Hams Map Powerlines for Low Frequency Interference

Discussion in 'Amateur Radio News' started by KQ6XA, Sep 18, 2017.

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  1. KQ6XA

    KQ6XA Ham Member QRZ Page

    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.
    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.
    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.
    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.

    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
    Utilities Technology Council's PLC Database Amateur Notification Process web form.

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


    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"

    Attached Files:

    Last edited: Sep 18, 2017
    KM6MHZ, SWL37632, KB5WCK and 7 others like this.
  2. KQ6XA

    KQ6XA Ham Member QRZ Page

    Some calling frequencies[​IMG]
    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)
    Last edited: Sep 19, 2017
    KM6MHZ, SWL37632, KO6KL and 5 others like this.
  3. W1YW

    W1YW Ham Member QRZ Page


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

    Chip W1YW
    SWL37632, KO6KL, W7UUU and 1 other person like this.
  4. WD4AH

    WD4AH Ham Member QRZ Page

    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!

    Al WD4AH
    KM6MHZ, KO6KL, KF1P and 1 other person like this.
  5. KQ6XA

    KQ6XA Ham Member QRZ Page

    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 "

    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++
    Last edited: Sep 19, 2017
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  6. KF1P

    KF1P XML Subscriber QRZ Page

    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
    WD4AH and KQ6XA like this.
  7. W1YW

    W1YW Ham Member QRZ Page

    Very helpful.

    It appears to be clear at this QTH.

    You can 'print' to a pdf for your records.
    KQ6XA likes this.
  8. N3HEE

    N3HEE Ham Member QRZ Page

    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.
    KQ6XA likes this.
  9. W1YW

    W1YW Ham Member QRZ Page

    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.
  10. N4QX

    N4QX Platinum Subscriber Platinum Subscriber QRZ Page

    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
    N0TZU, KQ6XA and W1YW like this.

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