Not knowing your particular situation, I offer this experience for your consideration. We are using a 70cm audio link between two repeaters about 20 miles apart with about a 200m obstruction about half way in between. The obstruction is a saddle between the mountains that has a well defined ridge... pseudo knife edge? Turns out this is an optimum condition for 70cm with an obstruction, and works quite well. I found an article on the web written by a couple solders who developed the rules of thumb for this configuration in the field to get connectivity between sites in the mountains. I can send it out... not sure if the list can handle an enclosure, and don’t want to stuff it in every ones’ email box if they are not interested.

Thanks,

Bob

kk6ecm

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From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org] On Behalf Of Bob - AF6D
Sent: Friday, February 07, 2014 12:02 AM
To: app_rpt-users@ohnosec.org
Subject: [App_rpt-users] Parallel 900MHz Links

We are finally at the last phase of our build-out with three repeater locations with minimal overlap. We want to vote and simulcast on 2 meters. I asked how I could get IRLP and EchoLink connected, as well as a weather receiver and it was suggested that I get an unvoted URI for a controller (like the RC-210’s that we have) and use them to bring in outside sources. That was a great idea! But then it dawned on us that if in the event of a major earthquake or tornado or whatever the Internet would go down – and those sources too.

This became even more of an important matter because we want to run a parallel 900MHz link system. We can’t use the RC-210 approach because if the internet goes down so would our link. The repeaters are too far apart for building our own Ubiquity VLAN – I think. I don’t know the maximum power available at 900MHz and we don’t have LOS between the sites.

What are some ideas on getting a parallel link system in case we lose Allstar?

Thank you for helping me learn.

Bob