# What is this small antenna on top of some telephone poles **URL:** \ **Category:** Factual Questions\ **Created:** [July 9, 2020, 2:15pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828 "2020-07-09T14:15:03Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Honolulu\_Lulu](https://avatars.discourse-cdn.com/v4/letter/h/87869e/32.png) [@Honolulu\_Lulu](https://boards.straightdope.com/u/Honolulu_Lulu)\ **Post date:** [July 9, 2020, 2:15pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/1 "2020-07-09T14:15:03Z")
I’ve seen these small antennae on top of several telephone poles in the past few months. My first thought was they they were 5G mobile antennae, but google has photos of something else for that. Each wire that extends outward from the bottom of the object is about one foot long. [http://www.bizer.com/000thingy.jpg](http://www.bizer.com/000thingy.jpg) ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [July 9, 2020, 3:33pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/2 "2020-07-09T15:33:51Z")
I see the Honolulu has a [Municipal Wireless Network](https://en.wikipedia.org/wiki/Municipal_wireless_network#United_States). I’m guessing that might be hardware related to that (if you’re indeed in Honolulu!) ---
**Author:** ![Ashtura](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ashtura/32/2963_2.png) [@Ashtura](https://boards.straightdope.com/u/Ashtura)\ **Post date:** [July 9, 2020, 3:35pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/3 "2020-07-09T15:35:59Z")
It’s a covid 19 emitter. (sorry couldn’t help it). ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [July 9, 2020, 3:54pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/4 "2020-07-09T15:54:35Z")
Given there are already crazy conspiracy theories about 5G wireless networks and COVID, I think it’s best to avoid even joking about such nonsense. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [July 9, 2020, 4:00pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/5 "2020-07-09T16:00:27Z")
Also, [this article](https://www.spokanepublicradio.org/post/pushback-against-superfast-5g-wireless-spreads-least-7-pacific-northwest-cities) from Spokane Public Radio includes a couple of photos of light pole-mounted and utility pole-mounted 5G antennas that look a little like the one in the OP. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 9, 2020, 4:56pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/6 "2020-07-09T16:56:21Z")
Looks like an ordinary “quarter wave” municipal mesh network antenna. The wires extending downward form what’s called a ground plane, which in broadly simplified terms helps with aiming the signal outward rather than wasting most of the power directly under the antenna and/or straight up into the sky. ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [July 9, 2020, 5:10pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/7 "2020-07-09T17:10:32Z")
I can’t tell from the picture, but where does that wire down the bottom lead to? I’m suspecting a lightning protection system. Tripler Does it go to a box, or does it run all the way to the ground? ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [July 9, 2020, 5:42pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/8 "2020-07-09T17:42:03Z")
> [@gotpasswords](#): > > Looks like an ordinary “quarter wave” municipal mesh network antenna. The wires extending downward form what’s called a ground plane, which in broadly simplified terms helps with aiming the signal outward rather than wasting most of the power directly under the antenna and/or straight up into the sky. ~squints~ I think it’s a folded ground plane. The angle of the ground planes have impedence implications as well as the lobe shaping you mention. ---
**Author:** ![pool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pool/32/4152_2.png) [@pool](https://boards.straightdope.com/u/pool)\ **Post date:** [July 9, 2020, 5:44pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/9 "2020-07-09T17:44:56Z")
It’s a fuse cutout. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [July 9, 2020, 10:59pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/10 "2020-07-09T22:59:05Z")
King of looks like an old-timey steam whistle, but I’m pretty sure it’s not one. ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [July 10, 2020, 12:42am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/11 "2020-07-10T00:42:56Z")
> [@pool](#): > > It’s a fuse cutout. I don’t think so. . . I’ve never seen fuse cutouts with spikes protruding from the bottom like that. Plus, it doesn’t look like it feeds through any of the lines. Bag of cheetos says it’s an element of a [lightning protection system](http://4.imimg.com/data4/EO/AC/MY-14093222/ese-lightning-protection-systems-500x500.jpg). Tripler You know I’m good for it. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [July 10, 2020, 1:05am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/12 "2020-07-10T01:05:02Z")
> [@Tripler](#): > > Bag of cheetos says it’s an element of a [lightning protection system](http://4.imimg.com/data4/EO/AC/MY-14093222/ese-lightning-protection-systems-500x500.jpg). Naw, it’s an antenna. Check the similarity with these: > **[Kreco Antennas - Folded Ground Plane Antennas](http://www.krecoantennas.com/fgplane.htm)** > **[WISCO International (CELWAVE - PD128)](https://www.wiscointl.com/celwave/antennas/OmniGround/pd128.htm)** The question is what’s it doing. It’s probably something super mundane like a street light sensor or sewage water level from a pipe below. ---
**Author:** ![pool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pool/32/4152_2.png) [@pool](https://boards.straightdope.com/u/pool)\ **Post date:** [July 10, 2020, 1:49am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/13 "2020-07-10T01:49:21Z")
You might be right I didn’t notice the stuff coming out of the bottom. Cheetos would be good, and what the hell a Mountain Dew ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [July 10, 2020, 1:49am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/14 "2020-07-10T01:49:53Z")
Hrm, I hadn’t seen antennas like those. I retract my wager. That does not seem like a normal place for an antenna though. Tripler Strange. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [July 10, 2020, 2:34am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/15 "2020-07-10T02:34:45Z")
Ham radio operator with a death wish? The antenna looks a bit big for high speed mesh networking, which tends to be in the gigahertz range (and also tends to use directional antennas). For antennas, omnidirectional and big means low frequency. Maybe a repeater for police/emergency radios? Those tend to be in the 150, 450, or 770 MHz bands, which this antenna could plausibly cover (though it’s hard to tell the scale). ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 10, 2020, 1:20pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/16 "2020-07-10T13:20:29Z")
[Moderating] Ashtura, let’s please save the joke answers for after the thread is well underway. ---
**Author:** ![Ashtura](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ashtura/32/2963_2.png) [@Ashtura](https://boards.straightdope.com/u/Ashtura)\ **Post date:** [July 10, 2020, 2:25pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/17 "2020-07-10T14:25:51Z")
Alright got it. ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [July 11, 2020, 3:22am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/18 "2020-07-11T03:22:22Z")
I’m guessing the impedance of the antenna is 50 Ω based on the angles of grounding whips. I’m wondering if this is operating in the 900 MHz ISM band? Because no licensing required. . ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 11, 2020, 11:18am UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/19 "2020-07-11T11:18:41Z")
It’s definitely an antenna. It looks like a folded ground plane (monopole) antenna. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [July 11, 2020, 1:29pm UTC](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828/20 "2020-07-11T13:29:06Z")
Definitely an antenna. As to what it’s doing, there is a whole world of small measurement systems that need to report back to some central office what they’re measuring, more or less in real time. Anything that could need maintenance depending on the measurements (such as a tank that might need refilling), or anything they care about monitoring (such as a stream flow gage), could be serviced with something like this. I’ve used a small yagi beam antenna aimed at a cell tower for this, which relied on cellular service. I was monitoring a superfund cleanup site. [Next page](https://boards.straightdope.com/t/what-is-this-small-antenna-on-top-of-some-telephone-poles/914828.md?page=2)