. Not an s-unit just about 1db according to my radio meter. It didn't help much in the SWR settings of the bands. I'm thinking its not really helping much.

If I was to reconfigure this antenna into a up-side-down V maybe it would help? Like you said, it don't cost anything to try.

I'll see what the locals have to think about this and get some help.
 
The difference with and without the "balun" could easily be attributed to the length of the coax you wound into the choke (it's not really a "balun".) Longer coax = greater ohmic loss. And I wouldn't try reading any S-Meter down to the "1 dB" increments. They are for relative indications only, for the most part.

There are LOTS of things that can cause broadband noise. Do you or any close neighbors have a plasma TV? Heated aquarium? Thermostats?

If the noise source is somewhere in YOUR house (run the radio from a battery and turn off the main breaker to the house. If the noise goes away, turn the main breaker back on (which should cause the noise to return, UNLESS it was something that has to be reset). When the noise does return, start turning off individual circuit breakers, one at a time, keeping an ear on the received noise level.

If it's NOT somewhere in your own house, then it's time to start discreetly wandering around with a portable AM radio tuned between stations just to hear the noise. Look for where the noise becomes louder...you get the idea.

The idea of making it an inverted vee might work a bit better, although it's probably still going to be close to the power line. I would get rid of the coax, though, and use tuned feeders (ladder line/window line).
 
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it might be the power supply...I have one that I can not use for 40m-160m if you have a battery that you can use for the test give it a try...
just a thought
 
That dipole should be quiet, if you live inside a city, which it seems like you do with the lot size, there are all kind of different sources of noise.

Try disconnecting the dipole and see what noise you get with just the rig on?

Try different times of the day, also kep in mind it is Winter time and furnaces.heaters and famous for making noise all across the HF band, especially those electric space heaters.

Good luck on finding the source
 
On 40 80 and 160 meters I have seen many times a noise level at 8 to 9 on my meter that was not caused by the power lines,just plain old atmospheric noise.For me personally 3 to 5 on my meter is pretty common pn those bands.It is 7:30 AM centeral time as I am posting this and I am showing 5 to 6 on my meter at 3.900 mhz

I will admit that my antenna is fairly close to power lines...But I am really surprised at how little interference I am getting from the power lines...they are about 150 feet from antenna at the most.But as usual stay as far away as possable from power lines,if nothing else for safty.

I am running a Buxcomm OCF windom at about 38 feet and it is running pretty well paralell to the lines...It is well worth the time to search out the cause of the noise...at least you will know if it is man made or not
 
Noise is.
I think it's very safe to say that noise at some level is always going to be present. It's also very safe to say that the lower you go in frequency, the more noise will be present. That noise has a lot of sources, most of them man made in some form or fashion, and don't forget 'Momma Nature', she makes some noise too.
Noise varies according to where you happen to be listening to it, the frequency and where you happen to be. On 80 and 40 meters, where I am, it's very unusual to have noise levels under maybe an 'S-5'. Something between 'S-5 and 'S-9' is more 'typical'. That's not 'peaks', but an average sort of noise levels. I tend to think something is 'wrong' if it isn't at those sort of levels. Everything electrical makes noise of some sort at some level. If you live in town, or sort of close to other people, expect there to be noise. If you live near large users of electricity, there will be more noise.
Having said that, noise levels over an 'S-9', -here-, are not all that common, it means that something is happening that's unusual. That's probably about as normal as it gets anywhere, not just -here-. If I experience loud noises, I start looking for it close to me, in house. Then further away. Very loud noises don't necessarily mean that the source is 'in house', but it's a fairly safe bet, you know? If that noise is everywhere, all bands, then it's an even better bet that the source is close, at the very least.
Is any of that all that pertinent to your noise problem? Not really, but it may help narrowing things down some. The biggy is to find 'changes', what's changed recently that might contribute to the problem.
Once upon a time, the power company replaced the distribution lines behind the house. I figured things were going to be SOOO much better! Wrong. It was SOOO much worse until things sort of 'wore in', got rained on a few times. It took awhile, but it is better now.
- 'Doc
 
Did some testing and got some help from the local hams and this is what we came up with. If I want to put up a tower higher than the power lines that are all around me with a beam then I might beet the noise. I hadn't realized that the house across the street has power lines behind it along with a transformer. The house behind me has power lines in front of it and the house across the street to my right has power lines behind it. I live on a corner lot and have lines on 3 side of me. I switched the dipole to be at a right angle to the supply line to the house. Turned off everything in the house with the main breaker and hooked the radio up to a battery and still got 10 - 20 pounds over 9 of noise!

I'm screwed!:(

I'm renting this house so spending 1500 to 2000 on a killer beam and tower is not an option. Besides the cost of such a thing the owners will not go for it! There not real happy about my 2m and 11m antennas already and they don't know about the dipole.

Well I'll have to live with this. Thank you all for giving me the ideas and things to check out. I guess I'll spend more time on 20 and above.
 
There may be some options for recieve antennas that will allow you to work the lower bands with your dipole, but use a seperate receive antenna,

Google is a friend on this one, all sort of recieve antennas out there that may or may not help in your noise situation.
 
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Do you think this will help?

Ham Radio Outlet | TIMEWAVE ANC-4 | RF NOISE CANCELLER

I just got mine and tested it at my parent's house. There would be a S7 buzz whenever the bathroom light was turned on. When properly tuned, the buzzing was almost gone and I was able to hear signals which the buzzing had covered. I'm taking this baby back to my apt tomorrow to test it there.

longhaireddwb said:
Did some testing and got some help from the local hams and this is what we came up with. If I want to put up a tower higher than the power lines that are all around me with a beam then I might beet the noise. I hadn't realized that the house across the street has power lines behind it along with a transformer. The house behind me has power lines in front of it and the house across the street to my right has power lines behind it. I live on a corner lot and have lines on 3 side of me. I switched the dipole to be at a right angle to the supply line to the house. Turned off everything in the house with the main breaker and hooked the radio up to a battery and still got 10 - 20 pounds over 9 of noise!

I'm screwed!:(

I'm renting this house so spending 1500 to 2000 on a killer beam and tower is not an option. Besides the cost of such a thing the owners will not go for it! There not real happy about my 2m and 11m antennas already and they don't know about the dipole.

Well I'll have to live with this. Thank you all for giving me the ideas and things to check out. I guess I'll spend more time on 20 and above.
Click to expand...
 

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