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Mobile 900Mhz?

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K5DLQ
K5DLQ's picture
Mobile 900Mhz?

Has anyone tried a mobile 900Mhz node deployment?

kg9dw
kg9dw's picture
No, but....

None of the Ubiquiti devices that support a single external antenna currently work with that external antenna with the AREDN firmware. For example, you can't use the external antenna with a Nanobridge. So you'd have to use  a Rocket mobile!

Of course, as I type this, that could be a benefit. If you put a Rocket in your mobile with two antennas running in diversity mode, the multipath problems may be reduced. 

All this to say no, I haven't but that's an interesting idea. I'm planing on doing an install of our first M900 rocket up on a grain elevator today....it should be up at the 150' level.

kg9dw
kg9dw's picture
Read this post

http://www.aredn.org/content/900-mhz-results#comment-294

900MHz mobile is highly unlikely to work due to the huge Fresnel zone.

WK7G
AREDN Meshtastic pass through.
I would think an interoperability pass through to permit Meshtastic traffic into meshchat or meshmail would be a great way to work a mobile light weight connection. A raspberry pi with a Lora hat and a connection to an AREDN node could pass packets through a NodeRed script. You would have to discriminate the non licensed traffic and deal with only unencrypted packets. Leveraging both platforms seems to me to be a good thing!
K7EOK
My 2 cents
AREDN is not a cell service where you can roam ... the connection is made between two nodes and has to be evaluated by the firmware as being good enough to connect which takes time.  Mobile kits do work so long as you point at a known node, but it takes in my experience at least five minutes for a newly powered up node to establish a link and get onto the OLSR routing tables so traffic can be routed to the mobile node.  So ... if you stop and put an antenna up and aim it and wait ... sure.  Not remotely possible from a moving vehicle and omni antennas only work at short distances. 


Also, if someone wants something just for text messages rather than full blown AREDN and wants it to connect faster, look into Meshtastic.  It does work at close range (not well beyond a few miles) and is very forgiving of aiming.  In my experience the results from a moving car are questionable, but if you stop for a minute, and put the device in the air outside the window ... you can send and receive right away.  The reason why it works without delay is that it is there is no TCP/IP and no network routing tables ... it's spray and pray with all packets auto forwarded by all other nodes.  Not fully reliable, but fast and easy.

Edit

I should have put the second paragraph first and talked about trying to mix AREDN and Meshtastic.  I don't think this is a good idea at all, the Meshtastic firmware is a free for all and AREDN is having enough problems with it's changes as well.  Just operate two systems in parallel, that's what we are doing in some places here.  I won't run unencrypted Meshtastic and only use a private channel on a different frequency to stop being annoyed by all the "CB style" traffic, and encrypted traffic cannot go over AREDN, and the two are just not compatible in design or intended use.  My 3 cents.


Ed
WK7G
I understand the strengths
I understand the strengths and the weaknesses of Meshtastic. It just seems like another tool in the tool box. Meshtastic is a very limited text, telemetry and limited serial communications device. AREDN is a very robust mostly fixed and limited portable platform. If you can work Meshtastic traffic into a chat server for mobile ops without changing or taking anything away from AREDN, it would be a plus in emergency situations.
K7EOK
The moment you do that then
The moment you do that then someone will complain that the Meshtastic/AREDN connection won't support images, Winlink, etc.  I think they belong as separate systems so that one doesn't ruin the other.

Best,
Ed
WK7G
I don't see how it would ruin
I don't see how it would ruin either platform! If they are run separately but pass simple text messages through a tunnel or packet transfer.
K7EOK
Just for a moment, let's
Just for a moment, let's imagine the techical issues are solved.  Please tell me ...

What does Meshtastic bring to AREDN that cannot be done by AREDN alone?  What would this actually look like in use, who does what where with which equipment.

Then, what does AREDN bring to Meshtastic?  Same questions.

Just because something could/might be possible doesn't mean either system would be any better. 

Ed
kf6iiu
ADREN vs Meshtastic
Comparing ADREN vs Meshtastic is like comparing SSB to CW. Meshtastic is based on LoRa, which is a mode usually implemented by an integrated module. Are there even any devices on the AREDN hardware list that can run LoRa? 

The maxmim bandwidth of Meshtastic is 250 kbits. (LoRaWAN, a competing bu more popular protocol( can do 125. Some of these devices say they can support voice sommunication at these bandwidths in a mesh (I's like to see in that actually works.) The usual application is for IOT data.

The Meshtastic protocol doesn't use TCPIP as I understand it, although a lot of Meshtastic devices seem to also have Wifi interfaces with TCPIP so they can upload data to internet services.

If you're asking about whether 900MHz AREDN would work mobile, there's no reason to think it would work any better or worse than AREDN on any other band. I do operate AREDN "portable".


 
VE7TOP
Rather than looking at LoRa a
Rather than looking at LoRa a better option is 900 mhz HaLow 801.11ah which offers speeds of up to 30mb at 1km distances.   Longer distance out to 6km or even 16km have been shown to work although the speed does decrease with distance.  Using this gear from ALFA -   ALFA Network Tube-AH 802.11ah sub 1 GHz outdoor AP/CPE + Fast Ethernet & PoE  (https://www.alfa.com.tw/products/tube-ah?variant=39429371985992) we have successfully connected to AREDN devices (hAP lite) and accessing the mesh remotely.   We are now going to be testing various distance scenarios.
 
WK7G
That sounds very interesting.
That sounds very interesting. The combination of higher speeds and differing propagation sounds promising.
K7EOK
That ALFA device is priced at
That ALFA device is priced at $199 on Rokland.  It looks like it has power levels for unlicensed use, and I'd like to see a more powerful outdoor unit for licensed (ham) use so it has a larger range.  I can throw an AREDN signal between a half mile and one mile depending on terrain with a Ubiquity Omni.  Anything else out there?    Ed
WK7G
That looks alot like the
That looks alot like the Ubiquiti Bullet AC
 

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