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Old 08-04-2015, 12:38   #16
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Re: Receiving Weatherfax Directly From the Satellite

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Originally Posted by conachair View Post
I've had readable images (just) using an icom ic7000 and wxtoimg with just the backstay as an antenna. The software is very cool, it auto tunes the icom as the satellite passes to compensate for Doppler shift.
Not really wide enough bandwidth, though maybe a quadrifiler antenna would make it useable. Great fun!
A QFH would do the trick , I have one at Campo Pingo but for use afloat they are a bit bulky compared with a 'turnstile' which would also be simpler to make yourself.

I picked up two professionaly made QFH's for 99c the pair on Ebay a while back - someone had bought a fancy motor boat and thought they were 'ugly' - a bloke has to have the occasional win
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Old 08-04-2015, 13:53   #17
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Re: Receiving Weatherfax Directly From the Satellite

Dockhead,
I need to be brief, more later...

The answer is yes, I have...
Quote:
Originally Posted by Dockhead View Post
Has anyone received these satellites directly? I doesn't sound like it would be that hard -- a UHF ham transceiver, a small yagi antenna . . .
In actuality the first time I did this, was over 30 years ago....
And, I also worked on the RF part of a Univ of Florida project on this in the late 80's as well...(I'm not a software guy!)


More later, but I assume that everyone else will have already chimed-in with most of the info by then...

John
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Old 08-04-2015, 14:04   #18
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Re: Receiving Weatherfax Directly From the Satellite

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Originally Posted by El Pinguino View Post
Thankee... my favourite ever is 'The Trombone'... see below ( the yellow '+' marks the ship's location).

(...)
Your trombone is a thing of beauty!

THX for sharing!

barnakiel
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Old 08-04-2015, 18:31   #19
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Re: Receiving Weatherfax Directly From the Satellite

I know it is a bit off topic but I am thinking of the Iridium Go satellite system.
Me think it is the future.
Cheers
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Old 08-04-2015, 21:53   #20
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Re: Receiving Weatherfax Directly From the Satellite

Pinquino:

Well, you asked. This isn't a terribly tough project for a hardware hacker although it does require attention to detail and a knowledge of motor control circuits. Googling motor control fet returns some great ideas.

STEVAL-MKI127V1 Ultra stable 3-axis gyro based on the L3GD20
STEVAL-MKI127V1 Ultra stable 3-axis gyro based on the L3GD20 - STMicroelectronics
It's $90.65 (probably plus shipping) and is the heart of a stabilized antenna mount (or drone control, or anything that needs 3 axis control). For the complete user manual and PC tools (intuitive, easy-to-use software for detailed user programming and graphical real-time data monitoring), download from:
BL-3GMod advanced RC aircraft gyro detail page

This is enough help for one day. By the way, it only took about 10 to 15 minutes to find that gadget from a cold start on the web.

Yes, it probably is beyond the scope of this forum but what else do you have out "there" but time? It is rather cool to watch the boat rock and see the antenna keep pointing where you aimed it. An antenna controller based on phase comparators (an auto direction finder) is another way to solve the stabilization problem without a MEMS device. Aim the antenna at the satellite, receive a signal and switch on the controller and the antenna is then always pointing at the signal, no matter what pitch, yaw or roll the boat is doing, barring capsizing or sinking, of course. It is the same principle sometimes used for missile lock.

Later...
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Old 09-04-2015, 09:48   #21
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Re: Receiving Weatherfax Directly From the Satellite

Dockhead,
As I predicted, by the time I got back here, you'd have the info needed....and CarstenWL, Paul Elliot, and El Pingunio, have given you the detailed info...(especially El Ping's caution about trying some dongles on APT reception at sea....)
But how about I give 'ya some real-world tips...
Quote:
Originally Posted by Dockhead View Post
"The most interesting signal sources of AM-FAX are mainly the weather satellites (NOAA-Satellites on 137 MHz or the geostationary Meteosat 5 or GOES (USA) on approx. 1.7 GHz.

"To receive these satellites, it is recommended that a special receiver is used with an IF bandwidth of approx. 30-50 kHz. For the 1.7 GHz band, a small dish or Yagi-antenna with a low noise LNA or LNC will also be required.
Meteosat 5 for example, transmits almost continuous IR and VIS pictures with a resolution of 2.5 to 5 km in a format of 800 x 800 pixels. Many programs are able to automatically sense the beginning of each picture by using additional digital information, and to make very impressive weather films. These films are interesting not only for amateur meteorologists, but also for sailors, mountain climbers etc."


Has anyone received these satellites directly? I doesn't sound like it would be that hard -- a UHF ham transceiver, a small yagi antenna . . .

1) First off reception of the 137mhz APT signals are pretty easy to do, whether on-board at sea, or on shore....

The most important thing (other than the antenna!) is using a good wide-bandwidth receiver....(Hamtronics R139 is a good unit, not sure they are still available???)
And, while some wide-range receivers (like the Icom 1500) do work okay, most VHF/UHF ham radios do NOT....the receiver bandwidths are TOO NARROW...

Have a look here at some reviews...
http://www.arrl.org/files/file/Techn...0Receivers.pdf

Hamtronics R139 Product Reviews




2) A turnstyle antenna is fine, assuming you are using a good rec and a short run of coax (which is all you can use on a boat!)....
But, yes a QFD antenna is better...but bulkier...

3) The APT images are very nice to have in areas with fast moving weather systems and few (or unreliable) forecasts, such as high-latitude sailing (or polar regions)....
And, those sailing the Southern Ocean find having these images to be of great help!!
(but, for other areas where forecasts are better and readily available....these images are just a luxury for most..)


4) Trying to design and use a 1691mhz system for on-board use on anything but "mega-yacht" sized boats is probably going to be a big mess....the open space needed, etc. as well as the power consumption and equipment costs, etc. make the undertaking something for experimenters or those on big boats...
(think of this as sort of a "receive only" version of INMARSAT FB 250)

Understand that the GOES images that you'd get from these satellites, as well as the WeFax charts transmitted by them, etc. are all available for free over HF radio multiple times each day....so if you already have HF radio (even just a HF receiver), then you gain nothing...

BUT...
But, the LOES images (APT images) that come from the LEO satellites (NOAA 17, 18, etc.) that you'd receive on a 137mhz turnsytle and dedicated APT receiver, are unique and might be of some use to you...
And, that does NOT require long boom yagi antennas / dish antennas, antenna tracking, low-noise LNA's, etc...



If after reading everyone else's info / threads and you're still interested in doing this....use my tips above, and have fun!


BTW, while I've heard the same, that the US budget constraints are keeping any new LEOS satellites from being built/launched.....I'm not sure this means the system is only good for the next few years...
But, I wouldn't spend a lot of money on the stuff, in any case...


Fair winds..

John
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Old 09-04-2015, 13:23   #22
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Re: Receiving Weatherfax Directly From the Satellite

I bought the Raymarine Sirius Receiver for receiving weather data, but it is for North America only. Why can't this device work in the rest of the world or why don't other governments offer the same service.

Having a weather overlay on top of radar and the chart was great. Now I am in Europe and have to live with Navtex.
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Old 09-04-2015, 14:53   #23
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Re: Receiving Weatherfax Directly From the Satellite

Quote:
Originally Posted by trifan View Post
Pinquino:

Well, you asked. This isn't a terribly tough project for a hardware hacker although it does require attention to detail and a knowledge of motor control circuits. Googling motor control fet returns some great ideas.

STEVAL-MKI127V1 Ultra stable 3-axis gyro based on the L3GD20
STEVAL-MKI127V1 Ultra stable 3-axis gyro based on the L3GD20 - STMicroelectronics
It's $90.65 (probably plus shipping) and is the heart of a stabilized antenna mount (or drone control, or anything that needs 3 axis control). For the complete user manual and PC tools (intuitive, easy-to-use software for detailed user programming and graphical real-time data monitoring), download from:
BL-3GMod advanced RC aircraft gyro detail page

This is enough help for one day. By the way, it only took about 10 to 15 minutes to find that gadget from a cold start on the web.

Yes, it probably is beyond the scope of this forum but what else do you have out "there" but time? It is rather cool to watch the boat rock and see the antenna keep pointing where you aimed it. An antenna controller based on phase comparators (an auto direction finder) is another way to solve the stabilization problem without a MEMS device. Aim the antenna at the satellite, receive a signal and switch on the controller and the antenna is then always pointing at the signal, no matter what pitch, yaw or roll the boat is doing, barring capsizing or sinking, of course. It is the same principle sometimes used for missile lock.

Later...
Thanks for that... you had a head start in that you knew what you were looking for.. I am now an expert on moths...

It sounds like a fun project... one really does need an antenna that people have to stop and ask ' wot's that??' and turnstiles and QFH don't do that any more....
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Old 09-04-2015, 15:00   #24
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Re: Receiving Weatherfax Directly From the Satellite

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Originally Posted by ka4wja View Post
.................

BTW, while I've heard the same, that the US budget constraints are keeping any new LEOS satellites from being built/launched.....I'm not sure this means the system is only good for the next few years...
But, I wouldn't spend a lot of money on the stuff, in any case...


Fair winds..

John
From what I can discover ( there is just way too much info available out there and I just end up with a headache) the present analog sats will be replaced with digital LEOs transmitting something known as LRPT...but they have run into problems with them...from wiki Low Rate Picture Transmission - Wikipedia, the free encyclopedia

"The initial investigations regarding the interference on MetOp-A HIRS have been completed, and the conclusion is that no scenario exists where LRPT on MetOp-A can be turned on without causing heavy interference on HIRS. Due to the operational importance of HIRS and the lack of an established LRPT user community, it is clear that LRPT will not be turned on again operationally on MetOp-A." - Announcement to NOAA from EUMETSAT on 5 February 2007[1]'

'The previously mentioned MetOp program intends to launch satellites every five years, but due to problems encountered with the LRPT transmitter on Metop-A and the infeasibility of rectifying these for Metop B and C, it has been decided to discontinue the LRPT operational service.'
''Although it is currently being flown on MetOp-A, LRPT has been permanently deactivated on that vehicle after causing interference with the High Resolution Infrared Radiation Sounder (HIRS) sensor.'

As they say 'Watch this space'.....

Ping
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Old 09-04-2015, 21:15   #25
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Re: Receiving Weatherfax Directly From the Satellite

This would appear to be the future....
http://www.goes-r.gov/downloads/2014...2/goldberg.pdf
I wonder if we will be able to receive and decode directly.....
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Old 10-04-2015, 07:18   #26
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Re: Receiving Weatherfax Directly From the Satellite

George,
I have the answers for you...
Much of this you are probably already aware of....but for clarification and for anyone else's education...

a) The governments of many/most of the world's sea-going 1st world nations, DO provide this information/forecasts to mariners, sailors, etc., all for free!!
Nowadays, it is usually disseminated in multiple ways, such as HF radio broadcasts (HF WeFax, HF SITOR/text, and HF Voice), worldwide satellite broadcasts from INMARSAT-C (SafetyNet broadcasts), the internet, LW/MF broadcasts, etc...
http://www.nws.noaa.gov/om/marine/rfax.pdf
http://weather.noaa.gov/fax/marine.shtml
http://www.nws.noaa.gov/om/marine/home.htm

Offshore / Hi-Seas Weather data / forecasts

https://www.youtube.com/playlist?list=PLnN6ygtZ3h2mPZAx2vWzdjTJjHlChruyY

And, since in the Med, you have easy reception of the UK and German (GYA and DWD) broadcasts, as well as plenty of terrestrial-based data services (mobile phone / wireless) that give easy access to the internet....and since passages in the Med are typically only a few days long / or a few days between terrestrial-based internet connectivity, etc. NAVTEX fills the niche nicely...and of course, like the HF WeFax broadcasts, is FREE...



b) The Sirius Marine Weather Service is, of course, a private, non-governmental, service....
Ironically though, their weather service provider, WSI, uses primarily the US NWS/NOAA marine weather products....surface charts, wind&wave charts, etc. as well as US NWS NEXRAD images, etc...

And, as the Sirius system is designed for use with Sirius network / Sirius satellites (S-band) specifically licensed for use in region 2 / N. Amer., rather than L-Band mobile sat broadcast band licensed in region 1 and 3....although as there are no longer any operational satellite radio broadcast sats being used for sat radio broadcasts, there is little chance that a similar service would ever find a viable market outside of the US / N. Amer....


Quote:
Originally Posted by George DuBose View Post
I bought the Raymarine Sirius Receiver for receiving weather data, but it is for North America only. Why can't this device work in the rest of the world or why don't other governments offer the same service.

Having a weather overlay on top of radar and the chart was great. Now I am in Europe and have to live with Navtex.
Have a look at the above referenced info, and especially watch these videos, as this info/forecasts work worldwide, are easily accessible, etc. and are free...

https://www.youtube.com/playlist?list=PLnN6ygtZ3h2mPZAx2vWzdjTJjHlChruyY



I hope this helps...

Fair winds..

John
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