Hams Map Powerlines for Low Frequency Interference

Are you within one kilometer of a PLC power line? Two new Amateur Radio bands, 2200 and 630 meters, have an FCC requirement to register ham station locations 30 days prior to use. Operators can map their proximity to high voltage lines that could have Power Line Carriers or PLCs.
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Typical map of power lines for gauging potential PLC interference

The active line frequencies and sites of Power Line Carrier system (PLC) transceivers which share the new Amateur Radio frequency range (135.7-137.8 kHz and 472-479 kHz), are kept confidential by the power companies themselves. The power line companies are not FCC-licensed for these frequencies, thus they aren't required to register their frequencies in the public FCC database. But, these unlicensed powerline radio frequencies have nonetheless been protected by bureaucratic slight-of-hand. It tends to shield their essential infrastructure control systems somewhat from the vulnerability of general public knowledge.

This also presents a huge hurdle for operators in the Amateur Radio Service of USA who now want to quickly find locations where they can operate on these new ham bands. Perhaps this whole registration process was put in place to scare them away, but, ham operators are a resourceful lot. Eventually, amateur operators will develop their own crowd-sourced database of where the lines that carry these ham-band-sharing PLCs are. But, for now, it will be a time-consuming process of trial-and-error reverse engineering of their database to find a good QTH for operating in our new ham bands.

A combination of several free online geographic mapping tools can be utilized to make the task of finding an interference-free QTH easier: OpenStreetMap with its utility program called Overpass-Turbo; and Google Earth. Here is a quick guide on how to use these to determine one's own QTH geographic coordinates and the distance to some of the known overhead high voltage lines.

This example below in Overpass-Turbo shows how to map some of the lines near a typical ham QTH in the Silicon Valley area of Santa Clara county, California.
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Example of using the Overpass-Turbo wizard to find power lines in your county

1. To start with, go to the OpenStreetMap utility site, Overpass-Turbo.eu
2. Click on the Wizard button.
3. Copy and paste the following into the Query Wizard textbox:

type:way & (power=line) in "Santa Clara county CA USA"​

4. Click on the [build and run query] button.
5. Zoom to the local map area
6. View the location of possible high voltage powerlines (it shows lines higher than 69 kiloVolt)

Now repeat the process, but this time in the Query Wizard, change "Santa Clara county CA USA" to one's own county and state instead. For example, the query for Albany county New York would be:

type:way & (power=line) in "Albany county NY USA"​

The Export button of Overpass-Turbo to download a *.KML file, which can be opened by Google Earth or imported into Google My Maps.
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Image of a *.KML file imported into Google Earth with the Edit Placemark showing QTH coordinates. The distance ruler measurement tool can be set to kilometers to find the distance from the QTH to the nearby power lines.

Once the desired QTH location is found on Google Earth, put a placemark there.
In the Google Earth - Edit Placemark box, you will see the Latitude and Longitude of the QTH.
This can be copy and pasted into a text editor. Then, this can be edited into the strange (slash-separated) Latitude and Longitude textbox entry format of the Utilities Technology Council's PLC Database Amateur Notification Process web form.
https://utc.org/plc-database-amateur-notification-process/

Example of converting the above example QTH map coordinates into the slash-separated format for the UTC's web form:
37°21'21.77"N = Latitude 37/21/21
122° 1'15.19"W = Longitude -122/1/15
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Utilities Technology Council's PLC Database Amateur Notification Process web form.

Enter the other pertinent information, and wait 30 days for any email response


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Note for advanced users: For some counties, the following example of a Overpass-Turbo wizard query string might add additional powerline information:

type:way & (power=line | power=cable | power=minor_line) in "Santa Clara county CA USA"​

 

Some calling frequencies
630 meter band calling frequencies (kHz)
472.5 CW (center frequency)
473.0 Digital (center frequency)
473.0 Upper Sideband Phone & Multimode (dial frequency)
474.0 Digital (center frequency)
475.0 Digital (center frequency)
476.0 Digital (center frequency)
476.0 Upper Sideband Phone & Multimode (dial frequency)



2200 meter band calling frequencies (kHz)
135.3 Upper Sideband Phone & Multimode (dial frequency)
136.0 CW (center frequency)
137.0 Digital (center frequency)

 

Bonnie,

This is a real service you have rendered to fellow radio amateurs. Congrats!

73
Chip W1YW

 

I kept getting an error when copy/pasting the query into the Wizard. I found if I just replaced the copied quotation marks with ones I actually typed in, the query worked. Also, I assumed the map would automatically be drawn, but I had to use the map's search box and enter my county and then I got the expected results.

It's a great tool and thanks Bonnie for sharing this tool!

73
Al WD4AH

 

Yes, it seems that the QRZ website may have mangled the quote marks in the font, or perhaps some browsers in English language operating systems may force unicode left/right quotation marks.
There are 3 types of quote marks in Unicode, but the wizard query string wants the plain old ASCII neutral (vertical) quotation marks.
Good old ASCII and Unicode U+0022 = QUOTATION MARK "
Unicode U+201C = LEFT DOUBLE QUOTATION MARK “
Unicode U+201D =RIGHT DOUBLE QUOTATION MARK ”

So you may have to re-type the quotation marks manually.
Or you can simply launder the copy/paste string through an editor such as Notepad++

 

Type the Query in the Wizard by hand....that way it does not get "Bolluxed"

Especially the Quotation Marks. .. "Type those yourself."

Thank You Al WD4AH

 

Very helpful.

It appears to be clear at this QTH.

You can 'print' to a pdf for your records.

 

So are you saying that PLC's only operate over high voltage power lines ? Or are there other transmission lines that carry PLC data that don't show up on the map that we may not know about. My QTH is 2KM from nearest HV lines. I may be ok then. I have filed with the UTC and will wait 30 days as per FCC requirement.

 

The issue is proximity to a PLC transceiver, which uses the power lines as a transmission line. In general, the distance to the power lines appears to be the guiding determinate.

 

Chip (and others), this is correct. A few items to remember:

1) Narrowband PLC systems operate exclusively on high voltage lines in modern practice. Only UTC knows what's in its database, but if it includes anything on the customer side of the transformer, I'd be surprised.

2) The permitted frequencies for PLC operation are 9-490 kHz. (481 kHz). The secondary amateur allocations total 9.1 kHz of these 481 kHz. The presence of a nearby power line only indicates the possibility of a problem; a PLC system may not be operating on the line, and if one is, it may not be operating within those allocations.

3) A PLC system is highly unlikely to preclude operation on all portions of both allocations anywhere in the country.

4) Perhaps most importantly, amateurs are NOT being singled out here. While PLC systems are unlicensed, they are considered important enough that advance coordination is required by every over the air user between 9 and 490 kHz, both federal and private sector (see 47 CFR 2.106 footnote US2).

Amateurs got a good deal here, and it's gratifying to see it come into practice. Applications like Bonnie's are helpful as we get underway, and I join others in thanking her.

73 de Brennan N4QX

 

Bonnie, thanks for the excellent informative contribution!

According to the map generated, my proposed antenna QTH is 1.03 KM from a potential PLC candidate high-tension line.

Of course, as you pointed out, that doesn't necessarily mean that line has PLC signals on it (yet). And according to Google, technically there it is still a gnat-hairs margin of separation outside the designated 1 KM limitation.

It will be interesting to see if UTC responds in any way. Are you going to volunteer to maintain the reverse-engineered database of Part 97 FCC licensed QTH's denied or other info provided by the UTC?

73 de John - WØPV

 

very cool....... btw, the copy/paste worked for me.

...DOUG
KD4MOJ

 

That site presents an interesting look at the local power grid infrastructure.

My QTH gets a lot of power line interference on the lower frequency shortwave bands,
a few years back the local utility installed a bunch of current monitoring devices in various places
along the distribution lines in the city. These are not the high tension lines shown in the map.

I hear those devices reporting back to the mothership every couple of minutes as a series of buzzes which decrease in
intensity, probably a result of the distance of the devices from my location.

Food for thought: might it be possible to convince the utilities to do some time division multiplexing
with their signals and allow a small dead-time that could be used for passing ham radio signals?
That would only be good for automatic digital modes such as JT9, and not CW and phone.
Of course, getting all of the utilities to agree on such a thing would probably be a bureaucratic nightmare
unless it was lead by the FCC.

 

Ooops. I didn't convert to the slash notation for latitude and longitude. I wonder if it will be accepted or kicked back in 29 days.. :-(

Dave
N2OA

 

Since the Utilities Technology Council web form doesn't offer any method to edit or correct errors, perhaps the easiest way is to just submit a new corrected entry.