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Microwave linking


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I'm not sure it was ever specifically mentioned in the GMRS rules, either allowed or not allowed. 6GHz microwave is used for all kinds of stuff. 


I don't see why a person could not use it to link a couple of stations, but I think it centers on channels, and the finite number of them. Is it necessary, and does it limit others ability to share the channels (if you have a 650 tied to a 700 in two adjacent locations, maybe 10 miles apart or even the same channel and further apart used just for creating more "coverage" for a unified system). Probably just comes back to common sense. Lots of dreamy projects out there, but practical and necessary is another story. 6 GHz microwave hop and the license will cost a few bucks.  

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To link multiple systems, you need a full duplex link repeater. You could do a point-to-point from one repeater to another on a simplex system but to add more than that you'd need a full duplex system. 


Their are two ways to easily perform multi-system links. Build a LAN network with 802.11 protocols using something similar to these…







Or you could add an extra "link" radio to you're repeater that has the input/output of another repeater (this is easy to duplicate to link multiple repeaters together requiring a regular repeater for a hub and a link radio with the next closest repeater pairs on all the other repeaters you wish to link in). 


That is the only way I know to do a multiple link system wirelessly (there's always the running wire method).

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  • 5 months later...

Anyone have a good way to link 2 Quantars together for GMRS use?


I don't really know if they are true "line of site", but with a spotting scope at location #1, (Building Mounted on roof of commercial building on a mountaintop)


I CAN see Repeater Location #2 (500+' tower w/ our gear at 420') --  approximately 26 miles as the crow flies...


I've done a few Cisco Aironet point-to-point 2.4ghz installations in the past (5-6 yrs ago) that spanned 6 miles or so at 2mbps.

(only needed 512kbps anyway)  But have no further experience w/ wireless anything...   


I do have wireline controllers w/ v.24 daughtercards installed in the Quantars.  Was initially thinking of ROIP using UDS or similar 4-wire type modems,

(the wireline cards were intended for use w/ microwave link / 4-wire leased line / etc.. and the Batboard gurus have been working on a linking project for some time now)

but don't think I can get internet access at location #2.   (I can get FIOS at #1 and can also get a frac or full T1 via copper)


(supposedly the Quantars only need 64kbps of bandwidth -- though have heard the 128k figure floated about)

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I was actually talking with a /\/\ tech earlier today about linking Quantars. Me and some friends have been wanting to get a VHF pair in Lubbock county and a VHF pair in either Williamson, Travis or Hays county (roughly 370 miles apart) just to run P25 with encryption. 


Anyway, what was learned from today, the Quantar really pre-dates ROIP so it was mainly shipped with an option for 4-wire leased line connection. That being said, there is currently Raytheon's NXU which takes 4-wire to VIOP (at $900 a pop) and a handful of others for around the $500-1000 range (not sure I would trust the $150-$200 Chinese options to be maintenance/headache free).


That's about all I've found out specifically about Quantars…


If you can see it, it's LOS. 


Oddly enough, I'm in the WISP business. Most of the stuff I deal with is Ubiquiti 5 GHz and 3.5 GHz APs. Usually run about 4-8 miles at the most but that being said an acquaintance just tested a hop using high gain dishes that runs from Denton, TX to Saginaw, TX (it's about 35 miles) and it's seeing 120 MB/s up and down. I'd run the path loss on it. So for a 2.4 GHz 26 mile hop, your looking at about 72 dB of loss…which should mean full speed as long as there isn't too much noise.

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