Question: Lightning Protection

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Ewan Parsons

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Jan 24, 2021, 9:17:36 AM1/24/21
to Motus Wildlife Tracking System
I am interested to hear about experiences with lightning strikes and protection of Motus receivers.

As we expand the UK network or receiver stations the owner of one potential receiver site has concerns about the risks of lightning striking the antenna and affecting the equipment inside their building.

We have had not strikes on the small number of UK receivers so I'd like to get some data from the wider community on the following:
  1. How many of your receiver stations been struck by lightning, and have any had multiple strikes?
  2. If a station has been struck by lightning:
    1. What type of structure was it on e.g. building, tall mast, low mast, lighthouse etc.
    2. What was the consequences for the receiver station?
    3. What was the consequences for the building/ structure?
  3. What steps have people taken to avoid their systems being struck by lightning, e.g. installation of lightning conductors around the antenna.
  4. Does anyone use protection devices on the coax to protect the receivers, e.g. lightning/ surge protectors, earth bonding clamps etc.?
Many thanks.
EAP

Ewan A. Parsons
UK Bird and Bat projects.

Stuart Mackenzie

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Jan 24, 2021, 9:25:28 AM1/24/21
to Ewan Parsons, motu...@googlegroups.com

Hi Ewan

 

You can view some previous discussion on this matter if you search for ‘grounding’ in the group - https://groups.google.com/g/motus-wts/search?q=grounding. ‘Lightning’ mostly returns conference correspondence.

While I’m certain that some stations have experienced lightning strikes, they are exceedingly rare, and I have not personally encountered any. In terms of defense we recommended grounding, lightning rods, and/or surge protectors, where it make sense to do so. In almost all cases it’s to protect other electronics and infrastructure, not the Motus station itself.

 

Others have gone to more extravagant measures at some locations and I’m sure you’ll hear from them.

 

We are extremely interested in any feedback you receive so that we can include recommendations in expanded resources for the network.

 

Regards,

 

Stu

 

 

Stuart A. Mackenzie

Director, Migration Ecology

Birds Canada | Oiseaux Canada

PO Box 160, 115 Front Rd. Port Rowan, Ontario. N0E 1M0.

Office: (519)-586-3531 X 162 | Mobile:820-6040

smack...@birdscanada.org| birdscanada.org |motus.org|birdscanada.org/lpbo

 

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The Motus Wildlife Tracking System (Motus) is an international collaborative research network that uses coordinated automated radio telemetry to facilitate research and education on the ecology and conservation of migratory animals. Motus is a program of Birds Canada in partnership with collaborating researchers and organizations. Learn more at https://motus.org
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Paul Foster

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Jan 24, 2021, 10:34:39 AM1/24/21
to Ewan Parsons, Motus Wildlife Tracking System
Hi Ewan,

I’m very interested in this topic as well. I learned at one of the Motus discussions that putting a lightning protector (polyphaser.com) on both ends of each coaxial cable has been used. 

-Paul

Paul Foster
Pronouns: he/him/his


Director,
Bijagual Ecological Reserve
Apdo. 35-3069
Puerto Viejo de Sarapiquí
41001 Costa Rica

Associate Adjunct Research Scientist
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Jim Moore

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Jan 25, 2021, 10:11:43 AM1/25/21
to Paul Foster, Ewan Parsons, Motus Wildlife Tracking System
I have had my share of lightning strikes with my Ham radio activities and also LAN networking.  One caveat is to compare the cost of surge protectors compared to the cost of the hardware it is supposed to protect!  This is particularly true with LAN routers and switches.

Cheers

-jim (aka W3ASA)

Patrick D. Lorch

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Jan 25, 2021, 2:44:53 PM1/25/21
to Ewan Parsons, Motus Wildlife Tracking System
Hello Ewan,
    All of the four Motus towers I have helped install have been on buildings, where you worry about stray current jumping into the building from the antenna.  We followed the example of radio antenna installations that were already in place and advice from electricians.  We ground whatever the antennas are attached to (tower or pole) with a heavy wire, as directly as possible to a strong ground, in one case installing a 8 foot ground bar and grounding directly to it.  Then we also ground each antenna wire coming in with a polyphaser that is attached to a ground near where the sensorgnome sits in the building.  We have not had known lightning strikes.

Patrick Lorch

Manager of Field Research
Cleveland Metroparks
2277 West Ridgewood Dr.
Parma OH 44134
440-253-2167 (Office)
216-310-7180 (Mobile)
p...@clevelandmetroparks.com
http://clevelandmetroparks.com

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Corey Wotring

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Jan 25, 2021, 2:44:53 PM1/25/21
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Consider it an insurance policy. Best practice would be to use lightning protection such as a polyphasor on each antenna feed line and bonded to your grounding system. Only one is required per feed line. Having more than one per feed line is not necessary and contributes to extra line loss. They can be pricey and you may take into account the overall cost of the system to replace.  It could be a worthwhile investment.

Corey Wotring


To view this discussion on the web visit https://groups.google.com/d/msgid/motus-wts/D2DF4A1C-0E05-4755-A3E2-B6104DCB8373%40bijagual.org.

Erin Strasser

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Jan 25, 2021, 2:44:53 PM1/25/21
to Motus Wildlife Tracking System, Paul Foster, Ewan Parsons, Jim Moore
Hello all, 

At Bird Conservancy of the Rockies we are planning to install polyphasers for each of our antennas mounted on the station. This will end up being a significant cost when it's all said and done but we feel that it is worth the investment. We are installing stations in grasslands where in some cases they will be the tallest object around. Moreover, the Great Plains and Chihuahuan Desert experience severe thunderstorms. It would be a large time sink to repair damaged equipment in remote areas following a strike and we want to be considerate of those landowners providing a structure and electricity, as well as the wildlife and their habitat. Based on my limited understanding of lightning arrestors I think it's the responsible thing to do and will provide some reassurance as it can mitigate a structure or wildland fire and reduce the chances of nightmarish insurance or criminal investigations.

Matt Webb has been leading the charge investigating our best options. I'll let him share what he has found. 

Erin

To view this discussion on the web visit https://groups.google.com/d/msgid/motus-wts/E8875FEF-C2B6-47FF-9280-79F13CCC23AD%40MARSHLANDS.ORG.


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Erin Hennegan Strasser
Full Annual Cycle Avian Ecologist
Bird Conservancy of the Rockies
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Matt Webb

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Jan 25, 2021, 11:41:20 PM1/25/21
to Patrick D. Lorch, Ewan Parsons, Motus Wildlife Tracking System
Hello all,

Thanks for bringing up this important and interesting discussion.  As Erin Strasser said above, we are using Polyphaser brand lightning arrestors (IS-50NX-CO gas tube or VHF50HN-B filter type).  These items do add considerably to the cost of each station, but work well to protect it from surges due to lightning strikes.  Gas tube type arrestors (~$80USD) degrade over time, and it's not obvious how much they've degraded or whether or not they're still functioning, whether before or after a strike.  The best way to tell is to use an antenna analyzer and check the VSWR of each antenna at regular visits. With degradation, your VSWR measurement would get worse and worse.  With a Filter type arrestor (~$115USD), however, there is no degradation overtime.  It either works or it doesn't.  You can see if it's working by measuring VSWR with the arrestor connected, then remove it and see if your VSWR improves.  If so, the arrestor needs to be replaced.  (If not, there are lots of things that could be going wrong...)  Keep in mind that a simple continuity test with a multimeter will not tell you anything about the health of any type of arrestor.

If your station were to be directly struck by lightning, chances are that your antennas would show some type of damage and need to be replaced, but if you have an arrestor in line, your station equipment would still be fine.  Most strikes that occur are near-strikes that can cause power surges to take place, in which case no equipment is damaged, and the arrestor protects your equipment again!  In both cases, you're still better off with the arrestors than not.  

And, since I mentioned it above, you'd probably be well served to have an antenna analyzer on hand!  A good, affordable option that I have found to work well is the NanoVNA (https://nanovna.com/), which costs about $60USD.  There are lots of user forums and youtube videos for how to do what you need using a NanoVNA.

Thanks, and let me know if you have any other questions!
Matt


Matthew M Webb

Avian Ecologist and Motus WTS Coordinator, Full Annual Cycle Monitoring Program

Bird Conservancy of the Rockies

Motus project #281

970.482.1707 x36 (office)

970.405.7155 (mobile - use this number!)


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To view this discussion on the web visit https://groups.google.com/d/msgid/motus-wts/AB0F8707-11C9-484F-B260-6A528B6251A1%40clevelandmetroparks.com.

Adam Smith

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Jan 26, 2021, 1:08:59 PM1/26/21
to Motus Wildlife Tracking System
Good information here. Thanks Erin and Matt!

However, I don't expect any inline coaxial lightning arrestor technology will protect against very close or direct lightning strikes. I think these devices are meant to protect the downstream electronics (SensorGnome/SensorStation) against surges from nearby (but not too nearby) strikes...

Cheers!
Adam

Patrick D. Lorch

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Jan 26, 2021, 1:59:02 PM1/26/21
to Adam Smith, Motus Wildlife Tracking System
I think Adam is correct.  I think we are also talking about best practices.  Having recently repurposed two old radio repeater towers, this is how they are set up.  I would argue that especially the new sensor stations are worth the cost of protecting them.  As I am becoming aware after a recent sensorgnome failure here, we need to remember it is not just the cost of replacing the device, but also the cost of your time to fix it.  You also lose data while you are down.

     -Pat


http://sig.cmparks.net/cmp-ms-90x122.png

Patrick D. Lorch
Manager of Field Research

2277 West Ridgewood Drive

Parma, OH  44134

440-253-2167 (Office)
216-310-7180 (Mobile)
clevelandmetroparks.com


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To: Motus Wildlife Tracking System <motu...@googlegroups.com>
Subject: [motus-wts] Question: Lightning Protection
 

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Hello Ewan,

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The Motus Wildlife Tracking System (Motus) is an international collaborative research network that uses coordinated automated radio telemetry to facilitate research and education on the ecology and conservation of migratory animals. Motus is a program of Birds Canada in partnership with collaborating researchers and organizations. Learn more at https://motus.org
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The Motus Wildlife Tracking System (Motus) is an international collaborative research network that uses coordinated automated radio telemetry to facilitate research and education on the ecology and conservation of migratory animals. Motus is a program of Birds Canada in partnership with collaborating researchers and organizations. Learn more at https://motus.org
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