David Lush writes:
> Here's a presentation made by UNDP's Daniel Stern on the use of HF radio
The Stern article recommends a particular network topology with HF
for long-distance links to a hub, then VHF for short-distance local
links within an area. The article is presented from the perspective of
a single large organization (the WFP) with high-level public funding
operating its own infrastructure.
The Stern article opens by suggesting that a change in topology to
accomodate additional sites in a local area with cheaper technology
somehow makes the whole thing "cheaper, faster, more flexible and
less resource-intensive." I'd prefer to characterize the newer WFP
configuration as taking appropriate advantage of economies of scale
in a very large organization.
Adding all those new stations in a wireless LAN with a local hub
rather than through a direct link to a distant central hub adds
complexity and cost at the local hub, but lowers the marginal cost of
a new site in the wireless LAN. It does not obviate the necessary
initial not cheap, not fast, not flexible, and not less resource-
intensive investment in the long-distance HF link between the local
hub and the central hub.
Interestingly, this "new" configuration by the WFP has been
recommended by Mission Aviation Fellowship (MAF) for quite some
or more particularly
Are we to infer from the lack of acknowledgement of the work of
MAF that the WFP was not at all inspired or influenced by MAF?
The Stern article strikes me as irrelevant in instances where scale
economies are not feasible due to lack of scale, as in the case of
one organization, isolated in a very remote area, with no expertise in
radio or other technologies. The private networks of large
organizations like the WFP, embassies, aid agencies, etc. are not
generally available to ordinary consumers. The issue then more
directly becomes one of how to build scale, how to build the
The solution may require suppliers of HF radio services to adapt
their technologies to make them more affordable to more
consumers. Competition may also help in spurring this adaptation.
This is the issue we presently face in Uganda.
While large private networks are not accessible to isolated
organizations not engaged in hunger relief in Uganda, there are the
commercial HF email hub providers in Kampala mentioned in
passing in the Stern article. These all apparently charge a fee per
kilobyte, resulting in high charges to consumers who upload and
download large files indiscriminately. A colleague writes to remind
me that not all the private-sector operators of HF radio email hub
services meter by the kilobyte. We've known about a service in
Benin for some time. I'm told that a service in Dar also charges a
flat rate. These may be avenues to explore to reduce costs to the
consumer in a growingly competitive market.
Long-time readers here may recall an earlier discussion about this
issue. If memory serves me correctly, one concern raised about
flat-rate services had to do with network congestion, given the
inherently low bandwidth of HF links. Kilobyte charges encourage
users to economize on that bandwidth. Issues to be investigated
with the flat-rate service providers...
Jeff @ Washington