HRIT and LRIT Low-Cost System

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K3HTK
Posts: 1
Joined: Mon Mar 04, 2019 2:51 am

Re: HRIT and LRIT Low-Cost System

Post by K3HTK » Mon Mar 04, 2019 2:54 am

I have been trying to utilize the contact form on the USA-Satcom web page to figure out how to get this software. The contact page is not working. Is there another means to get a hold of him for this, or an email address someone has? Interested in using my SDRPlay RSP2 to get in the game! Looks very promising...

Thanks,
Ed
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usa_satcom
Posts: 1
Joined: Mon Mar 04, 2019 9:06 pm

Re: HRIT and LRIT Low-Cost System

Post by usa_satcom » Mon Mar 04, 2019 9:18 pm

Sorry the website contact form is not working. You can reach me (usa-satcom) using the email address in this PNG attachment.
Attachments
email.png
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Jaapyse
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Joined: Tue Apr 23, 2019 1:15 pm

Re: HRIT and LRIT Low-Cost System

Post by Jaapyse » Tue Apr 23, 2019 1:21 pm

Hi RSP2user,
Amazing project! I am currently working on getting it set up for me as well. I'm going to try receiving Meteosat-11, it's closer to me. This is the European/African equivalent and uses the same frequency.
What kind of tripod did you use? All of the ones I can find don't allow for a skew angle. Is it just a camera tripod? How did you attach the antenna to it? I'd love to see how you solved this.
- Jaapyse
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RSP2user
Posts: 108
Joined: Mon Oct 09, 2017 7:11 am

Re: HRIT and LRIT Low-Cost System

Post by RSP2user » Wed Apr 24, 2019 10:53 pm

Jaapyse,

The tripod was an old, inexpensive camera tripod that was stored in the garage. If you search the Internet for "camera tripod low cost" you will find similar tripods. The Premiertech ANT-GRID-24DBI comes with mounting hardware that will allow for adjustment of elevation and azimuth as well as 8 angles of skew when attached to a vertical post. The top of the old tripod was broken off, but provided a vertical mounting post, so the hardware that came with the antenna was just used to mount it to the vertical post of the tripod. No spectacularly challenging engineering feats were applied to mount the antenna to the tripod. The skew angle and direction to position the antenna were determined from https://www.dishpointer.com/ . Once the antenna was close to where it needed to be pointed and applying the appropriate skew angle, the next step was to attach the LNA/filter and use SDRuno to view the 1.6941 GHz signal and approximate the SNR (to get an idea if the signal could be adequately received) and further home in on the actual satellite position. The next step was to install and set up the image decoding software: either compile it from Github or obtain it from USA-Satcom (XRIT software) and receive GOES 16 satellite images from the continental U.S. Once the decoding software was installed, the signal quality, EbNo, and Viterbi numbers provided by the software could be applied to fine tune the antenna position and any other antenna attributes (e.g., tuning and reflector adjustments) and skew to ensure optimum reception performance. For use of the XRIT software with other satellites, contact USA-Satcom. If using the ANT-GRID-24DBI antenna, take note of the modifications described in this set of posts to have it work reasonably well at 1.6941GHz.

Let us know how your efforts work out.

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RSP2user
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Re: HRIT and LRIT Low-Cost System

Post by RSP2user » Wed Apr 24, 2019 11:16 pm

Jaapyse,

If you are located in Africa, a 1m grid parabolic antenna such as the ANT-GRID-24DBI may work for Meteosat 11 signal reception. If you are in Europe (particularly Northern European locations), you will likely need a larger parabolic antenna. If there are others in your area receiving the Meteosat signal successfully, get an idea from them what size parabolic antenna will work well. Also, note that a number of European operated geostationary weather satellites require additional decryption software from Eumetsat and a subscription so you should check local requirements, legal and otherwise for receiving such signals.

If you have an interest in weather satellite image reception and find that receiving the geostationary satellite images will be a problem, many of the same components (e.g., LNA/filter, RSP, antenna) can be used for reception of orbital HRPT satellite images. Refer to the post here: https://www.sdrplay.com/community/viewt ... f=5&t=2624 .

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RSP2user
Posts: 108
Joined: Mon Oct 09, 2017 7:11 am

Re: HRIT and LRIT Low-Cost System

Post by RSP2user » Sun Jun 23, 2019 9:03 pm

Update: simple modification significantly improves GOES 16 and 17 HRIT signal reception using Premiertek ANT-GRID-24DBI antenna. [This modification is solely meant for the Premiertek ANT-GRID-24DBI antenna. Application of this modification to other similar antennas may not have the desired results and is not recommended.]

The modification is to simply change the distance of the secondary reflector from the plastic feed housing to 1.681 inches. Note that the distance accuracy does not need to be within 1/1000th of an inch. If it is within 1/20th of an inch it should be good enough to see considerable improvement. This distance was arrived at through analysis of the antenna design and a significant amount of iterative testing. This is an optimized location for the secondary reflector of the Premiertech ANT-GRID-24DBI grid parabolic antenna when using it for GOES 16 or 17 signal reception at 1.6941GHz.
Antenna Secondary Reflector Standoff Mod.JPG
Antenna Secondary Reflector Standoff Mod.JPG (16.5 KiB) Viewed 3559 times
Here is the image of the stand-off (1.681" length acrylic tube I.D. 0.5: O.D. 0.75"). The black plastic end was made by turning a piece of 0.125" thick plastic using the drill as a lathe. The end piece was glued and press-fit into the acrylic tube.
IMG_1243 Feed Mod Component 6-23-2019.jpg
IMG_1243 Feed Mod Component 6-23-2019.jpg (39.4 KiB) Viewed 3559 times
Here is an image of the end of the modified plastic feed housing and an image of the bit used to grind it. The end of the feed housing was modified to slip the acrylic tube over it and use it as a mechanical support for the new extension piece. The acrylic extension was later painted with outdoor paint to ensure that it will last. The end of the existing feed was modified so that it would snugly fit up into the acrylic tube and the acrylic tube was then glued in place using epoxy.
Feed End and Bit 6-23-2019.JPG
Feed End and Bit 6-23-2019.JPG (41.96 KiB) Viewed 3559 times

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RSP2user
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Re: HRIT and LRIT Low-Cost System

Post by RSP2user » Sun Jun 23, 2019 9:16 pm

Here are the results using the described modification:

GOES 16
Before: Quality 95.1%, VT 76 EB/No 5.55dB (based on improvements described in the August 12, 2018 Post - the out-of-the-box figure without any modification was around Quality 69.7 VT 455)
After Mod: Quality 98.4%, VT 26, Eb/No 6.83dB
G16 Before and After.JPG
G16 Before and After.JPG (41.73 KiB) Viewed 3559 times
GOES 17
Before: Quality 77 on a good day (based on improvements described in the August 12, 2018 Post. The out-of-the-box without any modification figure would be significantly lower. Did not get images of the before shot, but the location is mid-U.S. so GOES 17 is a challenge with a 1m parabolic reflector antenna. Results were similar to those achieved with GOES 15 shown in the May 26, 2018 post.
After Mod and after accounting for skew and optimizing position: Quality 97.5%, VT 44, EB/No 6.26 dB

After:
G17 7.JPG
G17 7.JPG (62.38 KiB) Viewed 3546 times
GOES 17 skew optimization was done by modifying the bracket to allow fine tuning of the skew. The skew was optimized using this link https://www.dishpointer.com/ and then fine tuning the adjustment by hand while watching the USA-Satcom Dish Alignment feature of the XRIT Demodulator.
IMG_1249 bracket mod 6-23-2019.jpg
IMG_1249 bracket mod 6-23-2019.jpg (74.63 KiB) Viewed 3551 times

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RSP2user
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Re: HRIT and LRIT Low-Cost System

Post by RSP2user » Sun Jun 23, 2019 9:34 pm

Nice operation for a 1m grid parabolic antenna.
G16 and G17.JPG
G16 and G17.JPG (93.88 KiB) Viewed 3390 times

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