What’s The Best Antenna For Your Helium Hotspot?

Here is a step by step method for under­stand­ing how to choose the best anten­na for your hotspot place­ment. Each place­ment demands a well matched anten­na in order to pro­vide val­ue to the Heli­um Net­work and con­se­quent­ly earn the most HNT pos­si­ble for that loca­tion. Do NOT, by the way, try to get the giant anten­na in the pic­ture below. While it looks huge and cool and rad, it is the wrong anten­na to use for these deploy­ments. I spent a fair amount of blood and trea­sure to learn that les­son. You don’t need to. 

First: Hotspot place­ment opti­miza­tion is FAR more impor­tant than what anten­na you use, more on that here.

Sec­ond, for those of you who just want AN ANSWER: Sim­ple: Pick from the McGill selec­tion. They’ll all work well. 

Put it out­doors at least 10′ above all the build­ings around you. Run 40′ or less of LMR400 cable to it from your hotspot. If you have to go more than 40′, use LMR600 if you’re feel­ing extrav­a­gant. That’ll prob­a­bly get you 80% of the results you could get with far more effort and expertise. 

Wait, you want to actu­al­ly learn and match your anten­na to your sit­u­a­tion so you get the max­i­mum rewards possible?

Ok, let’s start with broad strokes: The anten­na you choose for your hotspot place­ment should match your topog­ra­phy, your ele­va­tion, and your lines of sight.

Let’s start with topog­ra­phy. Topog­ra­phy refers to the build­ings, earth, and water that sur­round, chan­nel, and block your radio sig­nals (prop­a­ga­tion.) The top­ic of radio prop­a­ga­tion involves a tremen­dous­ly deep dive all the way down to the fun­da­men­tals of physics, but we’ll keep it pret­ty simple.

BLUF (Bot­tom Line Up Front) — The flat­ter your topog­ra­phy AND the more trees/vegetation you have block­ing your Line of Sight to oth­er hotspots, the high­er gain anten­na you can use, up to 9 dbi.

Remem­ber, topog­ra­phy isn’t just hills and moun­tains, it includes build­ings, trees, and oth­er obstacles. 

Ok, let’s get dirty! In gen­er­al, earth in the form of moun­tains or hills will block radio sig­nals. Even though a hotspot may seem very close to you, if there’s a hill between the two of you, you prob­a­bly won’t wit­ness each other.

You may check out your loca­tion on the Heli­um Explor­er Cov­er­age map and think you’re per­fect­ly posi­tioned in regards to near­by hotspots, like this:

Remem­ber to check Google Earth!

See how that spot is tucked into a bunch of hills? Unless you put up an anten­na that’ll stick over the top of the hills, you’re restrict­ed to wit­ness­ing only oth­er hotspots in your imme­di­ate area, and in this case, that area is small!

One of the best tools to use when assess­ing a new site is Heli­umVi­sion. Remem­ber, loca­tion is FAR more impor­tant than anten­nas. If you’d like to learn more about Heli­umVi­sion (I use it in every one of my con­sults) I’ve built a Mas­ter Class on it, over here.

Ok, so that’s earth. Earth = No Radio Waves Get­ting Through.

What about build­ings? How much will build­ings block or reduce the pow­er of radio propagation? 

Accord­ing to a study done in 2012 on a wide swath of build­ing mate­ri­als and focus­ing on the GSM 900 MHz band, a rein­forced con­crete wall that is 20cm / ~8″ thick will atten­u­ate the sig­nal by 27 dB. An inte­ri­or plas­ter wall will reduce pow­er by any­where from .8 to 3 dB.

What does that mean? Dis­claimer: RF geeks, I’ma get loose with terms here. Relax.

This reduc­tion in pow­er is called “atten­u­a­tion.” In gen­er­al with radio com­mu­ni­ca­tions, you don’t want any atten­u­a­tion. Atten­u­a­tion can hap­pen with earth, build­ings, forests, and even win­dow coat­ings. How much pow­er will you lose? Let’s run some numbers.

Amer­i­can based hotspots start off by push­ing out 27 dBm. Euro­pean and oth­er areas start WAY low­er, at 14. Add the gain (dBi) from your anten­na and sub­tract the loss­es from any con­nec­tions to fig­ure out your Effec­tive Isotrop­ic Radi­at­ed Pow­er (EIRP).

That means a 6 dBi anten­na will give you 33 dBm of EIRP with a US hotspot. 27dBm + 6dBi = 33dBm in the direc­tion of anten­na gain. Now you’ve got to cal­cu­late cable and con­nec­tion loss.

As a rough rule of thumb, each con­nec­tion (hotspot to anten­na cable, anten­na cable to anten­na, or going through an enclo­sure wall using a con­nec­tor) will drop your EIRP by .5 dB. Cable loss­es vary by cable, which is why most peo­ple use a “low loss” cable like LMR400. If you want to run your EIRP num­bers, here’s how.

Ok, ok, ok, why does it mat­ter whether or not you know your EIRP? 

Let’s take a short detour into dBm and pow­er. dBm is based on a log­a­rith­mic scale. For every increase of 3 dBm, there is twice as much pow­er out­put. Every increase of 10 dBm has a ten­fold increase in pow­er. The dif­fer­ence between a 3 dBi anten­na (what most hotspots ship with) and an after­mar­ket 9 dBi anten­na is a fac­tor of 4! 

Of course, that 4x pow­er comes at a cost; the beam is focused; more laser and less light­bulb. That means that unless you aim your anten­na very care­ful­ly, you can blast all that pow­er into places that have no hotspots.

Here is a great exam­ple demon­strat­ing atten­u­a­tion and topog­ra­phy. This hotspot is placed on the north side inside a build­ing. It’s up high with a high­er gain anten­na, and in gen­er­al, inac­cu­rate­ly aimed over most of the near­by hotspots.

Most of the wit­ness­es it’s get­ting are fur­ther north. Some of the sig­nals bounce off to the side, prov­ing that “RF is weird.” 

To the south, the sig­nals are blocked or atten­u­at­ed by inte­ri­or and exte­ri­or walls, but appar­ent­ly there is a small win­dow or open­ing where those weak­ened sig­nals are escap­ing, then going pret­ty far over the water. Pret­ty neat, right? I mean, not for the hotspot own­er, but it’s a neat demon­stra­tion of the concept.

That image is also a great exam­ple of why you should nev­er put a hotspot anten­na inside; you are los­ing a ton of pow­er before the radio waves ever get out­side the building.

Water allows radio sig­nals to trav­el much fur­ther than nor­mal; look at any hotspot next to a body of water and you’ll see it will con­nect with oth­er hotspots at much fur­ther ranges across the water than it will across land. 

Let’s not get too into the weeds here. As I said at the begin­ning, the gen­er­al rule for topog­ra­phy is this: The flat­ter your topog­ra­phy, the high­er gain anten­na you can use, up to 9 dBi for 95% of place­ments. Beyond 9 the pat­tern gen­er­al­ly gets too pre­cise to pro­vide the Wide cov­er­age (the W in WUPU) that we want.

Remem­ber, topog­ra­phy includes not just hills, moun­tains, and water, but all the build­ings, bridges, and oth­er struc­tures that might block your radio sig­nal. Cities in gen­er­al do not have a flat topog­ra­phy, even if they’re built on flat land. All those spiky build­ings stick­ing out will gob­ble up your radio signals.

That brings us to ELEVATION. If you want to bend your mind a lit­tle bit, think about this: The high­er your ele­va­tion, the flat­ter the rel­a­tive topog­ra­phy is, and the LOWER dbi anten­na you can use. Wait, what?

Remem­ber, a high dbi anten­na focus­es the sig­nal of your anten­na. In an omni anten­na (we’ll get to direc­tion­al or sec­tor anten­nas in a minute), that shape becomes a flat­ter and flat­ter plane. If that plane is super flat, it’ll fly right over the tops of all those hotspots you want to hit. Let’s go through 3 examples.

Now, those aren’t how it *actu­al­ly* works. The gain pat­terns are nowhere near as dif­fer­ent, and a high gain anten­na will STILL hit the ground with­in 1,000′ of even a 100′ build­ing. Still, you can see why in *most* cas­es, you want a low or medi­um gain anten­na up high.

You can also run that idea back­wards; if you’re in a real­ly flat area where you don’t have a lot of obsta­cles, a high gain anten­na might be your best bet. Still, most peo­ple don’t live in the desert, and the flat­test state in Amer­i­ca has a ton of trees on it. If that’s your sce­nario, get a high gain (6–9 dBi) anten­na up over the tops of those trees for max­i­mum coverage. 

That brings us in a round­about way to Lines of Sight. Remem­ber that $39 paper I quot­ed ear­li­er regard­ing how much RF ener­gy a giv­en build­ing mate­r­i­al would absorb? The gen­er­al take­away for us Heli­um Hotspot own­ers is this: Our anten­nas won’t blast through much more than 2 build­ings.

That means if you’re INSIDE the build­ing, you’ve burned most of the ener­gy of the anten­na just get­ting out­side the walls. If it hits just one more “thing”, whether it’s a build­ing, a tree, or a bill­board, that’s prob­a­bly the end of the line.

This “Lines of Sight” idea has an impor­tant impli­ca­tion in under­stand­ing how some of the top earn­ing hotspot/antenna com­bos are doing so well. The hotspot Docile Bone Pony* (when this was writ­ten, one of the high­est earn­ers in the world) is on top of a 16 sto­ry build­ing in a major city with a medium/high gain anten­na (8 dbi from eBay on 60′ of LMR400.) It has Lines of Sight to a lot of oth­er hotspots, BUT those oth­er hotspots don’t have great lines of sight to oth­er hotspots around ’em.

That means that DBP is see­ing a lot of hotspots that AREN’T see­ing a lot of hotspots. I’m going to anthro­po­mor­phize this a bit, but their only option is to com­mu­ni­cate with DBP. So they do. And DBP earns like crazy. It’s an exam­ple of the incred­i­ble earn­ing poten­tial that exists when pro­vid­ing asym­met­ric val­ue to the network.

While we’re on Lines of Sight, let’s talk about the range of a stan­dard hotspot. Accord­ing to some excel­lent work done by the inim­itable @para1 on Dis­cord, most hotspots do most of their wit­ness­ing with­in a 10km range. Now, an in depth dis­cus­sion of the impli­ca­tions and restric­tions of this table is beyond the scope of this arti­cle, but your gen­er­al take­away should be “Opti­mize your anten­na for hot­pots with­in 10 km” aka most peo­ple don’t need a high gain antenna.

I’ll dou­ble tap this range thing with an exam­ple of a hotspot I run, which has a 3 dBi HNTen­na on top of a 20′ pole on top of a ~30′ build­ing. It *rou­tine­ly* gets wit­ness­es over 200km away. While it seems that a high gain anten­na will get you bet­ter range, it does­n’t real­ly mat­ter. It’s Line of Sight that is the secret here.

Final­ly, Lines of Sight can be blocked by forests. Depend­ing on who you lis­ten to, LoRa does­n’t go through much more than 60 meters of dense for­est. I’m sor­ry rur­al Flori­da, you’ve just got a tough row to hoe on that one. Dense for­est in between you and oth­er anten­nas is about the only time a high­er gain (up to 9 dBi) makes sense, and even then it may not make a giant dif­fer­ence. Forests are RF sinks.

There is one more thing to think about with Lines of Sight. The 900 MHz fre­quen­cy needs some run­way, ide­al­ly 50′/15m to fan out enough to dif­fract around obsta­cles. Read that again and you’ll have an advan­tage over every­one who does­n’t get that concept.

The con­cept of Fres­nel zones and dif­frac­tion in radio wave com­mu­ni­ca­tion is one of the fun­da­men­tal dri­vers of the “RF is weird” refrain you’ll hear when­ev­er you see a pat­tern that does­n’t imme­di­ate­ly make sense. Basi­cal­ly, the fur­ther out your radio waves go, the more they can spread out along their radi­a­tion pat­tern, the less like­ly that all of the waves get blocked, and the more like­ly that at least some of ’em will get to anoth­er hotspot. 

At some dis­tance they’re so spread out that you’re basi­cal­ly not going to make a con­nec­tion, so the effec­tive “win­dow” shrinks back down. Like this:

If you set up your anten­na so that you’ve got lots of clear space around it before it hits obsta­cles, those radios waves have enough spread to start “bend­ing around” those obsta­cles. This is yet anoth­er rea­son not to set up inside. 

Here’s anoth­er “I def­i­nite­ly did­n’t go to art school” draw­ing to demon­strate the idea of run­way and diffraction.

If you give those radio waves some room to spread out, they can get around obsta­cles. Let ’em breathe!

Ok, we’ve got one more thing to con­sid­er before wrap­ping up. Many of you will have been scour­ing ham radio sites to fig­ure out how to improve the range of your anten­na. Keep in mind that the goal of many ham radio oper­a­tors is incred­i­ble range, but that can come at the cost of broad cov­er­age. Doing exact­ly what a ham oper­a­tor does may give you the results they want, not what you want.

YOU want to hit as many high scale hotspots as pos­si­ble. You’ll usu­al­ly do that by using a low gain anten­na up high, with clear lines of sight all around.

Remem­ber, you’ll earn the most by deliv­er­ing the most valu­able & prov­able cov­er­age to the net­work. The con­cept is sim­ple. The exe­cu­tion can be com­pli­cat­ed. If you want help with get­ting the max­i­mum val­ue out of your place­ments or strat­e­gy, I’m avail­able for hire.

For those of you who skipped all that and just want to know what anten­na to get, here are 4 gen­er­al­ly good options for the 3 most com­mon scenarios.

1. In a build­ing in the city? Get an out­door HNTen­na or a McGill in the 3–6 dBi range, put it out­side up as high as you can.
2. In a build­ing where you just can’t get up high? Use the stock anten­na that came with your hotspot. Also, find a bet­ter place­ment loca­tion. You did read about that, right?
3. In a sub­ur­ban house? Get either the HNTen­na or a McGill in the 3–6 dBi range and put it on a pole out­side and up high.
4. On a moun­tain where you can’t pos­si­ble trans­mit behind you (because the moun­tain will block your sig­nal) and you have an enor­mous view of civ­i­liza­tion and your near­est hotspot is more than 5 miles away? Try a 8–9 dBi patch anten­na, like these.

I’ll round this out with what to def­i­nite­ly NOT do. Don’t just look at the gain of an anten­na and think high­er is bet­ter. Don’t both­er with Yagi anten­nas. Final­ly, don’t wor­ry too much about your anten­na. In the big pic­ture of earn­ings, it is FAR more impor­tant to have good place­ment and ele­va­tion. The fan­ci­est, coolest, most high tech anten­na in the world won’t get you much if you’re in a crap­py loca­tion down low.

Best of luck with your place­ment and earn­ings, I’m stoked to be a part of this amaz­ing com­mu­ni­ty! If you’re look­ing for work in the Heli­um ecosys­tem, check out  Heli­um Jobs. You can post and find jobs there, help sup­port the ecosys­tem by mak­ing it eas­i­er to con­nect pro­fes­sion­al­ly, and let the world know that YOU exist and want to help con­tribute with­in the Net­work. Rock on!

Resources and Further Reading

A deep­er dive into under­stand­ing how RF works.

Cal­cu­lat­ing RF Pow­er Val­ues (explains why a 6 dBi anten­na dou­bles your power)

900 MHz: The Wire­less Work­horse. (Prob­a­bly why Heli­um chose LoRa)

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List of Helium Hotspots & Their Antennas

Before you read this and assume that you must have a high gain anten­na in order to get great earn­ings, please keep in mind that these hotspot own­ers are gen­er­al­ly tin­ker­ers and often have some exper­tise in RF the­o­ry. The results are a lit­tle skewed because of that.

UPDATE: Heli­umVi­sion now reports this for all hotspot own­ers who have entered this on Heli­um app. I’ve closed sub­mis­sions on this page. 

Docile Bone Pony — Ele­va­tion: 16 sto­ries, Area: Greater Boston, MA. Anten­na: 8 dbi omni from eBay, Cables: 60′ of LMR400

Sweet Sage Pike — Ele­va­tion: 43′ above ground, Area: San Diego, CA. Anten­na: Near­son 9, Cables: 5′ of LMR400

Chilly Blood Mon­goose — Ele­va­tion: 41′ above ground, Area: San Diego, CA. Anten­na: Laird FG9026 (6 dbi), Cables: 5′ of LMR400

Lucky Men­thol Wasp — Ele­va­tion: 60′ above ground, Area: San Diego, CA. Anten­na: RAK 5.8 dbi, Cables: 11′ LMR400

Nice Lip­stick Chim­panzee — Ele­va­tion: 25′ above ground, Area: San Fran­cis­co, CA. Anten­na: RFMAX | ROSA-900-SNF, Cables: 5′ LMR240

Inter­est­ing Pearl Star­ling — Ele­va­tion: 35′ above ground, Area: North Shore, MA. Anten­na: RAK 5.8 dbi, Cables: RAK pig­tail inter­face con­vert­er bun­dled with antenna

Jumpy Iron Fer­ret — Ele­va­tion: 34th sto­ry, Area: Chica­go, IL. Anten­na: Stock, Cables: N/A. Indoor setup.

Kind Infrared Lynx — Ele­va­tion: 15′ above ground, Area: Den­ver, CO. Anten­na: Tao­glas 8 dbi. Cables: 15′ LMR400

Lucky Dijon Scal­lop — Ele­va­tion: 33′ above ground. Area: Engle­wood, CO. Anten­na: RAK 8 dbi. Cables: RAK pig­tail cable

Sticky Pear Dol­phin — Ele­va­tion: 311′ above ground (moun­tain). Area: San Fran­cis­co, CA. Anten­na: Oukeione 3 dbi. Cables: Bingfu

Petite Men­thol Leop­ard — Ele­va­tion 25′. Area: Napa, CA. Anten­na: 5.8 RAK. Cables: Bingfu

Best Tan­ger­ine Racoon — Ele­va­tion: Sec­ond Floor Win­dow. Area: Bay­onne, NJ Anten­na: Stock 3 dBi Cables: 1m pigtail

Warm Juniper Pan­ther — Ele­va­tion: 4th floor rooftop. Area: Bay­onne, NJ Anten­na: Near­son 9 dBi. Cables: 4′ LMR400

Scrawny Egg­plant Pan­da — Ele­va­tion: 35′ Area: Lake­wood, OH Anten­na 4 dBi Mul­ti­pole Cables: N/A

Ancient Cider Grasshop­per — Ele­va­tion: 40′ Area: Kansas City, MO Anten­na: RAK Wire­less 8 dBi Cables: 30′ LMR400

Oblong Slate Platy­pus — Ele­va­tion: 400′ Area: New York City, NY Anten­na: Prox­i­cast 10 dBi Cables: LMR400

Ripe Banana Gob­lin — Ele­va­tion: 2nd floor win­dow Area: Van­cou­ver, BC Anten­na: Stock 3 dBi Cables: N/A

Trendy Rain­bow Lizard — Ele­va­tion: 1st floor win­dow Area: Van­cou­ver, BC Anten­na: Stock 3 dBi Cables: N/A

Striped Pewter Osprey — Ele­va­tion: 20′ Area: Los Ange­les, CA Anten­na: RAk 5.8 Cables: LMR400

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