[aprssig] The East will Rise again! (at 9600?)(bands?)

Brian D Heaton ky9k-lists at ky9k.org
Thu May 5 15:22:17 CDT 2016


On 5/5/2016 12:04, Robert Bruninga via aprssig wrote:
>> EOCs already have issues with desense from multiple radios on 2M or UHF
> Actually, I agree.  6 meters or 900 MHz would be ideal for the backbone.
> Rememebr, these sites are very remote and will NOT have any local unlicensed
> 900 MHz junk in the near vicinity.  So they might actually work in the
> Amateur allocation.  Any end points in propulated areas, however, will still
> be problematic.
>
> Is there any channel in our 902 MHz allocation that is NOT shared with all
> the unlicensed stuff?
Having the backbone and user access of separate frequencies/bands is 
important to good operation and throughput. Unfortunately, the whole 
900MHz band is shared with Part15/ISM.
> It all boils down to radios.  I suggested 2 meters only because we are all
> sitting on stacks of them.  But I don’t like using any modern synthesized
> radio at a remote site.  I prefer the old XTAL ones.
>
> And there is a huge supply of low band 100W mobile rigs at every Hamfest
> (or are the all gone by now)?  But the ones I have take too much pwer, and
> are too big to operate from small solar...

A Syntor/SyntorX for sites with commercial/generator power and something 
like Maxtracs/GM300s for sites on Solar. They are all widely available 
for 70cm, compatible with 9600, tend to be reliable, and many APRS digis 
are already using Maxtracs/GM300s on VHF. The old rockbound radios are 
getting quite long in the tooth. I suggest that reliability on good 
quality commercial synthesized radios approaches or exceeds that of much 
older rockbound radios.

Tom's suggestion is better than my own. IP-based links on 5.9/3.5GHz 
will likely provide much greater throughput on most links. They also 
have the advantage of offering transport of a lot more than just AX.25 
frames. If desired, run both 70cm and 5.9/3.5GHz parallel links or 
parallel 5.9 and 3.5GHz links. At those frequencies, antenna gain is 
relatively cheap and doesn't require any additional power budget.

How "small" solar do you want to go? It seems the any solar/battery 
configuration capable of running a couple 30-50W UHF radios will run a 
pair (or 3) IP radios with power budget to spare.

-Brian



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