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PtP vs. PtMP and max EIRP |
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Written by LLigetfa
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Sunday, 10 September 2006 |
" We were getting a little off topic in the thread »15 Miles shot. How to do it? so I thought I would start a new one.
In that thread, the deciding point whether the 36dB EIRP limit applied was the number of clients... more than one being PtMP. I initially thought it was based on the principle that highly directional antennas were allowed the higher EIRP based on the fact they are not spewing RF in all directions and not solely on the number of clients.
I've been reading through some of the IC regs, trying to get clarity but am not entirely clear on it. I thought I read somewhere that there are systems that deploy some sort of sequencing of AP arrays (directed beam) and somehow managed to convince FCC to allow PtP EIRP in both directions."
IntraLink:
Yeah, I've seen justification for PtP EIRP on PtMP antenna arrays.
IMO that is not allowed.
The PtP regulations in Part-15 were designed so that narrow beamwidth systems could have more power. Because they are narrow their effect is less on the area.
True, you can multiples of these systems and spread them out over degrees, but they should still be dedicated PtP.
The beam steering antennas think that every client they talk to is PtP and use the higer EIRP. Some may even be certified this way. But their use should still be PtP and I think users are instead creating a large PtMP array out of these by adding more clients per array element within the antenna.
This goes against the reasoning in Part-15 IMO.
You do this in the upper 5Ghz band and you could push a LOT of power on a "smart" sector. Which would be way above the 36dB EIRP level for traditional PtMP sectors.
cmaenginsb:
You're thinking of Vivato who used a phased array antenna. I can't speak for IC but the FCC certified this under the idea that each signal was "steered" towards the client so that the actual signal was a narrow beamwidth signal.
The original rules were quite blank and applied to both ends of a PTMP link, the FCC has since changed the rules about the client end and is looking more at the type of antenna used rather than the intent of it's usage.
Original thread location |
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