I have some ideas for services to remote areas that could be delivered
by a small satellite communications terminal if cheap enough.

What is the 'state of the art' for mobile satellite communications
links in terms of size of terminal and antenna, bandwidth up and down,
power consumption, and cost?  What frequency bands do they work in?

What technology trends are there and what might be the state of the
art in 5 years time?

You can learn a lot about satellite communication by studying current
deployments (i.e. Satellite TV (DBS), Satellite Radio and Satellite
Telephones).

As with all electronics, the cost of the systems are dropping.  The
components are getting smaller.  DBS systems use a small dish and the
rest of the electronics reside in a small set top box.

As for bandwidth, there is a rough correlation between size of the
receiving antenna and bandwidth.  Satellite radio is low bandwidth,
therefore a small (non-directional even) antenna.  DBS TV can have
bandwidth of around 40 Mbits/sec (for High Def TV), but the antenna is
larger.

I'm sorry that I don't know a thing about two-way satellite comms.

Within the consumer market there are already a few contractors that
have solved this problem and are offering full services to remote and
mobile locations.  The current leader in technology is Directway
Satellite (http://www.directway.com).  If you are interested in a more
mobile DirecWay solution, Ground Control
(http://www.groundcontrol.com/) is able to fulfill your needs.

   The state of the art in satellite communications is the Directway
DW7700 (http://www.groundcontrol.com/DW7700.pdf), due out Aug 15,
2005. This integrated modem handles the satellite negotiation, basic
network services (DHCP, DNS), firewall support, Quality of Service
routines, and other network acceleration protocols.  The modem also
integrates a v.90 56k dial-up modem in the event that a satellite
signal is temporarily unavailable. The modem also has a serial port
interface for ATM and credit card reader applications. Download speeds
can be up to 90Mbps and upload speeds can up to 1.6Mbs on a .98 or 1.4
meter dish.  Common service plans allocate up to a 1.5Mbs downlink and
512Kbs Uplink.

   Phone service is provided by using Voice over Internet Protocol
(VOIP) technology.  Simply put, this technology converts your voice
from a sound wave to a digital message.  This message is then
transmitted to through the internet to a server local to the location
you are calling.  The local server handles the local phone call and
also converts you're voice back into a standard signal.  When using
this service over a satellite internet connection, a small delay is
noticed.  This 1-2 second delay occurs because the signal must travel
from earth to the satellite and then return to earth.  This "lag" is
noticed while playing online games.  VOIP technology is fully capable
of providing fax service.
 
    There are separately sold installation kits for satellite TV
reception using the same dish.  The kits mount a second reception
terminal on the dish, and provide a second set of cable that can run
to a Dish Network or Direct-TV receiver.  Satellite TV plans are
purchased separately through the respective companies.

    Modern consumer satellite technology operates within either the
Ku-band or Ka-band.  The Ku-band refers to an extended frequency range
from 10.7 GHz to 18.4 GHz, while the Ka-band extends from 27 GHz to 40
GHz.  Commercial Ka-band satellites systems typically use the
17.7-20.2 GHz range for downlink transmissions (space-to-earth) and
the 27.5-30.0 GHz SHF frequency range for uplink transmissions
(earth-to-space).  The K-band frequencies create a smaller beam width
then the legacy C-band signals, allowing for smaller receiving dishes.
However, a narrow beam also makes the dish pointing tolerances much
tighter and is more susceptible to adverse weather.

    Power consumption on the DW7700 terminal is minimal, but greater
then what can be reliably provided by a battery for extended periods
of time.  Input power is available in both AC (90-264VAC) and DC
(12-24VDC).  The satellite radio component uses only 2 watts of power,
fed from the DW7700 modem. military Satellite radios typically last
for only a few hours on battery power.

    Cost of DirecWay Solutions vary with vendors and plans.  Most
vendors give you the option for purchasing the equipment in exchange
for a lower monthly fee.  If purchasing the required equipment
upfront, expect to pay between $300 and $600.  Fees range between $50
and $200 per month, depending on the amount of available bandwidth
desired and any optional features such as VOIP.

   The military is currently investing heavily in mobile satellite
communications for use in the future of warfare.  Over the next 5
years expect to see additional miniaturization of satellite
technology, and integration of satellite communication in to more
mobile applications, such as a moving vehicle.  I would not be
surprised if within the next 5 years satellite communications provides
internet service for back-packing and vehicle travel applications. 
Consider the advantages of a passenger being able to pull up data from
mapquest.com, while navigating via GPS and researching the final
destination. One of the factors holding this

I hope this answers your questions about satellite communications. 
This was meant to be more of a overview, rather then a detailed,
technical answer.  As for satellite service business ideas, consider
looking into military contracting.  The military is currently
invensting millions of dollars in-order to develop a communications
platform that can be integrated into a soldier's basic load.

Feel free to let me know if you have any other questions.

Para las comunicaciones satelitales existen los siguientes tipos: 
a- por el flujo ( mono-direccionales y bi-direccionales) 
b- por el tipo de satelites usados( baja orbita- LEO-,media
orbita-MEO- y geo-estacionarios.
c- por los equipos usados( con antenas parabolicas, antenas
helicoidales, con transceivers, modems, etc.
d- por el uso ( voz, data, video,scada, tv, musica,etc.) 
e- por la frecuencia usada ( bandas Ku , K ,etc)
El uso de satelites implica el pago de costos mensuales en base al
consumo x minuto, en el caso de los de voz , data y SCADA bajo el
parametro de "airtime", pero para los de musica y tv solo pagan una
tarifa mensual en funcion del numero de canales y el valor agregado
esta en el costo de peliculas de estreno(pay per view).
Sin embargo para las zonas alejadas, no solo en ESTADOS UNIDOS DE
NORTEAMERICA, sino en otros paises del mundo, el enlace mas codiciado
es el INTERNET SATELITAL y su costo esta en funcion  la velocidad de
subida y bajada asi como del tiempo utilizado.
Para toda America( desde Canada hasta Chile y Argentina, existen
satelites que son extraordinarios como el NAHUEL -1 (argentino-aleman)
y el SATMEX-5 ( mexicano)que tiene una presencia satelital en todo el
continente americano, ideales para obtener INTERNET SATELITAL.

Ellos, permiten el enlace entre el usuario que se encuentre en zonas
remotas, como la Amazonia peruana, brasilera o colombiana, el desierto
de Atacama, las selvas del Darien en el sur de Panama o islas alejadas
de cualquier contacto celular con tierra( ejemplo: Isla Lobos de
Tierra, Isla Lobos de Afuera en el Peru, pueblos andinos entre Bolivia
y Colombia, generalmente con un equipo que posee antena parabolica de
1.20 metros de diametro( precios varian desde 1800 a 3500 dolares).
Los costos de instalacion y "puesta a punto" varian desde 500 a 1200
dolares x equipo.

Estos equipos usan como enlace celeste , a estos satelies, que
re-direccionan la señal a estaciones terrstres, generalmente en USA,
llamadas "TELEPUERTOS" localizados a menos de 4 kilometros del anillo
de fibra optica USA.
Los telepuertos mas familiares estan cerca a Los Angeles, San
Francisco, Miami y Atlanta. De alli, la coneccion es directa al
sistema FIBRA OPTICA<==> SATELITES INTERNET.
Pero, como dice el amigo que hace la interrogante, cual equipo es mas
pequeño y de bajo costo, ademas de lo ultimo en tecnologia.
Estamos a la espera de que se ponga en la fase comercial el sistema
satelital ELLIPSO o el TELEDESIC. Estros dos sistemas sateiales de
baja orbita deberan efectuar su aparicion a fines del 2006 y
permitiran que cualquier usuario del planeta pueda tener internet con
solo un pequeno dispositivo similar a un telefono celular.
Directo desde el cielo.
Se acabaron los usuario de conecciones por cable, las comunicaciones
por estaciones repetidoras de micro-ondas, la fibra optica, etc, etc.
Ni hablar de las empresas de telefonia celular a nivel mundial, ya que
la transmision de voz via internet, usando el VOIP, habra superado la
calidad H-323.
Imaginese, que podran comunicarse con este nuevo celular de VOIP con
cualquier ciudadano del mundo donde se encuentre, usando un numero
mundial telefonico y a precios flat( comunicacion entre todos los
paises del mundo, sin tarifas, costosa x minuto y horarios.
De igual forma, el ciudadano del mundo si se encuentra en el desierto
del Sahara o en la espesura de la selva del Acre brasilero o tal vez
en el nevado Cotopaxi, o en la ciudadela perdida de los Inkas:
Machu-Pichu ( Peru), o si es miembro de una comunidad nativa de los
Shipibos en el rio Ucayali, podran recibir la señal de INTERNET
SATELITAL a costo flat y en alta velocidad.
Los pedidos seran de tal magnitud para usar estos dos sistemas
satelitales que los precios de los equipos seran bajisimos ( calculo
menos de 150 dolares )y el servicio de internet FLAT, podria ser del
orden DE 10 DOLARES MENSUALES.
Asi se podra democratizar este servicio de INTERNET, que ha permitido
la globalizacion mundial y yo lo considero una tercera revolucion
industrial de la humanidad.
Tal vez, hasta para fijar en el futuro una division historica de
edades o eras historicas, la era antes del INTERNET y la era INTERNET.
Sin embargo, todos estos servicios son en el area terrestre, pero,
que? del area maritima???
Aqui , podremos apreciar que para neutralizar los movimientos de
rolido, balance y encabuzamiento de un barco, bote pesquero o yate, en
alta mar, se requiere usar una antena estabilizada en los tres ejes
con una velocidad y afinamieto tal que , independiente del movimiento
del barco o bote, la antena, en base a pequenos servomotores mantenga
su "linea de mira" simepre hacia el satelite de internet deseado.
En todo el mundo solo existen dos empresas que en la practica han
acaparado esta tecnologia: la SEATEL  y la KVH. Susequipos son
excelentes pero... pero... sus costos de "airtime" son elevados y
fuera del alcance de muchisimos propietarios de embarcaciones.
Los precios de los equipos varian desde los 5,000 hasta 45,000
dolares, todos ellos, muy sofisticados y enlazados empresarialmente
con estas mismas compañias que actuan tambien como S-ISP, , es decir
usan para ellos toda la cadena de comercializacion del INTRERNET,
salvo la venta al menudeo o al usuario final , para las grandes cadeas
de venta minorista.
Existe una empresa China , que en menos de 4 meses, lanzara al mercado
americano del INTERNET-AT-SEA( OCEANICO)un producto con antena
estabilizada en tres ejes, de dimensiones muy pequenas, usando un
sistema de enlace satelital con los SATMEX-5 o el NAHUEL -1 usando un
telepuerto de San Francisco, y sus costos de airtime seran
verdaderamente revolucionarios, ni hablar del equipo en si, con lo que
pondra en serios aprietos a estos dos giganttes monopolizadores de las
antenas estabilizadas para uso maritimo mundial.
Esto , esta por venir en un futuro inmediato, asi que solo hay que
tener paciencia y que el socio del dueno de Microsoft se apure con su
sistema satelital.
Para terminar, estamos frente a una revolucion tecnologica llamada
WIMAX, que se enlazara con WIFI y las tecnologias ZIGBEE,  Bluetooth,
etc. integrandose con proyectos de satelites en bse a helio llamados
de orbita muy baja ( tenemos el STRATELLITE)que entrara en funciones
en menos de doce meses a nivel mundial).
Saludos y paciencia que lo bueno, recien viene , no para las grandes
empresas de comunicaciones satelitales, SINO PARA UD. AMIGO USUARIO..

Jim,

If the information posted by others regarding DirecWay isn't exactly
what you meant when you asked for state of the art in *mobile* sat
comm, I have additional information for you.

As you may have already figured out, the DirecWay service requires a
relatively large dish and is difficult to go mobile with unless you've
installed it on your RV.

The "state of the art" in mobile systems is currently claimed by GAN
operators such as Inmarsat.  The News Media is a big customer of GAN
services and use very small and portable terminals from companies such
as EMS Technologies (STORM terminal) to obtain enough bandwidth for
full video and audio conferencing.

Most all of the embedded journalists during the initial Iraq invasion
reported back to the U.S live via GAN systems.

Typical bandwidth of these systems is about 64K up and down.  Newer
terminals will allow you to double the bandwidth through a technique
known as "bonding" - but this requires two physical terminals.  The
frequency bands used are in the 1.5 GHz neighborhood.

The STORM terminals are about the size of a laptop and weigh 5 pounds.
 They typically transmit at around 5 Watts.  These state of the art
terminals will set you back about $7,000 up front and the monthly
airtime (or data charges) can easily climb to $200.

There are many other satellite data services available today that are
cheaper and smaller, but deliver much lower bandwidth or are less than
mobile.  If your idea is for a service that doesn't utilize a lot of
bandwidth, I can point you at very economical solutions.

As far as trends go, it's obvious that (like all things technological)
the terminals are getting smaller and the service is getting faster. 
Above and beyond the obvious, several providers are looking to follow
XM Radio's lead...

XM Radio uses a combination of Satellite and Terrestial transmissions
on their licensed frequencies to fill in the gaps caused by "Urban
Canyons" (when you can't see the sky for the buildings).  This is kind
of a convergence of cellular and satellite technologies.

The big roadblock to this here in the U.S. is that the FCC is less
than willing to allow just anybody to do this.  If the bureaucratic
issues are resolved, in five years time, we'll see devices that
operate on both terrestial and satellite networks with just one
transceiver card.