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RI mesh meeting 12/10

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W9GYR
W9GYR's picture
RI mesh meeting 12/10

We're holding a RI area mesh meeting on Saturday December 10th at 10:30 am. The location is Ladd Observatory at Brown University at 210 Doyle Ave. Providence RI 02906.

I'll be listening in on the KA1RCI repeater network before the meeting if you need directions. 145.350 / 144.750 with PL 67.0

We'll be meeting about once a month. The next one will be in mid January and we'll post the details here in about a week.

-mikeu

K1NPT
K1NPT's picture
Dec meeting

I wish I could attend but usually need a couple weeks lead time to synch up with the family's schedule.  I have nodes running as N1ASA at All Saints STEAM Academy and K1NPT at the home QTH.   Rogers HS in Newport has a new ham club W1VRC and is interested in a node in the south end of the city which appears to be LOS to K1NPT.   Also have an offer to site a node atop KVH HQ in Middletown that is LOS to N1ASA.  BTW, there is strong City of Newport + private investor interest in "resiliency" and "microgrids."  It may be worth thinking about and documenting  how a southern New England mesh could support local govts, schools, neighborhoods, and commercial interests recovering from a Cat 3 hurricane or other catastrophic event.  73, Mike

W9GYR
W9GYR's picture
future meetings and current PVD status

The December meeting was scheduled in a rush. I wanted to pick a date before the Brown radio club K1AD students are busy with exams. We'll pick a date for Jan. and post it here this weekend to give plenty of time for people to plan. We might also hold a repeater net between the monthly meetings.

I've seen those nodes through the vpn tunnels. It is good to make contact and we're looking forward to seeing more groups join. We'll be talking about collaboration with the Providence Emergency Management Agency this week.

Currently I have W9GYR on a mill building in Olneyville and Denis has KD1HA on a hi-rise on Atwells near downtown. We're very close to getting a 2.1 km link up across the west side of Providence. The map shows potential coverage for my antenna based on terrain. It is overly optimistic.

-mikeu

W9GYR coverage

K5DLQ
K5DLQ's picture
Hi Mike,
Hi Mike,
Good stuff!

questions:
Looks like you are using an omni antenna, correct? 
Are you planning to use the 2.4GHz band?
Which channels and bandwidth settings?

if 2.4Ghz...
I can attest that, channel -2 at 5Mhz works very well.  We have Bullet M2 + omni's covering 15-20 miles on -2 @ 5Mhz
A Rocket M2 + MIMO omni antenna would have better performance due to the MIMO (dual-polarity).
A Rocket M2 + MIMO sector antenna would have even better performance due to the 120 degree focused signal.

It's all about getting a clear fresnel zone (and that usually means height)

My $0.02 worth...

 
W9GYR
W9GYR's picture
config

I'm changing the setup for the w9gyr nodes every couple of days to try different antennas, configurations, etc. The green coverage plot does assume an omni which is what I was using before the kd1ha node was installed. I posted the coverage map in case anyone in the green area who might see it wants to try a connection to me. I can setup a second directional for a test. It is a somewhat reasonable map of how far a directional at my site can reach. But, I'm not currently operating an omni.

As of today the kd1ha node is a Bullet M2 with an 8 dBi omni and w9gyr is a Bullet M2 but with a 14 dBi flat panel. Reception at my end is about -80 with a noise floor at -95 on channel 1 with 20 MHz bandwidth. We almost got a link but it wasn't stable enough to form a connection. My w9gyr could receive fairly reliably at 90% LQ but kd1ha is in a much noisier environment in the middle of a bunch of skyscrapers downtown. My signal is probably getting swamped by the noise from hundreds of nearby wifi hotspots. Essentially we have a unidirectional link at the moment.

We're going to switch to channel -2 narrow as soon as Providence EMA can climb on the roof to change it. This photo shows a binoculars view of the building I'm trying to hit. It is the block shaped one just in front of, and below, the tall 1920s building that has the pointy top. Maybe not the best Fresnel zone, but I think we can get it to work. There's a good chance we can get a node on the hi-rise at far right which is about half way between the two existing nodes.



Here's a map of the west side of Providence nodes that we're working on or planning. PEMA is online but can't connect to kd1ha either. The hi-rise at the right edge of the photo above is labeled Tobey St. The Providence Radio Association W1OP has a tower on a tall hill near me. They are interested in joining the RI mesh but that may not happen until after the holidays. The rest of our RI nodes are using vpn tunnels. Once we get a wireless link up I'll write up all the details on my blog. Feel free to ping me if you'd like more info before I get around to that. I'm very interested in comparing notes. -mikeu

Providence west side mesh
 

K6AH
K6AH's picture
Use channel -2
Messing around with any channel other than -2 is a waste of time.  If you going up to change the channel, then I second Darryl's recommendation: channel -2, 5 MHz bandwidth.  If you need more bandwidth, then move to 5GHz or 3GHz where there's plenty of room in the ham band for 10 and 20 MHz width.

Andre, K6AH
 
KD2EVR
KD2EVR's picture
Just curious why you need to
Just curious why you need to go up to the roof - can't you connect via mesh to change the channel settings?
W9GYR
W9GYR's picture
QRM
Even from a mobile station close to the building we were not able to connect due to interference on channel 1. We tried several times from different locations but the rooftop node couldn't establish a stable link. We get LQ near 90% but NLQ never gets above 0%

-mikeu
K5DLQ
K5DLQ's picture
make sure that you reset your

make sure that you reset your DISTANCE value on the setup screen to an appropriate distance too.... it may help trying to connect to it from nearby.

W9GYR
W9GYR's picture
distance
We're currently using 4 km for the nodes at my site. The actual distance between them is 2.16 km. I'm not sure what the remote node is set for as I did not configure it. From what I understand a value too low will cause problems with a retransmission colliding with an ack. What happens if the value is set too high? Will that prevent a stable link from forming over short distances? My plan was to set it a little bit high and then after we get a working link increment it downward. Will a high setting make it difficult to connect over very short distances of about 1/2 km?

-mikeu
K5DLQ
K5DLQ's picture
it *could*. 
it *could*. 
I generally recommend setting it to the actual distance + 10%
KG6JEI
It is generally safe to set
It is generally safe to set the distance too far.

The worst impact is that the link may have slower throughput because the timers wait much longer because the max distance impacts the time nodes need to wait.

Ultimately they should still connect at the same RF rates because those are not impacted by the distance parameter it's just that the realizes throughput will be lower.

So for peak performance yes you want the distance to be roughly accurate, but if it's way out there it's fine the link will still remain stable.
K6AH
K6AH's picture
power may be set too high
This 100% LQ / 0% NLQ is fairly common. There may be reason to suspect the nodes transmitter is distorting. It would be interesting to see what lowering the power by 2-3 dB does to this. If you have the opportunity, I'd appreciate a report on your results. Thanks, Andre, K6AH
W9GYR
W9GYR's picture
The node was tested on the
The node was tested on the ground and worked fine until we installed it on the roof. Right now it is on channel 1 and we suspect that all the wifi hotspots in adjacent tall buildings are swamping the signals from a distance. We can't even get a link from 400 meters away. We're going to have it switched to -2 in a couple of days. I'll write up the details once we get it working including some of the things that we tried that failed.
W9GYR
W9GYR's picture
link up!
I tried lowering the power settings under the original configuration and did not see any improvement.

We then switched all the nodes to channel -2 @5Mhz. I was having difficulty with the flat panel but after I swapped it for an 8 dBi omni I was able to get a link yesterday afternoon. The SNR isn't great but the link is stable enough to manage the remote side. The speed is in the range of 0.2 - 2, though I've seen it go a bit higher. Now that I can read the signal strength that the remote node is hearing it will be a lot easier to tweak my antenna orientation to maximize it.

There's a chance we might be able to situate a node about half way between these two. We'll also be talking to the Providence Radio Association W1OP which has a hilltop site in Johnston only about 2.5 km away from me.

-mikeu
kb1jfg
kb1jfg's picture
reply to #1
See ya tommorow Mike!
 

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