[OpenRelief Developer] Ham Radio Operators

[Andrew Back]

Hi Al,
On 3 May 2012 04:04, al Hart <kandalgil at hotmail.com> wrote:
>
>
> Not sure about the UK or Japan but in Oz we can actualy look at what
> frequencies are available and apply for those if interested as well .
>
> http://web.acma.gov.au/pls/radcom/register_search.main_page

Nice! Not sure what the situation here is... Well, you can apply for
non-operational test licences for things such as GSM spectrum — purely
for testing. But not sure about anything else outside of standard band
plans.
> I suppose what I would like to know from this end would be things like
>
> What range are you currently getting
>
> What range would you like
>
> What band eg MF, HF,  VHF,  UHF etc

We're looking at using unlicensed spectrum on 868MHz and 433MHz, as
used by wireless weather stations etc, for low data rate comms between
ground-based sensors and drones overhead. So this is for sensing
things such as water ingress, weather conditions, earthquake and so
on. I believe that you typically get 100m or so range in the open with
modules such as the HopeRF RFM12B, but we'd like to get nearer
500m-1km and to have a solution that would work better under adverse
conditions where there might be trees/buildings in the radio path etc.
I'm not sure how we could really use amateur spectrum for the sensor
comms, as my understanding is that a solution is required that can be
deployed by anyone, and to have something that is dependant upon
licensed operators and/or can only carry traffic to/from licensed
individuals would be less than ideal. Also, since this needs to work
anywhere in the world and to be capable of being deployed in short
order, we can't use any spectrum which would require some sort of
application to be made which would not be turned around extremely
quickly.
So, the only solution I can see at this point is to use unlicensed
spectrum for sensor comms. But where the amateur radio community could
help here is in RF engineering etc, working within the constraints
that we have. And one promising technology that we might look to for
increasing the range is DASH7:
http://en.wikipedia.org/wiki/DASH7
> Do you want to be able to use repeaters

We have been thinking about ad-hoc/mesh networks using something like
IEEE802.15.4, but some thought would need to be given to architecture.
So for now we're looking at a much simpler protocol with the HopeRF
module and with the idea that drones will do a fly-by over sensors and
at which point data will be uploaded.
Another possible area that radio amateurs could help with the
infrastructure might be in providing long distance radio "trunks".
I.e. operating HF/VHF and/or satellite links that get data in/out of a
disaster stricken country where national comms networks might all be
down. Pretty much the rest of the OpenRelief comms system could be
unlicensed and operated by anyone, and just one licensed operator
would be required in-country in order to provide backhaul for
aggregated data.
> Power of transmitter not to be confused with the power emitting from the
> antenna can be different

Yep, TX output != EIRP. I would imagine that the power constraints
associated with unlicensed spectrum are for effective radiated and not
power at TX.
Cheers,
Andrew
-- 
Andrew Back
http://carrierdetect.com