Short version: Use a low gain antenna, report your location and antenna gain accurately. If you’re in the US, this isn’t a big deal, as our radios pump out enough power to get excellent range even with a low gain antenna. If you’re in a region (UK, EU, etc) where your radio output is low, PoCv11 will probably decrease your range significantly.
Updated Deep Dive over here.
Want to read on for posterity? Cool!
PoCv11 is designed to help the Network more accurately assess location from radio frequency strength signals and to keep Hotspots in RF regulatory compliance. It cleans up a few mistakes Helium made early on in trying to assess radio signal strength in an attempt to combat gaming.
That’s it. If you are accurately reporting your antenna gain and your location, there’s no penalty and nothing else you need to do.
Normally I love to explain complicated things, but this one is so damn simple it’s hard to do better than Amir Haleem, CEO at Helium:
i’ll try and summarize what PoC V11 does:
adds regional support for PoC – today the network treats all PoC activity as if it’s operating in the US. this is a problem as different regions run on different radio frequencies and at different power levels (by law), so what is considered valid or invalid varies substantially. V11 adds regional awareness based on the asserted location of the Hotspot
removes SNR from the validity checks – today both the signal-to-noise ratio and free space path loss calculation (FSPL) is used to determine whether PoC packets are valid or not. this was an attempt to make it more difficult for gamers to lie about their location. it hasn’t worked well and is being removed. SNR proved to be fairly useless as a mechanism, so now only an FSPL calculation is used to determine whether Hotspots are where they say they are in relation to each other
adds a regional frequency check – V11 introduces a check to make sure that PoC packets are being sent at the correct frequency for the region the Hotspots are located in. for example if a Hotspot is transmitting packets in the US frequency bands but based in South Korea, those packets would now be invalid
complies with local power output regulations – different regions have different maximum power output laws for unlicensed radios. in the US, for example, the max EIRP is 36dBm. in the EU this is 16.5dBm. currently in PoC v10 the power output is hardcoded to 27dBm for the US and rest of the world, and 14dBm for the EU. V11 will reduce the power output if the combination of the maximum output power + antenna gain exceeds the local laws – for example, a Hotspot operating in the US with a 5.8dBi antenna would have a total EIRP of the Hotspot power output (27dBm) + the 5.8dBi antenna = 32.8dBm total EIRP, which is below the 36dBm allowed. nothing would change in this case. if instead the antenna was changed to a 10dBi antenna bringing the total EIRP to 27dBm + 10dBi = 37dBm, the miner software will reduce the power output of the Hotspot by 1dBm so that the total is less than equal to the 36dBm allowed by law. in the EU a 5.8dBi antenna would cause the Hotspot power output to be reduced to 10.7dBm so that the total EIRP is 16.5dBm
PoC V11 does not have anything to do with the 10 witness maximum, or the witness randomization changes that were added recently. we’re hoping to activate PoC V11 in early October. it is currently not active.
But, but, but, it COSTS MONEY to state my antenna gain! Relax, dawg. It costs 55,000 DC. That sounds like a lot. It’s not.
1 DC = $. 00001. So, 55,000 x .00001 = $.55. You can afford that.
I know you want to get all worked up about PoCv11 and how it will change things. Relax, it’s not a big deal as long as you’re playing by the rules. It’s part of Helium’s efforts to improve the network. Color within the lines (report your location, antenna gain, and elevation accurately) and PoCv11 will only make things better.
That’s a reasonable assumption, though I bet people will be driven more by earnings than invalid warnings. 😉
In the UK and I just got my miners. Looking around me the reward has dropped drastically. I also have 2 bobcats which I may not get to use.
Is there any point getting any better antennas? I was thinking to use a 12dbi inside the loft and another 4 to 6 dbi outside mounted on the chimney, this would be with 2 different hotspots, or maybe one in the back garden, but won’t be doing much for distance, maybe 50 meters max.
Or just stick to 1 hotspot. if so which way? In the loft with a stronger antenna and removing around 5dbi from it? Or the external one of 6dbi or 4dbi and reporting it like you suggested at -1.4dbi.
One hotspot per location is best practice. External antennas almost always outperform ones indoors. Remember to report the EIRP, not actual cable loss. So, ANTENNA GAIN minus CABLE LOSS is what you enter into the app.
If you had a 6 dBi antenna with 1.2 dB of cable loss, you’d report an antenna with a 4.8 gain. Does that make sense?
Hi Nik,
Thank you for all your great support to the Helium community!
I think I read somewhere that you used to like patch/directional antenna but not after the inroduction of PoCv11. Is that true and if so why is that?
Thanks a lot!
Patrick
Actually, the other way around. Prior to PoCv11 they were very difficult to get to work well because you had to offset the gain. With PoCv11 in place you no longer get penalized by the additional gain. Still, you’re almost always better off with an omni anyway, so there’s not a huge point in using directionals.
As far as TRANSMITTING is concerned:
In Dutch regulations I see 25 mW ERP which is 14 dBm ERP, which corresponds to 16.15 (not 16.5) dBm EIRP.
EU CE certificate for Bobcat miner 300 2 GB EU version says LoRa RF power is 9.90 dBm ERP.
So I would argue 14 – 9.90 = 4.1 dBm is the maximum nett antenna gain, including losses caused by cable, connectors and lightning arrestor, if I dont want my TX power to be reduced by PoCv11.
As for RECEIVING:
For RX a high gain could still be interesting, right? If the majority of your earnings come from witnessing (and not from beaconing) than you might consider using a higher antenna gain and accepting the possible reduction of beaconing, as long as you maximize your earnings by witnessing more other hotspots.
And then of course there will be people specifying lower antenna gain then they use in reality, as long as they don’t get invalid witnesses. To have “best of both TX and RX worlds”.
Since I try to really clear this up for myself, I was curious where you found the 16.5 dBm EIRP for Europe.
Thanks!
Hi Jacobus
Great question & observation, sounds like you know about this than I do. 🙂
I’ll have to dig around for the 16.5 number, that came from Amir Haleem’s quote. I found the EIRP on page 27 of the LoRa-Alliance LoRaWAN Regional Parameters document. “By default, the Max EIRP is considered to be +16 dBm”.
If you find anything else I can improve, please let me know. Thanks for bringing this up!
Hello Nik!
Quick question or your opinion: if our current HEX is already occupied will it be worth it to place (on the app not actually) the miner on the next HEX which is empty!? The distance is 250m from the actual location..
Thanks in advance 🙂
Hi John,
The official line is that you should assert the location where it is. My take is that mis-asserting your Hotspot is fine within, say, 150 meters for privacy reasons. You can certainly test it out beyond that. Make sure you’re checking all res and not just 8.
Hey, for example if I have 7.5 antenna and my tottal los brings me to 5.8 dbi, should I add 5.8 into application or put 3dbi in order to avoid limiting my power output? I live in EU.
If you put it lower than it is you may end up broadcasting outside of legal limits. I’d just keep it accurate and use your calculated 5.8.
Hi Nik, I am in the U.K. and installing a 6dbi mcGill optimised antenna with 32 feet of lmr600. Should I input it at 5 because I know there is some loss with 32 feet of cable. I am now thinking the LMR600 was a bad investment due to new POC rules and I should have stuck to the RG58.
Do you know the DBI output of the EU Bobcat 300 miner?
Hi Nik,
I have been doing some research and I don’t think the 16.5DBM for the EU is correct. Everything I have read it’s coming back at 20DBM? Can you confirm, maybe it’s recently changed in 2022.
If I google what is the eirp limit Europe, I get a global list, even if I search for U.K. all comes back at 20DBM can you confirm your findings.
Thanks
Ben
hi man.
how could I know what the best (RX/ TX DBI) is according to my installation.. any calculations or advise
antenna 10dbi . lmr400 30 meter
antenna 10 dbi. lmr400 5meters
antenna 8,5 dbi. lmr400 20 meters.
and specific calculation can assume what should I adjust my flarm booster,,,>>>???
thank you