MobileInternetSatellite.com

I've collected information and URLs over the past year ... from postings on several forums for RVers with two-way satellite systems. I hope you find this useful!

And, don't forget there are more links on the RVNetworking.com Links page (though I don't guarantee no repeats! :
http://www.rvnetworking.com/Links.cfm

Max said:
Here is an excellent site for a tremendous amount of info on satellites:
http://www.geo-orbit.org

Scroll up and down, check out the links....an amazing amount of info is
there.

Here is another very interesting site with lots of good satellite information:
http://www.satsig.net/vsat_top.htm

Stan at Cox said:
Q: Let me see if I got this right: Different birds use different transponder carrier frequencies and hence can be identified by that characteristic? So, if I happen to find an unknown bird and spot a particular carrier or group of carrier frequencies, I can look up a data table and figure out the satellite’s ID. Is that correct?

Max said:
A: Correct. Here is another geo-orbit reference, in this case focusing on the eastern hemisphere:
http://www.geo-orbit.org/easthemipgs/easthemp.html#anchor99838

Buried in there under the tables that list the various sats is transponder info. You will notice that most satellites have an identifier beacon. You can use this to locate the specific sat with a spectrum analyzer or, like the BirDog does, tune to the center point of a specific transponder frequency

One of the things that I've wondered about is where the LO signal comes from. It would be easiest for it to be in the LNB, but that makes a pretty severe temp stability requirement for it. If the LO isn't dead on, then the IF to the receiver doesn't mean a lot. While an AFC can recover a wandering IF's modulation, it obscures the carrier by the drift of the LO.

It is an amazing thing to me that such a tiny LNB can provide a stable LF over such an amazing tempperature range, but apparently that is the case. The local stability is apparently about +/- 1 MHz. If you go to the sites of the various LNB manufacturers, each lists the LF for most if not all of their LNB's. For instance, the New Japan Radio company is one of the largest. It supplies the Gilat LNB's which StarBand uses:
http://www.njr.co.jp/e05/e_mc_ku.htm

Let me qualify all this by saying that I am not an engineer and I have no formal training in any of this stuff, but I have been involved in it ever since my teen years, when I worked for the Seaboard Electronics Corporation in NY. I am a tinkerer by nature and have always known just enough to get me to the next step or get into deep dodo trouble and fry all my equipment, which I have proudly done on many occasions.

Don Bradner said:
They represent power output from a particular satellite, listed in dBW. As a general statement, with the .74 meter dishes, most of us need 46 dBW or higher, to work well. Power doubles roughly with each 3 dBW change.

The problem with the footprint maps is that they are inexact in several ways. First, nobody has gone to all of the locations in North America and actually measured signal strength. Second, no two transponders on a given satellite have the same output, so the map is at best an average.

The lines on footprint maps are typically dBW, and 3 dBW increase equals doubling of power. So, if you are somewhere that is 50 dBW, and you move to an edge where all you get it 47dBW, that is half the power. The Direcway Signal Strength meter is not actually signal strength, but rather signal quality of which part is strength, so you don't necessarily see a doubling/halving effect in that scenario.

If the map shows a 49 dBW, it will almost certainly work. A 44 dBW, it almost certainly won't. The 46 dBW level has to be considered a "maybe". We look to user experience wherever possible, to refine the maps at the fringes.

Two examples: First, the SatMex5 maps show that the signal should go all the way to the border NW of Seattle. Actual user experience amply shows SatMex5 is dead at any point from Olympia north and west. Second, we talk a lot about how good G11/91 is, but one specific transponder (frequency 990) on G11 is known to have some 19 "holes" in North America, including Minnesota and Texas.

Don Bradner said:
I have never seen published numbers. That doesn't mean I won't take a shot it, though!

Based on relative reflective surface area, the equivalent signal should be achieved at about 44 dBW and 42 dBW, respectively, with the larger dishes.

Max said:
If you look at the http://www.geo-orbit.org web site, you can get to pages for each sat that show relative dish size vs dBW. For instance check this one out for IA-7 or as it used to be known, T-7 at 129 W. IA-7 is used by Starband and has a pretty hot footprint for a .75 meter dish well into Mexico, all of the USA, Hawaii, the Bermudas, and a good distance into Canada.

http://www.geo-orbit.org/westhemipgs/ft7p.html

Here is another footprint map for IA-7:
http://ww2.intelsat.com/flash/coverage-maps/sat_foot.html?sat=G-27%20at%20129%BA%20W&display=map&spot=1

And, here is the page for all Intelsat maps:
http://www.intelsat.com/flash/coverage-maps/index.html

For lots more satellite maps, go to Don Bradners forums on http://www.datastormusers.com and search in the forums.

I searched on the keyword "footprint" and on "ia8" which is our Direcway satellite. I found lots of information, including a good footprint map.

My experience with hundreds of installs shows that the 46 dBW line is a fairly accurate cut off point for use of the .75 meter dish. When the lines start getting close together, just like on a topo map, the signal strength drops off dramatically and quickly. This is called the cliff effect.

You can see that on the Baja map, the cutoff point is near Mulege and experience shows this as correct. It may well work south of there but you will find that you will lose signal during the day between about 10 AM and 6 PM, as the signal is drowned out by background solar noise.

With a .98 meter dish, a StarBand user is pretty much guaranteed service well into just about all of Mexico, Canada and Alaska.

Naturally a 1.2 meter dish will give you a better rain fade margin on the extreme edges of the foot print.

The dBW values quoted above are valid with an LNB that has a noise figure of .8. You will do better if your noise figure is less than that. In general, I would strongly recommend anyone contemplating a two-way VSAT system ensure they are getting an LNB figure of .7 or below, with .5 being the best.

If you search around you will see .8 Ku band LNB's for about $49, whereas a .5 is on the order of $125. Once again you get what you pay for.

StarBand now ships all OCONUS (outside the continental United States) systems with a .5 or .6 LNB.

Don Bradner said:
All Satellites have "holes". The only one with a Seattle hole is SatMex5. The ones with Florida holes are AMC3 and Horizons 1.

That would leave 4 birds now, plus one coming, but at any given moment you may not to be able to get on a particular one. Probably AMC9 would be the easiest/best.

Lameelk said:
SatMex5 worked well for us on a trip to Nova Scotia. We used it all the up to the edge of Prince Edward Island.

Also, I connected in Washington state along the coast, but admittedly did not try around Seattle.

Mike said:
This past summer I traveled with my dish north from Denver, through Wyoming, and then along interstate 90 as far as Missoula Montana. I am on 117 and had no problem whatsoever in Missoula getting connected. I then traveled west on Route 12 across Idaho into Lewiston, Idaho and along the Columbia River gorge into Portland. I did not have any trouble getting connected in any of these places.

If you look at the footprint of 117, the signal does fade in the very Western states, but by the time you hit the Dakotas, the signal begins to creep into southern Canada, so you should be OK in the Dakotas and eastward.

Gregg said:
I have used my 117 as far north as Sequim and in Seattle. The system drops off more often, but is usable. You have to cross-pol using a different transponder, if yours is too weak.

Stan Miller said:
North of Bremerton to Spokane, Washington over to Kallispell, MT and along that line going east, 117 is iffy. You can usually fiddle enough signal strength to get online, but passing cross-pol becomes a real problem.

Max answered:

Well I want to say “yes” that it will work with a standard antenna, but it seems to be right on the edge. Look at these two maps:
http://www.google.com/maps?li=lmr&hl=en&q=sask+canada+loc:+Regina,+SK,+Canada&num=10&hl=en&ie=UTF-8
and here is the footprint for IA-7:
http://www.geo-orbit.org/westhemipgs/ft7p.html
Follow the line you see intersecting about midway down the Baja peninsula. It's incorrectly marked 46 dBW right there – if you move west along this line, you can see it is actually 44 dBW. Anyway, follow it up around Canada and you will se what I mean. I do have a customer just a tiny bit southwest of Calgary that is working fine on a .75 meter dish.

I would not want to guarantee it. A .98 meter dish would work, in my opinion.

Max answered:
No problem with a .75 m dish on AMC-4/101 W. I have several customers all the way at the northern end of Hudson Bay running just fine. And, Starband is now allowing 481's and 484's on AMC-4 again. Just new accounts.

It's iffy on IA-7.

The biggest problem of mobile customers in that area on IA-7 at the 129 degree orbital slot (aside from a weak signal) was the low elevation angle to the bird. Add to that the preponderance of trees and hilly/mountain areas, and it can be hard to get a good line-of-sight.

AMC-4 at the 101 degree orbital slot has a higher look angle. For example, for Horizons 1, it is going to be 24.4 degrees and on AMC-4 it will be just a hair under 33 degrees.

AMC-4 has pretty good coverage also. Anywhere inside the 45 db line on this Ku chart should be good.

http://www.geo-orbit.org/westhemipgs/fge4p.html

Bill Joyce answered:
Using a Direcway .74 meter dish on a tripod assigned to satellite 127 (Horizons-1), it worked fine in Ignace, Ontario in September. Ignace is fairly close to Dryden.

Lee said:
I just got back from that area - Bahia Conception to be exact. AMC9 worked fine but the ss was going down so I don't know how much further south it's viable. We went as far down as Puerto Escondido and it was weak but usable there.

LeRoy said:
I am on G11 (91) and got commissioned in Montana and gone as far south as Mazatlan.

Jan said:
We used 99 as far down Baja as Mulege and in some parts of Canada and in Nova Scotia.

Scott, Barb, Mutley, & Tinkerbell said:
I don't think 99 will go much south of Mulege on the Baja and Mazatlan on the mainland, but works way north. We will have a reading on IA8-89with a 7000 from LaPaz in two month.

- Stan said: Here is a very cool graphic showing G4's location:
http://homepage.mac.com/paultahoe/.Public/g4r.jpg

- This website allows you to see the earth from a satellites perspective. For example, select GE4 from the list of satellites and click View Earth from Satellite to see what GE4 can see:
http://www.fourmilab.ch/earthview/satellite.html

- This website allows you to track a single orbiting satellite in real time:
http://liftoff.msfc.nasa.gov/RealTime/JTrack/3d/JTrack3d.html

From Stan Miller:
There was some concern here about hiding your current location from DW and I mentioned that all you had to do was provide a latitude/longitude point that was an equal distance from the satellite, as your current location.

The following URL will take you to the chart is for 99 W. Similar maps exist for all of the satellites:

http://www.lyngsat.com/tracker/g4r.html

Looking at the map, you can see that you could be located anywhere around a very large circle, as far as the location you enter into the registration software.

Chris Woodard created what he calls “time maps” for most of the satellites:
My system thinks I'm in Sellers SC.....on a line of equal time ..... therefore, all DW knows as to our whereabouts is we are somewhere on the Arc line ..... that's my guess anyway.

Timing maps: http://groups.yahoo.com/group/klaputt/

Max said:
In the early days when StarBand first came out, the modems were not auto-ranging and depended on a set delay the NOC manually assigned.

My wife and I were trying to find a way to get the modem to work down at the tip of the Baja peninsula. She did the math and I constructed a crude spreadsheet to calculate the arc. I posted this info a while back on the Datastormusers.com forum, in case anyone wants to see how to calculate this magic arc. If you stay in it, then you can move thousands of miles without changing your delay/zip code.

http://www.datastormusers.com/ubb/ultimatebb.php?/ubb/get_topic/f/1/t/000828/p/2.html#000019

It produces real-time displays of where any Satellite is, and predicts passes for your locale. There are about 8000+ satellites in orbit, a lot of these are just junk and debris such as discarded rocket bodies, but quite a few are working Satellites.

Their positions can be calculated very accurately using pure maths, no need for a huge radar dish in your back garden. Satscape will do the maths for you, and present their positions in a nice graphical way. Passes over your part of the world can be predicted weeks in advance in a matter of seconds.
[url]Here is the URL: http://www.satscape.co.uk/[/url]

Don said:
There are several online solar outage calculators, including this one from Panamsat, the owner of the G4R, G11, G3C satellites and half-owner of Horizons 1:
http://www.panamsat.com/global_network/calc_sun_outage.asp

There is some info about solar outages on this page and a link to the calculator.

You can go directly to the calculator with the following link:
http://www.panamsat.com/global_network/calc/sun_calc.asp

Satellites they don't own can still be calculated by entering:

- The satellites longitude (i.e., AMC3 is 87 W, AMC4 is 101 W, and so on)
- Use the 1.1 meter size.
- Select KU band.
- Pick a city near you.
- Pick season = Fall and the year.
- Choose your local time zone
- Click Calculate.

Find out more about solar outages:
http://www.panamsat.com/global_network/solar_activity.asp

At 10:54 am in Organ Pipe Cactus National Monument my connection failed - IA8 on a 0.74m dish using a DW7000. The signal strength was 30 and by 10:57 it was operational and signal strength had climbed up to 57 and at 11:00 am it is at 66. I went outside and sure enough the sun was right behind the dish. Much better experiencing it than reading about it on this newsgroup a few days ago.

Arrrggghhhh!!! Not solar flares, it is just one of the to times each year when the sun, your satellite and your dish all line up and the radio frequency noise from the sun gets louder than the signal from the satellite.

Same thing happened to me yesterday; about the same time, but so far, not today. I know this is the solar flare time of the year but I'm too lazy to check the calculator...

I have some interesting screenshots of my program while experiencing various things happening to the signal strength. They were interesting to me anyhow. Here's the URL:
http://www.redroadsliving.com/html/dw6kss.htm

It is also a good time to calibrate your DW6KSS program for the signal droupout level. It certainly beats going to Oregon and waiting for a rainstorm!

Here is a link for a solar outage calculator:
http://www.panamsat.com/global_network/calc/sun_calc.asp

---- Date -----| ---Start ---| --- Peak ---| --- End --- | Duration
mm/dd/yyyy| hh:mm:ss | hh:mm:ss | hh:mm:ss | mm:ss
--------------+------------+------------+------------+------------
03/09/2006 | 10:42:20 | 10:53:40 | 11:05:00 | 22:40
03/10/2006 | 10:42:47 | 10:53:24 | 11:04:02 | 21:15
03/11/2006 | 10:43:38 | 10:53:11 | 11:02:43 | 19:05
03/12/2006 | 10:44:49 | 10:52:52 | 11:00:55 | 16:05
03/13/2006 | 10:46:46 | 10:52:36 | 10:58:26 | 11:40
(all times local)

Solar outages occur for a week or two, twice per year, when the sun passes directly behind the satellite and overwhelms the signal.

The times given above are when some signal degradation can be expected; actual loss-of-service will depend on prior signal strength.

Arizona time.