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Sanity check on 41km PTP link

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KG7LMI's picture
Sanity check on 41km PTP link
Hi, New to the forum and we are planning our first connection. Hoping someone with actual experience can tell us if our basic strategy makes sense. We are going to set up a PTP link from mountaintop to mountain top, on repeater towers that are ~ 100ft high. The distance is 41km but there are no obstructions, not even trees, even within the 1st Fresnel zone. Equipment will be a NSM5 at each end. We've used the Airlink calculator to validate the path, and it says we'll have ~ -79 dBm signal with the NSM5 at full output and assuming the full 16 dBi antenna gain, with 25.35 Mbps throughput. The signal strength is well within the sensitivity of the NSM5, so assuming this is all correct we should be able to establish the link (our goal, btw the way is to achieve a min 10 Mbps throughput). Can we trust this result? We're going to dry run the setup on the ground, but it is a lot of work to get to the sites and climb the towers, so we're looking to have as much confidence in the deployment as possible before attempting this. I looked for forum postings that described the typical distances that are possible but was not able to locate anything relevant. Any feedback or links to relevant articles is appreciated. Thanks! 73, Rob KG7LMI
Yavapai County AZ Emergency Coordinator
K6AH's picture
That should work
Stay above 5890 MHz and this should work fine.  You might consider a device with a narrower beamwidth (NanoBeam M5-19 for example, available in our current 3.17 release candidate) to avoid it inadvertently becoming a PtMP device.

Andre, K6AH
AE6XE's picture
Ditto, I'd put up one of the
Ditto, I'd put up one of the P2P instead, same cost +/- in the ballpark, but yielding much higher data throughput.   

Model  xmit (dBm)  gain (dBi)  ERP (dBm)  ~BW (deg)
NS M5 27 16 43 42
NBE-M5-16 26 16 42 25
NBE-M5-19 26 19 45 10
NB-5G22 23 22 45 5
NB-5G25 23 25 48 5
PBE-M5-400* 26 25 51 5
PBE-M5-300*   26 22 48 5
*newly supported in AREDN3.17.1.0RC1      
KG7LMI's picture

We had planned to use the higher end of the 5 GHz band, so we're good there.  Will also look into the other products too. We purchased the NSM5s figuring it was a good way to get started and planned to use them for some of the shorter hops in a future phase. Appreciate the feedback. 

Joe, excellent table!


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