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AREDN RF Node Field Experiments
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Topic starter
06/09/2021 11:53 am
Good morning,
It was a great day to be out and about. Warm not hot with clear skies and light winds. My expectations were low as far as the capabilities of the hardware. I must say my expectations were exceeded. The first shot was very close to a 1/4 mile. After seeing the units link up we realized that John’s garage was within the line of sight. We then repositioned the unit and drove to the far end to check on signal strength and throughput. Both parameters were about the same after repositioning.
Next we setup for a longer shot. John estimated that the spot he picked out was 4-5 miles. His eyeballs are well calibrated. We stopped along Nitch Road and setup the TP-Link CPE 210. John had a good idea as to where the far end unit was positioned. He aimed the unit as I setup the power and connected the ethernet cables. The two units linked up immediately. Throughput was just under 6 MBS. At some point I realized that both units were set to transmit 18DBm. (63mw)
Next I changed the transmit power to MAX at both ends. (27DBm, 500 mw) Unexpectedly the throughput remained the unchanged. Later John used Google Maps to plot the distance between the two points and came up with 4.6 miles or 7.4 KM. TP-Link says the units are capable of reaching out 5+KM. These units operate at 2.4 GHZ. Power consumption runs about 125 milliamps. We used iPerf speed to estimate throughput.
As John says further testing needs to be done.
What I learned.
1) The units are simple to setup. Accurate aiming was not necessary. Pointing in the general direction was sufficient in all cases even when you could not establish line if sight with normal vision.
2) I am convinced that these units would have linked up over considerably longer distances. At some point in the future I hope to get a better idea of just how far apart these units will function.
3) There was considerable variation in signal strength across the gap between transmitter and receiver. Real time receive levels fluctuated as indicated by the receivers signal to noise measuring tool. This was true for both the short and long shots. Connectivity was never lost during our testing. The screen shot below was taken during the 4.6 mile shot.
Topic starter
06/09/2021 11:54 am
Topic starter
06/09/2021 12:03 pm
Photo 1 is a view from Nitch Road looking towards the far end node. Photo 2 is of the apparatus used to power the TP-Link CPE 210 AREDN node
Topic starter
06/09/2021 12:10 pm
Illustration of TP-Link CPE210 RF propagation patterns
06/09/2021 2:46 pm
How high up we're the nodes placed with respect to the ground? I see tripods in the pics. We're the nodes at 5' or did y'all go higher?
Topic starter
06/09/2021 3:56 pm
4 - 4.5 feet
Topic starter
06/09/2021 4:17 pm
Setup a TP-Link CPE 210 on a mast at the front of my house. It’s 12-13 feet off the ground and aimed it towards the CNM. Entered the park from the east entrance and pulled over at a spot with a little room. The spot is before the tunnel and before the Serpents Trail pullout. I set up the other unit on a 6’ 1 inch schedule 80 PVC pipe and aimed it in the general direction.Powered the thing up and much to my surprise I saw the other unit and the mesh. Played with the azimuth but could not improve the signal strength. The signal was so weak that I could not activate any services on the mesh and at times the mesh disappeared from view but I never lost connectivity with the far end node. I believe I was a the extreme limit for these units.
Later I realized that the unit on my house was transmitting full power (500mw) but the unit I had with me was set to transmit at 63 mw. Decided to come back to house and eat some lunch and recheck the aim point. Will reset the other unit to full power and go back to the CNM and give it another go.
My goal is to setup an AREDN shot at the same spot KE0OHF uses for the 10 meter net and have it up and running for the Thursday evening net.
06/09/2021 7:53 pm
I think I'm just a mile or so due east of your QTH, so once I get an external antenna, I should be in a direct line from the CNM if you're aiming at your house.
Topic starter
06/09/2021 8:43 pm
Setup a second AREDN link today, one node at my house the other located in CNM 1.5 miles past the entry point. Signal was much stronger and I was able to access Mesh-Chat and leave some notes. I shimmed the radio at my house to increase the elevation a few degrees. Throughput varied from a high of 774 Kbits/sec to a low of 271 Kbits/sec. One other reading was 465 Kbits/sec. Although these readings seem low they are good enough for basic services like MeshChat.
Tomorrow will attempt a link from Cold Shivers Point at the same spot where KE0OHF sets up for the 10 meter net. Did drive by the site today, it appears there might be some trees in the way.
Topic starter
06/09/2021 8:46 pm
@n0wkr Chip I agree, you may have to make the shot through some trees. Based on what I’ve seen so far these units are very robust when it comes to pulling a signal out of the noise
Topic starter
06/09/2021 9:15 pm
Been playing with Google Earth, I found the spot where I setup in the CNM, distance is 8.16 miles from house
07/09/2021 7:55 am
I ordered a set of the 2.4GHz units to connect my house to the garage. From the garage I can see the top of the two roads in Gateway, Nitch Road and John Brown, it will give me a good relay point.
Next will be to order a set of 5GHz nodes to hit the cell tower at about 5 miles.
73. John, WJ0NF
John Fuller - WJ0NF
ARES - Region 9 District 4 - AEC - Technology
Topic starter
07/09/2021 4:47 pm
I ordered two Mikrotik LHG 5 units, expect them early next week
Topic starter
07/09/2021 4:57 pm
Setup an AREDN shot from my QTH to Cold Shivers Point in the CNM, visibility was so poor I could not see Mt. Garfield, it is my landmark reference for aiming. It didn't really matter because I pointed in the general direction and found a signal right away. Ran 3 iperf tests and all 3 indicated about 1 MBS. Will return Thursday evening and meet up with KE0OHF at Cold Shivers Point and establish a link to the mesh, don't know if the mesh will carry streaming video but will give it a go. First screen shot is results of 3 iperf tests
Topic starter
07/09/2021 5:13 pm
AREDN link established September 7, 2021 Cold Shivers Point to my QTH
Screen capture of S/N ratio being reported by far end node to the near end node. This reading is unusually high based on my limited experience. The receive signal at the near end was very steady.
Google Earth says it is 8.64 miles from my QTH to Cold Shivers Point. IMHO this distance it at the limit of the hardware.
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