New site,
4600 lite with sector antenna, and 4625 client radio. 1.7 miles.
I have two sectors, with two clients. Why is there a 10DB differential between the AP and client signals. Both are TX’ing at 36 db EIRP… They should be the same… Something isn’t right with that math…
Have you ran the paths in LinkPlanner?
Could it be that one of the two SM is misaligned or connecting to the sector’s side-lobe?
Without more information and screen shots this is going to be difficult for us to help troubleshoot.
Two different sectors. one client on each sector. Both of them are showing a 10db difference in RX between the ap and sector. Like the AP(s) is deaf, or the CPE isn’t actually TX’ing it’s full 10DB to reach 36 EIRP… ie the client hears the ap at -65, the ap hears the client at -75. Both the APs and CPEs are showing full TX power at 36 EIRP…
Can you show a screen shot of the AP and SM’s status page?
The SM antenna has a lot more gain than the AP antenna, so the SM will get a stronger signal from the same 36dBM EIRP.
That isn’t my understanding of EIRP… If EIRP is the same on both. The RX signal on both should be the same…
No, EIRP is tx power plus gain. Think of it like this, if you have two SMs at the same spot connecting to the same AP but one has 15 dBi antenna while the other has 25 dBi, would you expect a 10 dBm higher signal on the higher gain SM? Same thing applies on the AP side.
IMO, the way to go with 6 Ghz APs is a bunch of tight pattern high gain antennas like 30° horns or similar. That, or a big beamforming array on the AP…
That would certainly explain the difference in 10dBm he’s experiencing.
EIRP aka Effective Isotropic Radiated Power, is just that… the radiated power from the emitter. It doesn’t take into account the receive characteristics (antenna gain, receive sensitivity, etc) at the receiving radio.
Guys, I know EIRP is TX power plus gain…
So, lets think this through. But, I am happy to be wrong here.
The AP has an antenna of 15 db, and a 20B TX power. Total 35
The CPE has an antenna of 25, with a TX power of 10. Total of 35.
Freespace loss between the two is the same, no matter what. In either direction…
So, how is RX signal different on both, when the EIRP gain is the same in both directions?
Are you both seeing a 10DB difference in your AP and client signals?? Or are they the same? And how do you account for that at the tower, when I client should be sending a perfectly fine signal to the AP, just like the AP is sending it to the cpe?
I modeled this through LP and while I wasn’t able to select a 15dBi antenna for the AP, I was able to find a 16.6dBi horn antenna to model with.
You’ll notice that there’s an 8dB delta between the AP’s and SM’s receive strength:
So this threw me off too when I first started working with 6GHz and this 36dBm EIRP on both sides… mainly because I was used to 5.8GHz rules that allow you to crank up the TX power on the SM side up to like 50dBm EIRP.
Got it… It didn’t “click” in my mind I guess… You wouldn’t figure in the TX power of the AP on the RX side. So, it’s going to be different.
Key factor to understand is the different the regulations.
In 5.8Ghz (North America), the AP to the SM follows the PMP regulations and has a max EIRP of 36dBm. The SM back to the AP however is treated as a PTP connection and therefore can have higher EIRP.
In 6ghz the EIRP is controlled by AFC and has max EIRP of 36dBm. Both the AP and SM could be limited by AFC. If you add a higher gain antenna, power will be reduced to whatever AFC allows.
Make sure to check the AFC area calculator first to find out what is allowed in your area before you start modeling.
