Satellites outside the Clarke Belt

[DefCon4]

Have there been any hobbyist attempts to derive content from the non-equatorial inclined or polar orbit satellites? I am aware the satellites outside the Clarke Belt in recurring orbits will require both elevation and azimuth steering. I have not been able to find a site with info on these sats.

 

[B.J.]

Have there been any hobbyist attempts to derive content from the non-equatorial inclined or polar orbit satellites? I am aware the satellites outside the Clarke Belt in recurring orbits will require both elevation and azimuth steering. I have not been able to find a site with info on these sats.

Well, if you're talking about regular TV type communications satellites, there aren't any polar orbit satellites. There are, from time to time sats that are in inclined orbits, but those seldom get inclined much more than 40 deg at the most, if I remember right, and I don't remember any of them actually having video on them if they were inclined more than about 6 or 7 deg. I think that they let them go inclined when they start to get low on fuel, and before they get completely out of fuel, they kick them out into a more distant orbit where they won't be in the way, and once they are out of fuel, they won't have any control over their solar panels or the direction of the antennas, so they aren't of much use.
The ones that are inclined are usually so indicated on Lyngsat. For example, they list Echo-4 as inclined now, but it's sitting in the same slot as Echo-8, so it's hard to tell when you're viewing Echo-4 and when you're viewing Echo-8. There are also a couple South American sats listed as inclined. If they are inclined more than a degree, you'll probably need a tracking program to tell you when the equator crossing times will be, if you can't track your dish.

Relative to non-communications sats that are high inclination LEO sats, there is also some occasional slow scan TV to be found coming from the ISS, but this is more like a series of still pictures. Whenever I've monitored them, it was just test screens, but I used to collect nice pictures from the old MIR space station. Also, there are APT style NOAA weather transmissions in the 137-138 MHz range. Not quite "video" but kind of neat to receive.

 

[Anole]

Molniya orbit, and others:

Not sure if you care, but the Russian orbital trick is fascinating.
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Also, the HAM radio world has had orbiting satellites for decades.
A quick Google search should find the appropriate sites.
Some of my buddies tracked and talked through them, but I was never interested in that corner of the hobby.

 

[delta_charlie]

Hi all, there are also ham radio satellites in low earth orbit (LEO) that are racing by at all times of the day and night. They have a very small footprint because they are so low and are moving very fast in relation to the surface of the earth. With a laptop and special software they can be tracked and found. I have managed in the past using nothing more then a small hand held beam antenna and a hand held radio to pick up voice contacts from these satellites. Some even have packet radio on them and pictures and other digital content can be pulled from them.

Because of the fast movement these satellites have considerable Doppler shift and are hard to stay locked on to with simple receivers. Special receivers for this type of operation are almost required.

If you want to learn more google "ham radio amsat"

Later, DC

 

[guapoharry]

Where BJ seemed to be going...

OP, could we talk a little more specific? -- like a type of bird to look at or some frequency of interest...

 

[DefCon4]

BJ: Thanks, I wasn't aware of what the notations on Lyngsat meant for ES4 and the 3 sats that service the Southern Hemisphere. As it states ES4's present inclined orbit to be -0.86 degrees with a max of 1.87, it must be a wobbly or skewed orbit that causes undependable reception for the DN-Mexico subscribers. Just as I started scanning the DX SWL airwaves years ago with a GCR, I thought it might be neat to chase some non-CBelt sats for some interesting content, but I'm not sure a multi-format video receiver is available for the hobbyist.

I just checked out NOAA APT, and it seems to be wide-band FM radiofacsimile which a much wanted ICOM can handle. I'll be spending some time at the HF-Fax website. I'll also be looking for software and hardware interfaces for controlling/powering both azimuth and elevation actuators on a C-dish.


Anole: Thanks, I find the Russian approach to advantaging the apogee dwell most innovative. Galileo and Kepler should be happy.


DC: Thanks for the link to amsat. I've been away from ARRL and QST for decades, but old interests are coming back.


Guapo: I tinker with RF and related hardware. I consider most processed TV content to be a waste of time, so I don't watch much. I do, however, spend some time investigating out-of-box approaches to satellite reception. I am not looking for any specific sat.

 

[B.J.]

BJ: Thanks, I wasn't aware of what the notations on Lyngsat meant for ES4 and the 3 sats that service the Southern Hemisphere. As it states ES4's present inclined orbit to be -0.86 degrees with a max of 1.87, it must be a wobbly or skewed orbit that causes undependable reception for the DN-Mexico subscribers.

I don't think that Lyngsat is very accurate in this case with respect to what is ON these sats, although possibly I see different things because I'm a different footprint. But Lyngsat is usually pretty accurate relative to the inclination because they usually have keps in the page that are less than a week old. For example, I just extracted the keps from Lyngsat's sattracker page...
<param name="bird" value="EchoStar 4 ">
<param name="tle1" value="1 25331U 98028A 09213.40177840 -.00000248 00000-0 10000-3 0 290">
<param name="tle2" value="2 25331 1.2055 50.8591 0005056 66.9107 259.8297 1.00269744 41260">In the second line the 09213 means the 213th day of 2009, which I think is 6 days ago. In the third line, the 1.2055 is the inclination.
I don't see where you got the 0.86 inclination for ES4 (I assume you mean EchoStar 4) and don't see the mention of 1.87. All I saw was the (incl 1.2 deg) note.
Relative to the wobbly orbit, generally inclined orbits like this are described as being "figure 8" shape. During each 1 day orbit, it will go it's inclination (1.2 deg) above the equator, and below the equator, and will also drift a bit east and west of it's center location along the Clarke Belt. You can feed the keps into lots of sat tracking programs, I sometimes use a crude one I wrote, but usually use an old DOS program that I trust more to be accurate, which is called Trakstar, written by T.S.Kelso ( CelesTrak: Satellite Tracking Software by T.S. Kelso ). It does not have the fancy graphics of some programs, but you can trust it's accuracy, which is not the case for many of the fancy programs (some programs work fine for LEO sats, but not for the geostationary sats). Kelso also has up to date Keps for the sats on his page. I just plugged in the current Keps from the Kelso page into TrackStar, and it shows the following time( EDT)/lat/lon pattern:
19:29 0.0 77.16 W
01:29 1.2361 S 77.25 W
07:06 0.1120 S 77.29 W
07:28 0.0 77.29 W
13:27 1.2362 N 77.22 W
17:30 0.5975 N 77.17 W
19:25 0.00 77.18 W

Ie a very narrow "8" perhaps, ie a total swing of 2.7 deg in latitude, but only .13 deg in longitude. The equator crossing times are getting earlier each day. By 3-4 minutes.

Just as I started scanning the DX SWL airwaves years ago with a GCR, I thought it might be neat to chase some non-CBelt sats for some interesting content, but I'm not sure a multi-format video receiver is available for the hobbyist.

Thes "video receivers" we use will only work on the Communications sats. THe ones off the Clarke belt aren't very far off the belt in the inclined orbits described above, otherwise they have probably run out of fuel or perhaps are in one of those Russian style Molynia orbits mentioned above, if they are still doing that.

I just checked out NOAA APT, and it seems to be wide-band FM radiofacsimile which a much wanted ICOM can handle. I'll be spending some time at the HF-Fax website. I'll also be looking for software and hardware interfaces for controlling/powering both azimuth and elevation actuators on a C-dish.

The NOAA APT is really a medium-bandwidth, somewhere around 50 KHz wide. I used an ICOM 7000 to receive it, but it had bandwidths narrower, around 15 KHz, and wider, around 100-150, but not one at 50, so I bought a special adapter that would do the 50 KHz bandwidth. However the 15 KHz bandwidth on the ICOM was really OK.. you just lost a bit of the gray scale spectrum.
For the NOAA sats, you don't need a dish. I used a home-made Lindenblad antenna, as well as a commercial circular polarized YAGI. The Lindenblad didn't require aiming. The Yagi gave more gain, but I had to aim it at the sat, which was cumbersome, either hand held or via two TV tenna-rotors, on for Az and one for Elev. There are also GOES sats that are Geostationary, that DO require a dish. They don't require Azim/Elev tracking, but they do require a different feedhorn to get the lower freq ( I think it's around 1700 MHz ). I've never done the GOES sats.

The SSTV stuff I mentioned was HAM stuff, sent down by HAMs on the space station and before that from MIR. But it's not real video to me, more like just pictures. There are shareware programs to decode it on a computer, and you can use a conventional scanner or an ICOM type communications receiver, with nothing more than a Discone antenna.


EDIT: Re the APT stuff above... years ago, back in the analog days, Associated Press, and UPI used to have narrow band signals on the TV satellites that carried APT style news pictures, ie the type of pictures you'd see in a newspaper. Some were color some were B/W. There also used to be re-transmissions of the APT from the GOES satellites, in a slightly different type APT called GOES-TAP I think, but my APT program did both formats. There used to be a LOT of so called "Hidden Signals", on the TV satellites in a variety of different formats, but most of those have been replaced by just sending stuff via DVB or other digital formats, often via IP/DVB. Usually easy to lock the signals, but difficult to decode.

 

[Jim S.]

I haven't read anything about GOES for a long time, but I think they stopped analog transmissions a few years ago. I don't know whether there's been any amateur reception of the digital transmissions or not. At least some of the data should be public-domain, but the cost of the demodulator hardware may be prohibitive for the hobbyist. The polar-orbiting satellites are also transitioning to digital, but the last time I checked there were still mostly analog ones in operation.

 

[B.J.]

I haven't read anything about GOES for a long time, but I think they stopped analog transmissions a few years ago. I don't know whether there's been any amateur reception of the digital transmissions or not. At least some of the data should be public-domain, but the cost of the demodulator hardware may be prohibitive for the hobbyist. The polar-orbiting satellites are also transitioning to digital, but the last time I checked there were still mostly analog ones in operation.

Thanks. I didn't know that they had stopped the analog stuff. Several years ago, I bought a LNA for the 1.7 GHz signal, and was intending to build one of those coffee can feeds, but I never found the time to try that. Typical of me, I get started on all these projects, and never finish any.