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Author Topic: Looking For A New QTH  (Read 337 times)
KG6WLS
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Posts: 507




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« on: December 30, 2007, 04:16:16 PM »

Hello Elmers,

I've been looking at properties the past few weeks and one question comes to mind. How close would you want to be next to a high tension / kV transmission line? These would not include the typical neighborhood utlitiy poles but, the large steel towers.

The one that I've had my eye on does have underground utlities and no HOA's That's a good thing. But, if I were to errect a simple HF vericle or dipole that would be approx. less than 100 yards away, what kind of receive noise will I be dealing with? The kV lines run East to West. A dipole could be strung from North to South.

Any feedback would be great.

Thanks & Happy New Year!!

73 de KG6WLS
Mike
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AA4PB
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Posts: 13032




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« Reply #1 on: December 30, 2007, 04:21:14 PM »

Before making such a big investment I'd take a receiver out there and give it a try. I often travel under a couple of these with my HF mobile and don't notice any noise. The big towers seem to be quiter than the local neighborhood lines - probably because they are better maintained.
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AC5UP
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Posts: 3956




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« Reply #2 on: December 30, 2007, 05:01:44 PM »

I've been at the same QTH for 26 years and have a big-boy transmission line approximately 1/4 mile to my south. Hasn't caused a bit of problem for me and in some ways it's a good neighbor. On a foggy day there can be some RFI coming off the insulators, especially in the fall after a few weeks of dry & dusty weather. At night if I look very closely there can be a faint burple corona dancing around some of the insulators. Best guess is the dust on the insulators becomes damp enough to create a Hi-Z path to the tower. If the fog turns to a moderate rain the insulators wash off and the RFI goes away.

This happens rarely, maybe once or twice a year. Average background noise is in the S-2 range and the insulator corona thing can push it up to maybe an S-4. Otherwise the lines are quiet and the 'good neighbor' part plays in the spring... If Thor is going to drop his hammer in the 'hood it will likely be on the towers and not on me. I have had no direct lightning hits - but - have had two near hits that hosed everything connected to the phone line and one that punched holes in the RG-6 coming down from the TV antenna. Didn't crater the TV but did zero a piece of Romex running near the outside wall in the attic and ate a clothes dryer. Been meaning to fix that... The new gas clothes dryer is still running on an extension cord.

I'm on the top of a gentle ridge and have very clean horizons in all directions, especially to the west. Works FB as a VHF location and ain't no slouch on HF. The near lightning hits were not attracted by the power lines but by a neighbor's tree. Big old dude.

If you have an HF antenna on the car I'd advise you do the same as I did: Stop by the property during the day with an SWL RX on the passenger's seat and take a spin from AM broadcast through 10 to see what you hear. If you can do this on a wet and dry day that would be a plus. Listen low during the day and if you can stop by at night listen high. The goal is to get an idea of what the residual noise level is without a band opening so that what you hear is what's in the 'hood. Be sure to tune slow around 27 MHz just in case there's a truck stop down the road.

BTW: I've had more problems with idiot dog owners installing electric fences than the high tension lines. Had a nearby freebander a few years back but that didn't last too long. It's also very cool for me that the lines are to the south as I enjoy AM BCB DX'ing and no comprende Espanol. So... The RX wires have all been attempts at a cardioid pattern to the north and I'm getting kinda' good at working the direction thing... Would have with or without the towers. Wink
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OBSERVER11
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Posts: 657




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« Reply #3 on: December 30, 2007, 05:20:43 PM »

GOOD LUCK!

I have all but given up hope on finding lot to build. Imagine the response when you say...

I'm a ham and want s 55 foot tower...
I own a 40 foot motor home and want to park it on my property.

and the topper is...
I want to build a LOG HOME.

After they stop the stare that has you thinking you must have a third eye, they usually say "uhhhh, not here".
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W7ETA
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Posts: 2527




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« Reply #4 on: December 30, 2007, 06:45:38 PM »

CB, battery operated SWL, and auto AM radios are a good way to sample RF near power lines.

But, ultimately, why take a chance?

Bob
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N0MLR
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Posts: 74




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« Reply #5 on: December 30, 2007, 07:08:37 PM »

I live on a ridge here with a high tension power line less than a quater mile away in one direction. I have had no problems that I am aware of here.
About a mile away in the other direction a power sub station with tall towers and lines going in several directions from it is in full operation. No problems from it either.
But just to be on the safe side I would do as others have suggested and run a few checks.  
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K6AER
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Posts: 3535




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« Reply #6 on: December 30, 2007, 07:40:16 PM »

It depends on the age of the equipment (Insulators), height, power and if the lines are AC or DC.

Having said that, I would not locate within 5 miles of very high tension power lines. It is just a matter of time before there is leakage.

I can pick up bad line by pointing my antenna at them and they are 6 miles away. Then I drive the road with the mobile listening on 2 meter SSB, find and mark the bad pole and then call the power company. Two weeks later or less the problem disappears.

With power lines over 50KW it is a different story. To repair those lines it cost thousand of dollars and the power company is not to quick to spend the money. I live in the country and cannot imagine what the hams do in suburbia.
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K7PEH
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Posts: 1124




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« Reply #7 on: December 30, 2007, 09:32:31 PM »

I have 345 KV lines that run north-south just to the west of me.  I am not sure how far but I think I can tee up a golf ball and reach the lines from the front of my house (let' say 200 to 240 yards).

I have never heard anything from these lines.  Indeed, in my mobile rig in my truck, I routinely drive parallel to them, almost directly underneath as they parallel the road that I drive on, and there is no interference.  And yes, the lines are active as they do bother the AM radio in my pickup truck.

My home rig is an Icom 756 Pro III using a 120 foot dipole and also a Traffie Hexbeam antenna.  My mobile rig is an Icom 706 MkIIG with a Hi-Q screwdriver antenna.

However, I wouldn't want to be any closer.  By the way, about 1/4 mile east of me is another circuit but it is much lower voltage, I think it is 65 KV.  The 345 KV lines are a major transmission line system bringing power into Seattle City Light from their hydro plants up around the north Cascades.  The smaller voltage circuit to the east of me is owned by Puget Power and they are a substation feeder circuit.
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KG6WLS
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Posts: 507




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« Reply #8 on: December 30, 2007, 10:25:34 PM »

Thanks for the replies. This is just one of a few properties that I'm looking at. I think that the one I mentioned may be a little bit closer than I'd care for but, I just wanted to get some input. If I used a sand wedge, I could probaly hit the first tower without much effort. HI.

Thanks again.

73 de KG6WLS
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ONAIR
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Posts: 1747




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« Reply #9 on: December 31, 2007, 12:55:47 AM »

   Best bet is to find a piece of land and build your own home on it.  No HOAs, and you can be on top of a mountain if you like!
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K9KJM
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Posts: 2415




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« Reply #10 on: December 31, 2007, 03:29:20 AM »

I agree that most all HV lines around here are very well maintained and not any problem.

I also agree that building your own new house is the way to go. Act as your own general contractor to save big money, If you can do any of the finish work you will also save big money.
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W8ATA
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Posts: 327




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« Reply #11 on: December 31, 2007, 06:49:12 AM »

I agree that taking a receiver into an area to sniff out noise is a prudent thing to do. It's not just power lines that are a concern. Some manufacturing plants are a real problem even up to a mile away in my case. I have an MFJ-852 line noise meter which is essentially an AM receiver on about 135MHz which has a directional antenna. It's amazing what I hear in my general neighborhood. A small AM transistor radio with a telescoping antenna and held horizontally will accomplish about the same thing. I have a friend who has made several moves and never decides on a QTH location without first taking some HF rig along that receive only power is some how available for and using a small vertical to see what noise level exists on HF. We can mow the grass, keep the weeds down, and rake the leaves, and keep the neighbors happy, but we can't always fix the inherent noise.

Best to you,

Russ
W8ATA
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WB2WIK
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Posts: 20666




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« Reply #12 on: December 31, 2007, 12:51:48 PM »

Yeah, I'd do the "sniff" test also, at the very least with the AM BC radio in my car.  Tune between stations or below 540 or above 1600 kHz where there aren't any stations and drive around the block a few times, see what kind of noise level the car AM radio has, then drive farther away from the HV towers and see if it changes.

If the noise level is low and there's no change when you drive farther away, good chance the towers aren't doing much harm to the HF spectrum.  However, of course anything can change with time, or even with the weather.  

Here in L.A., our local utility is City owned (LADWP) and very, very well maintained.   They're also extremely responsive to customer calls: I don't have any power line noise, but saw what appeared to be a ground wire hanging loose from near the top of a utility pole about a block from me, and called them to report it.  It was less than two hours until the repair crew showed up with two bucket trucks and four guys, and that loose wire (never did actually find out what it was!) was replaced and the crews were pulling away.

If your local utility provides that level of service, you may be in good shape.  The way to find out, of course, is to ask neighbors.  Lots of neighbors.  Lots of questions.  I'm never shy about ringing a doorbell to ask a prospective neighbor a question or two about the neighborhood.

"Hi, I'm thinking about buying next door to you and don't know this neighborhood very well.  Could you tell me a few things about it?"

Almost everybody is PLEASED to show off how much they know.

You might also do a zip code search on the FCC ULS data base for other hams in the zip code you're thinking of buying into: Then compare the results to your propsective new address and see if you can find hams that live closeby, preferably within a mile.  Contact all of them, and ask them about the area.

I do that -- without fail.

WB2WIK/6
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