Helium Hotspot Antenna Upgrade Guide – 8dbi vs 5.8dbi vs 3dbi – Which cables & connectors to choose to reduce signal loss?

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Update – I have updated this content to be more clear about the effective range.

I have previously written a post on upgrading my Helium Hotspot with the MikroTik LoRa 6.5dBi Omni Antenna.

Since then, I have made a lot of changes, obsessing about finding the best performance. Sadly my performance has dropped due to a large number of hotspots in my town. I wish I had used the optimal set up from the start.

It turns out antennas are more complex than you think. It is not just a case of buying the most powerful one you can find and placing it as high as possible.

8dbi vs 5.8dbi vs 3dbi Antenna – Different antenna gains have different degrees of coverage

Update – My original explanation below is not very clear and a bit misleading. The above diagrams show the effective range on the verticle plane, so the 9dbi has a sort of pancake or doughnut-shaped coverage pattern, while the 2dbi is a perfect sphere capturing everything around it.

This is why a lot of people choose to use something around 5dbi or 6dbi because this will offer a good balance of range and being able to connect to nearby antennas at different heights as yours.

Omnidirectional antennas are not quite as omnidirectional as you think when you increase the antenna gain. So you can’t just buy a Taoglas Barracuda 12dBi antenna and think it will cover a huge distance with 360-degree coverage – trust me, I tried, and it is a super expensive antenna.

The lower the gain, the better the coverage, at 2dbi, you get 360° coverage, but at 5dbi, it drops down to 40° then 7dbi is 30°.

So in a city with a lot of hotspots around, you might be best off with a lower gain antenna.

Then, of course, is the placement; higher with fewer obstructions is better, obviously. In hindsight, I wish I had paid to get an aerial company to come around and fit my antenna on my chimney.

Also, remember, you will need an antenna that is compatible with your specific region. Some antennas cover multiple frequencies, which is fine, as long as it covers your frequency.

  • For the UK this is 868Mhz
  • For the US this is 915Mhz

Helium Hotspot Antennas for the UK 868Mhz models of the Helium Hotspot

Be warned, the Taoglas 12dbi option is not likely the best choice unless there are not many hotspots near you.

I wouldn't personally buy from Nebra anymore, the way they have dealt with the Helium Hotspots is poor. But the below antennas are still worth considering. I personally use the Paradar 8.5dBi which I reviewed here and is available on Amazon.

Helium Hotspot Antennas for the US 915Mhz models of the Helium Hotspot

Signal loss through the cable

You also need to consider how the signal degrades on the way back from the antenna to your hotspot. The longer the cable, the bigger the signal loss. Again, in hindsight, I messed up here, buying cheap cables on Amazon.  Similarly, if you use the SMA adaptors you buy on Amazon, you can potentially introduce further signal loss.

You can get low loss cable, Amazon has lots of these listings, but a decent low loss cable is LMR-400 which is harder to find and much more expensive.

Just be warned, the LMR-400 is very thick, I had an old hole coming through into my office for a TV antenna, and I only just managed to squeeze it through. I had previously run cables through a small window, leaving a small gap with the window partially closed, but this cable would have left a huge gap.

Custom cable and which connectors to use on your antenna  

Antenna with N-Type connector going to RP SMA MALE

You can get cable made up to custom lengths, this will be your ideal option allowing you to select the minimum length required to reach your hotspot.

To avoid using adaptors, you will need to work out which cable end you need. For the MikroTik LoRa 6.5dBi Omni Antenna I use, it has an SMA female end while the Helium Hotspot has an RP-SMA Female .

So for the MikroTik, I needed the opposite connectors, which are RP SMA MALE (Helium hotspot side) to an SMA Male (Antenna side)

I ended up buying off  McGill Microwave Systems on eBay. I think it was this cable but then I messaged them asking for the RP SMA MALE & SMA Male cable ends.

Some antennas use the larger N-Type Male connection, this includes the RAK 5.8dbi Fiber Glass Antenna Kit, so this would require a N-type female 

If you get a cable made up I would suggest confirming with the company the exact ends required, I get easily confused with all the connector types and it is easy to get mixed up. A professional will know best.

Some of the options on Amazon are available below, but you may need to buy the adaptors to fit things properly.

Last update on 2021-09-16 / Affiliate links / Images from Amazon Product Advertising API

9 thoughts on “Helium Hotspot Antenna Upgrade Guide – 8dbi vs 5.8dbi vs 3dbi – Which cables & connectors to choose to reduce signal loss?”

  1. Hi thank you for this as it is informative, but can I make one additional note. An antenna works on both horizontal and vertical planes. What you highlight which is right, is the he higher the gain of the antenna it reduces propagation on the vertical plan, but still provides 360 degrees on the horizontal plane.

    What this will mean is that you are likely to send or receive signals to or from further away but will miss the ones that are close by you. Therefore as you mention above you need to decide wisely in the case of a miner to which will provide you the best coverage.

    There is a whole science around antenna’s which I admit not to a specialist picked up enough to do a radio course some time ago but thought it would help to support your article.

    Reply
      • Hi bro,
        I have 2 questions:
        1) I live in area where near hotspot is 4km through air in the map so should I go with 3dbi or more dbi antena?
        2) if 8dbi antena which cover 25° range and not 360° how do I know which way to point the antenna on the city area where are the hotspot so I cover the 25° range? is there some point marked on the antenna how should we point it?

        thx

        Reply
        • I’d probably go with the 8dbi.

          I thought I had updated this post to be more clear about the effective signal, sorry. My information is slightly confusing, the effective range is on the verticle plane, so if you look at the diagram the antenna drawings are verticle as you would mount them. Therefore the 9dbi will achieve further distance but there is a good chance it will not pick up on hotspots closer by if you have positioned the antenna too high or low. So it is still 360-degrees but the effective area is more a flat doughnut shape rather than a ball.

          So a high-density area is best off with the lower gain antennas ensuring you connect to everything close by, while sparsely populated are best off with high gain.

          Reply
  2. Hi, this is a great review of the Helium Hotspots.

    I’m in the UK and have a Bobcat Miner and RAK V2 on the way. Can you confirm which antenna upgrades you would say are best to be placed outdoors on the roof?

    Thanks in advanced.

    Reply
  3. I enjoyed your post. The links to the right cabling for upgraded hotspot antenna will prove useful. I am still on the lookout for a comparison table of the antenna that are shipped by default with a hostspot. This would help me identify the brand of my neighbours hotspots. Which out performs my own although being at a lower elevation and lower dbi !!

    Reply
  4. Great post thanks very much. Could have two miners on the same wifi router but both 300 meters apart in separate hexagons? Will this work? Just a thought.

    Reply

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