5GHz EU Vs US and max output power for NBE-5M


  • D
    Custom Avatar

    I recently purchased a couple of NBE-M5 16 for private use, to set-up a point-to-point bridge 700meters apart.

    The line of sight is not very good, and some trees in between. My country is Sweden. And using latest FW revision for NBE-M5.

    During configuration of the AP & Station, I realized the following.

    • If the county is set to Sweden. Max allowed output power is apparently capped at 7 dBm, unfortunately, this is not sufficient to establish the link in my case (perhaps due to trees and NLOS).
    • At higher output power i.e. 24 dBm it barely set-ups the link and data rates fluctuates between 3-6MBps, which is better than nothing. However, in order to get 24 dBm option in NBE configuration, I have selected the Country profile as U.S., which apparently brings other legal issues relating to 5 GHz band in the US vs EU.

    Questions:

    1. Does anyone know if using the 5735-5850 MHz is legal in EU? I looked up some EU documents but couldn’t find any conclusive statement about whether it's forbidden (for private use)?
    2. For EU apparently in H-band, i.e. 5 470 to 5 725MHz 1 watt ( 30 dBm) output power is allowed. Question is, does anyone know which EU country profile makes this option available for NBE?
    3. I can see there is DFS option available in NBE Configuration, might not necessarily mean it is working as other pointed out in other Ubiquiti topics. But from a legal perspective is it good enough if this feature is activated/checked ( to go for the max possible output power, in the case of NBE is 26 dBm)?
    4. Is TPC (Transmit Power Control) option available in NBE-15 ?

    As per my understanding, Sweden allows 1watt ( 30 dBm) with DFS+TPC as in other EU countries, but it’s disappointing to find out that NBE doesn’t allow anything more than 7dBm, at least as default for country profile Sweden.

    Please kindly help on how to get to 24-26 dBm legally in EU :-)

    I Sincerely thank all respondents in advance.

    PS: I am a novice, just starting to learn many things same time in regards to these wireless bridges. So, please

    kindly bear with my stupid questions :-)


  • D
    Beta Testers

    You seem to use subband frequencies reserved for indoor use, they are limited to 23dbm power. So if you add antenna gain 16 dBi to 7dbm output power you will get these 23dBm. You will have to use the upper DFS frequencies to get 24-26 dBm legally.

    Please notice that these products are for LOS only, they barely work in NLOS !


  • D
    Super Users

    dbabuy wrote:

    As per my understanding, Sweden allows 1watt ( 30 dBm) with DFS+TPC as in other EU countries, but it’s disappointing to find out that NBE doesn’t allow anything more than 7dBm, at least as default for country profile Sweden.

    Please kindly help on how to get to 24-26 dBm legally in EU :-)


    To expand upon this (and what  has already said,

    Regulations are based on "EIRP" (Effective Isotropic Radiated Power"), which is comprised of several components:

    • Conducted power (i.e. transmit power of the radio, set in its interface – in your case 7 dBm)
    • Antenna gain (in your case, 16 dBi)
    • Cable losses (in your case, 0)

    so, 7 + 16 + 0 = 23; putting you right at the limit of your selected channel.

    If Sweden is anything like the US, you probably need to select a different channel (e.g. in the UNII-3 band -- up around 5800 MHz / channel 149) in order to have the higher power limit.

    Running with the US settings, you're pushing 26 + 16 = 42 dBm EIRP (or roughly 100x more power* than you're legally allowed).

    • dBm is a logarithmic scale.  If you increase by 3 dB, you double the power (in mW).  If you increase by 10 dB, you increase the power (in mW) 10x as well.

  • Beta Testers

    In addition to what already told, you have only channels for outdoor use with high TX power here in europe… AND 5725 - 5850 is NOT allowed/unlicensed/free.
    Your problem is LOS @ 5GHz band with 700m distance.


  • D
    Custom Avatar

    Thank you , @dpurgert, @Skipper0815 for a kind responses!

    ,

    I have included a screen shot of my M5 AP’s GUI.

    • Do you mean that “TX Power” in the GUI isn’t the E.I.R.P what regulations refer to? In my case, as you explained EIRP  = Tx power+Antenna ( 24+16) = 40 dBm, just wanted to double confirm.Due to the fact that it has an Internal antenna of know gain, thought Ubiquiti might be displaying dBm value referring to EIRP ( Known Gain factor taken into account)?

    • Apparently, I cannot have a bridge solution here with the poor LOS in my situation? 900MHz not allowed in EU ( license band)? and with 16 dBi antenna results In front, guess you would doubt a 23dBi LBE-M5 would be any better? I am just happy to get around 2-5 Mbps not overly ambitious after seeing the initial results.

    • Btw, In general, I am a bit confused regarding the reasoning behind why a higher gain antenna ( more complex to a simple isotropic antenna)  would be penalized by regulation for compensating with a lower allowed  power feed to the antenna,  isn’t the whole purpose of having gain in the antenna to increase reach without just putting more power into the antenna ? Let’s say, if a isotropic antenna with no gain is allowed to radiate 1W (30dBm), a gain antenna is allowed to only 1W/30dBm –minus Gain in dB . As far as the Signal can travel, signal from a isotropic, 16dBi, 23 dBi, all have pretty much same reach because radiated power has been turned down as gain increases ?

    I hope you are kind enough to answer my questions, I am novice trying to understand all these 1st time. So, perhaps some stupid assumptions/questions :-)

    Thank you,

    UBNT TX power4.jpg


  • D
    Custom Avatar

    Just noticed that the Picture is too small.  I retry…

    UBNT TX power5.jpg


  • Beta Testers

    TX power in WebGUI is just what's going to antenna from chipset. TX Power + Antenna Gain together adds to EIRP. Equivalent Isotropic Radiated Power… which means emission from antenna.

    I'm not sure whether a high gain radio will solve your problems in 5GHz band.
    has maybe more experience with that.


  • Beta Testers

    btw: Try 10MHz channel width… that's more likely to work than 40.


  • D
    Beta Testers

    dbabuy wrote:

    Let’s say, if a isotropic antenna with no gain is allowed to radiate 1W (30dBm), a gain antenna is allowed to only 1W/30dBm –minus Gain in dB . As far as the Signal can travel, signal from a isotropic, 16dBi, 23 dBi, all have pretty much same reach because radiated power has been turned down as gain increases ?


    Yes that's sad but true, regulation limits the effective radiated power. The only reason to use high gain antennas is they are more directional and will pick up less noise, thus maybe reach farther without using more transmit power.


  • D
    Super Users

    dbabuy wrote:

    Thank you @dadaniel@dpurgert, @Skipper0815 for a kind responses!

    @dpurgert,

    I have included a screen shot of my M5 AP’s GUI.

    Do you mean that “TX Power” in the GUI isn’t the E.I.R.P what regulations refer to? In my case, as you explained EIRP  = Tx power+Antenna ( 24+16) = 40 dBm, just wanted to double confirm.Due to the fact that it has an Internal antenna of know gain, thought Ubiquiti might be displaying dBm value referring to EIRP ( Known Gain factor taken into account)?


    Right, the "Tx power" is simply how loud the radio's internal chipset is; before accounting for any losses in cabling, and gains in the antenna.  The radios are (IIRC) split roughly 50/50 between modular (i.e. you can use different anteanna setups) and fixed (just one antenna); and it's a better design decision to keep the UI the same across all radios.


    dbabuy wrote:
    Apparently, I cannot have a bridge solution here with the poor LOS in my situation? 900MHz not allowed in EU ( license band)? and with 16 dBi antenna results In front, guess you would doubt a 23dBi LBE-M5 would be any better? I am just happy to get around 2-5 Mbps not overly ambitious after seeing the initial results.


    You're still limited to the EIRP your country's regulations impose. If you have bad signal now (with out-of-spec EIRP), it's not going to get any better with better antennas (and staying in-spec).  Best fix would be to get LOS.


    dbabuy wrote:
    Btw, In general, I am a bit confused regarding the reasoning behind why a higher gain antenna ( more complex to a simple isotropic antenna)  would be penalized by regulation for compensating with a lower allowed  power feed to the antenna,  isn’t the whole purpose of having gain in the antenna to increase reach without just putting more power into the antenna ? Let’s say, if a isotropic antenna with no gain is allowed to radiate 1W (30dBm), a gain antenna is allowed to only 1W/30dBm –minus Gain in dB . As far as the Signal can travel, signal from a isotropic, 16dBi, 23 dBi, all have pretty much same reach because radiated power has been turned down as gain increases ?


    In general terms, it's because you're using unlicensed spectrum (that is, anyone and everyone is allowed to use it without applying for any licenses), so there have to be limits imposed somewhere, so it's not an "arms race" between you and your neighbor for who actually has usable signal.

    The thing you're forgetting is that the antenna adds in both directions.  For example, if you have a setup with +0 dBi antennas and 30 dBm EIRP, you will get about 300 meters before hitting -60 dBm (the "ideal range" is generally considered to be -50 to -60 dBm.  Above -50 or below -60, the ap tends to lose ability to understand the modulation from the other side – but every situation is different, and some radios tend to do better with Rx in the -40s).

    Now, we add in +16 dBi antennas.  The EIRP is still limited to 30 dBm, but you can get about 1800 meters and still be above -60 dBm on the Rx side.

    +23 dBi antennas will be a bit above 3600 meters.

    NB -- all figures above are simply calculating losses "over the air", and do not account for external interference / other people using the frequency / improper alignment / solar flares / local weather phenomena / alien invasion / phase of the moon / you feeding Gizmo after midnight.


  • D
    Custom Avatar

    Thanks , , ,

    Does this is also mean, If I install a 29dBi antenna ( PBE-M5-620 ), and the EIRP limit is 24dBm.
    Then the Tx Power setting in the GUI will literally be minus 5dBm ?
    EIRP ( 24 dBm) = 29dBi+   -5 dBm ?

    Or is the regulation different in situations where  gain of antenna is comparatively high with regards to EIRP ?


  • D
    Beta Testers

    As tx power can't be negative, you're not allowed to attach this antenna then.


  • D
    Custom Avatar

    Sorry for incorrect wording. PBE-M5-620 AP comes with an inbuilt antenna of 29dBi.

    So, from your reply, in other words, it means PBE-M5-620 will not allow frequency selection of frequencies which have allowed EIRP value less than the antenna gain itself, as power cannot be in negative dBi. right?


  • D
    Beta Testers

    It should only allow you 1dBm tx power on DFS outdoor bands then.
    If you take it accurate it is in fact illegal to use it in europe because regulation says ATPC is required for 30dBm power, and Ubiquiti does not support it. They however support it in AC products AFAIK.


  • D
    Super Users

    dbabuy wrote:

    Thanks @dadaniel, @dpurgert, @Skipper0815,

    Does this is also mean, If I install a 29dBi antenna ( PBE-M5-620 ), and the EIRP limit is 24dBm.
    Then the Tx Power setting in the GUI will literally be minus 5dBm ?
    EIRP ( 24 dBm) = 29dBi+   -5 dBm ?

    Or is the regulation different in situations where  gain of antenna is comparatively high with regards to EIRP ?


    yes, but the powerbeams only go to -4.

    , yes, you can set negative Tx power ;)


  • D
    Beta Testers

    Please tell me how much mW power is -4dBm ….


  • L

  • D
    Super Users

    dadaniel wrote:
    Please tell me how much mW power is -4dBm ….


    Without looking at Google, etc. a bit less than half a mW (0.0005 W).

    According to that calculator  linked, 0.4 mW (0.0004 W).


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