How To Read An Antenna Chart

Helium is a gateway into the world of RF, or radio frequency. While the easiest thing to do when you get your hotspot is just plug it in and set it in a window, most of the time you’ll earn far more if you optimize a bit. Most of those optimizations are focused on improving the RF signal your hotspot can beacon (also called “transmitting”) as well as improving the ability of your hotspot to witness (also called “receiving”.)

I’ll assume you’ve read the piece on antennas I wrote that covers some basics. Now, let’s do a deeper dive into antennas and radiation patterns.

Let’s start with a zero gain omni antenna. An omni directional antenna with zero gain will theoretically radiate RF energy in a perfect globe pattern all around it. Now, that’s perfection. In reality, most low gain (say, 4 dBi or lower) antennas will do a pretty good job, but will have gaps directly above and below the antenna.

The way we “see” an antenna’s RF pattern is by visualizing what it looks like from the top and the side.

Here’s a lower gain antenna’s RF pattern.

See how it radiates out evenly in every direction to the side, but directly above and below it there are gaps in the RF emitted? That’s pretty typical for an omni directional antenna.

Here’s another example from the antenna I use on most of my installs, the HNTenna. MP Antenna (the manufacturer of the HNTenna), puts both patterns together. The Elevation is what it looks like when you’re seeing the antenna from the side (red line) and the Azimuth is what it looks like from the top down (blue line).

All manufacturer’s will have a radiation pattern for their antenna, and most will share it with you. That pattern can change at different frequencies on the same antenna. Here’s an example of a 3.0dBi L-Com at different frequencies.

Now, all the antennas so far look pretty similar even at different frequencies, right? They’re all “omni directional” antennas, meaning they’re supposed to radiate antenna in all (omni) directions. What does it look like when you get a sector (also called a directional) antenna? Check this out!

This antenna was designed to radiate most of it’s energy in a vertical beamwidth of 60 degrees and a horizontal beamwidth of 70 degrees. This is the antenna you’d use if you wanted to punch through a thick brush line with a bunch of Hotspots on the other side of it and nothing behind you.


Antenna Polarization

Next up is antenna polarization. This hasn’t gotten much press, mostly because damn near every antenna you can buy is polarized *vertically*. In simple terms, that means the RF waves it emit go up and down. A *horizontally* polarized antenna will emit RF waves that go side to side.

Why is that important? Well, if a vertically polarized antenna and a horizontally polarized antenna are trying to beacon or witness each other, they won’t be able to, even if they’re on the same frequency! That’s because the “up and down” waves of a VP antenna won’t intersect with the “side to side” waves of an HP antenna.

OK Nik, so why should I care about this? If most of the antennas out there are vertically polarized, I’m fine, right?” Sort of.

See, when that radio energy hits an obstacle, it usually bounces off *and changes orientation*. That means a vertically polarized wave can now be a horizontally polarized one. If your hotspot is “listening” on a vertically polarized antenna, it won’t witness RF signals that are coming in on the horizontal plane, unless…

Here’s the last twist for ya: You can get a “multi” polarized antenna. This allows you to both transmit and receive multiple signal orientations. That comes at a cost of a slight reduction in power as the signal is radiated out on multiple planes, BUT…I’ve used a multi-polarized antenna and made 170km witnesses, so it’s not an issue in the real world application.

I’ll finish off with a quick way to think about what antenna you should buy.

Indoor antenna — Use the stock antenna. Get it up as high in your building as possible and next to a window. If you MUST buy an indoor antenna, pick up the HNTenna indoor version.

Outdoor antenna, urban area, limited clear lines of sight — You’ve got a few options.

HNTenna Outdoor – This is a multi-polarized antenna and what I recommend for most placements.

McGill 3 dBi – A great omni pattern antenna that’ll do well in most urban deployments.

McGill 6 dBi – Want to try the middle range, as recommended in this video?

Outdoor antenna – Has Facebook/Reddit/Twitter convinced you that high gain is the best bet? If you’re desperate for a “high gain” antenna, get a 9 dBi from McGill.

Brush Penetrator — Ok, you really want this? Keep in mind, this antenna is almost never the right choice. But since you asked for it, here it is.

That’s it! Now you know a bunch more about antenna radiation patterns and how to choose the right one for you. Rock on!

42 thoughts on “How To Read An Antenna Chart”

  1. Hi Nik,

    Is there a 5.8dbi antenna with multi polarisation or 3dbi will be good even for the suburbs where other hotspots are not close

  2. Vis,
    MP Antenna is working on a 5.8 version but it’ll be a while. They’re current antenna will be fine for suburban deployments, just (like very antenna) get it as high as you can.

  3. Hey,
    Quick question, if you already get 25 witnesses on beacon and as high as you can get antenna do different antennas affect witnessing or would that be the same?

    For example with a HNTenna get more theoretical witness events than a 5.8 dbi antenna in an urban setting?

    Just never understood that part. Thanks for the great information!

  4. Hi John, good question. Depending on how many hotspots you have around you, you may see a *different* set of 25 with each beacon. An HNTenna is likely to pick up different witnesses due to the multi-polar receive. I wouldn’t expect miracles, but every small improvement counts.

  5. im currently using a Rak 5.8 in the most optimized way I can given my situation. It appears I’m just on the cusp of a connection w/my neighbor, as we connect, but only rarely. They’re 2.7 miles away. Do you think the 3dbi multi polar might help or should I wait for the 5.8 to be released. Btw, I’ve tried an 8dbi Rak and get nothing as I’m in the foothills

  6. Simon Uxbridge

    Hi Nik,
    I have a location halfway up the side of a mountain (2000ft up), with super long views of civilization and will be using the L-Com flat panel which as you say has a vertical beamwidth of 60, and which you advise to aim carefully. I am looking for points on roughly how to aim it. Would you think aiming the centre of the panel at the horizon would be too high? CIvilisation starts about 1 mile away from me

  7. Pingback: What To Look For In A Helium Antenna - One Man's Search

  8. Hi Nik,

    If you don’t have direct line of sight due to topography, will the hntenna help? Currently using the 6dbi from McGill but that doesn’t work.

    Currently can see witnesses far away, but not in the city nearby.

    https://ibb.co/VJJxb1Q

    Thanks!

    Thanks!

  9. Hi Nik

    I’m looking at a picture of an elevation radiation pattern, almost identical to the HNTenna 915 one above. (I can’t add a picture to this comment.)

    However in this picture the 0 degree point is rotated 90 degrees – so that it lines up with the “dip” in the pattern.

    Could this antenna:
    (1) Simply be the same as the HNTenna diagram (and I’m just overthinking it?)
    (2) Be totally different?
    (3) Or actually be an error in production of the diagram – so in effect the same?

    I hope I have explained this clearly? Many thanks.

    Cheers
    Simon

  10. First responder orgs love those because they’re cheap and they “work”, though they’re definitely not the same antenna as the HNTenna. Remember, antennas don’t really matter that much. Try this one, see if it works for you. For me the cost isn’t a concern and I’d rather have the best on the market, but it *doesn’t make a huge difference.*

  11. Pingback: HNTenna - Is it really the best Helium Antenna? | CoinPensation

  12. Doesn’t have to mention LoRa/IoT/Helium. That’s a huge band the first one is listening on though, and the middle is definitely not 868 so it’s probably not very efficient for what you’re doing. 617 – 3800 MHz, whew!

  13. I have seen a hotspot nearby having a Poynting antenna in it setup.It’s behind a window on the first floor with a LongAP hotspot. It has a beaconing average of 800-900 times (7d avg) and does 2-3+HNT per day. I was not sure if the poynting antenna was used for the miner or maybe a LTE router/modem. If used for the hotspot the MiMo technique seems help picknick up a lot of signals.

  14. Interesting, I’ll check out the Poynting. What’s the hotspot name? Transmitting 8-900 beacons in 7 days is way over the top, you sure that’s not witnessed beacons?

  15. Hi, not much info about Hntenna , you ordered, all is fine ? with new POC i think this antenna might be a good option, a bit scared to order, I would appreciate it that you confirm if they are legit?

    thanks

  16. Hi Jeff, I’ve ordered and deployed multiple HNTennas. I think they’re the best on the market, and an excellent option for most hotspots deployments. High quality, made in Ohio, I’ve been to their manufacturing plant and met the staff.

  17. Hey Nik,
    Any idea how a standard vertically polarized antenna would function if you mounted it at a 45 degree angle to the ground? Would it then function as a multipolarized antenna since the waves would be transmitting and receiving (in theory) partially both vertical and horizontal waves and everything in between? I’m sure that as an antenna’s RF is bouncing around the world it’s not purely vertical even if it’s coming from a vertically mounted antenna, and as you mentioned, it seems that in the real world barring your antenna being in a very flat environment, it seems that RF would be bouncing and bending all over the place the further it got from the antenna and thus would be able to be picked up by an antenna mounted at 45 degrees.

    Also any idea how ground planes affect a vertically polarized antenna? There’s a guy on reddit talking about how he mounted his 4dbi bobcat antenna on a bread pan and it increased his earnings and other people said they tried it and it increased theirs too. I wonder if a ground plane is making the vertical waves at least partially multipolar and thus allowing these antennas to perform better?

  18. Hi Brad, it would probably function worse. Multipolarization is about multiple angles. For the Bobcat, testing in an RF chamber has shown that a metal plate at the bottom improves antenna performance.

  19. Great info on the patterns. I have 2 situations I’m where I’m considering the HNTenna and I could use some advice on.

    1. Prairie town, I have the high side about 60’ higher in elevation than the rest. 7-9KM to the furthest hotspots. Maybe 60-70 in the area and I witness about 30 with a Rak 5.8 on the peak of my house – 500 yards from me sits a giant brick school though. 3dbi Outdoor Hntenna going to provide any benefit?

    2. Host location lower plane of the same town but restricted to indoor only with some line of sight challenges and using a Bobcat stock 4db – Hntenna indoor 3dbi claims it’s good at overcoming some of these challenges – thoughts?

    Have no issues spending the $ to find out but McGill is also in my considerations..

    Thanks,
    Mike

  20. Hi Mike,
    Always hard to say that one antenna will always do super well. I’m putting HNTennas up even on my mountain installs now. I don’t think you’ll see a huge improvement over the Rak, though you may see a slight one. The HNTenna indoor is supposed to be excellent, but I haven’t installed it indoors. I’ve seen it work well outdoors. You won’t go wrong with any of those antennas listed.

  21. Hi Nik,

    Trying to understand if a directional antenna is beneficial over a omni-directional for a situation where the witnesses are only on one side (180 degrees of hex). I would think an 8dBi directional antenna would reach as far as a 8dBi omni-directional antenna but for only a few degrees. Is this the case or will the directional antenna see further?

  22. Depends on where you are. In the US there’s not a huge advantage with directionals. In the EU it may make more of a difference, all because of how much more dBm the US hotspots push out.

  23. I’m wondering…
    If I mount an antenna on my roof near the peak, does it make a difference if only the top of the antenna is above the Ridgeline, or should the full length of the antenna be above the ridgeline? Our HOA doesn’t allow mounting an antenna on the roof, but if I mount it with only the tip above the ridgeline, I might be able to get away with it.
    I ask because I don’t know if the antenna sends/receives only from the tip or the full length.
    I’ve tried reading everything on your site but cannot find information concerning the tip of the antenna vs. the length of the antenna. Thanks in advance if you choose to answer.

  24. Hey Nik,
    Question for ya. I’ve got the choice of mounting an antenna out my window, 3rd story townhouse so approx 9 to 10 meters high mounting point, that faces towards the majority of Hotspots or placing it in the attic space, approx 2 to 3 meters higher than out the window. Not possible to mount on roof due to strata. Suburban area with a not so bad line of sight other than a giant church directly across the street. Any recommendation as to which mounting point and whether a 3dbi or 6dbi would be best?

  25. What panel antenna are you using on the pictures? I seen many pictures that showcase a panel antenna. Thanks

  26. Hi Robert, I’ve used both 9 and 13 dBi antennas in various test deployments. I have one 9 dBi panel left that I just haven’t replaced because I haven’t made the time to drive over to it.

  27. Hey Nik, 2 questions.

    I currently have a 12 foot lmr 400 attached to a 8dbi antenna. If I wanted to go 30 feet high with lmr 400 and stick with 8dbis worth of signal do I go with a 10dbi because of the signal loss?

    Also a miner just popped up in my hex 🙁 he is still syncing, my rewards are already tanking is there anything I can do or just make my antenna set up significantly better?

    Thank you!

  28. Nah, don’t worry about offsetting with an 8 dBi and only 30′ of LMR400. Enter the loss (about 1.4 dB) and let ‘er rip. Nothing you can do about other miners in your hex (outside of filling in surrounding hexes to increase to density_max OR moving.

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