Nice LRPT image and QFH. The amount of gain required by your antenna depends on factors such as your location in relation to the geostationary satellite (distance), the transmitted power of the satellite, and the SNR and gain of your LNA. There are European weather satellites that are designed to transmit HRIT and LRIT images, such as Meteosat 8, 9, 10, and 11 (HRIT on 1.69515 GHz and LRIT on 1.691 GHz). You will need to research Eumetsat for active geostationary weather satellites, transmission times, and whether or not broadcasts are encrypted, requiring payment for a decoding key/unit. There are global software developers who may be able to provide additional information for you with respect to receiving images from European geostationary weather satellites. These developers contribute to the Open Satellite Project and you can find them here – https://github.com/opensatelliteproject
. As far as off-the-shelf antennas, the L-Com Hyperlink Brand HG1922EG 1 meter grid antenna (22 dBi gain) has been found to work well receiving signals from GOES 16 from as far away as Ontario, Canada and also note that M2, Inc has a 1625 MHZ to 1725 MHz Yagi antenna (18 dBi standard) and you may want to contact them to see if they can modify it to provide additional gain (http://www.m2inc.com/FG170026
). Also, Directive Systems & Engineering offers a 20dBi loop Yagi antenna on their web site http://directivesystems.com/commercial/dse1844ly/
. A 1.8m diameter parabolic dish antenna is going to have a gain of around 28 dBi at 1.69 GHz. If you need that much gain at your location, then your best bet is likely to just use a 1.8m parabolic antenna. If you need a lighter weight parabolic antenna, you might consider one with a grid or metal screen structure instead of a solid metal construction. For a Yagi antenna, you effectively have to double the length of it for every 3dBi of gain added. So if you had a 1.45m long Yagi antenna producing 18 dBi of gain, you would only get 21 dBi of gain out of it by doubling the length to 2.9m. After the Yagi antenna gets long enough, it becomes a problem to keep it straight along its length and maneuver it, if you want to change its position with a motorized mount. The alternative to increasing length is to add more Yagi antennas in an array, which then takes up more space and becomes more challenging with respect to impedance matching to the LNA. Yagi antennas become more and more challenging to build in the 1.69 GHz range as the gain extends beyond around 20dBi. So if you need more gain than that, you should consider finding a way to implement a large parabolic dish antenna. You may want to see if you can find others in your area who have successfully built amateur systems to receive images from the geostationary satellites you are interested in. They could provide useful information on what works in your area as far as antennas for receiving HRIT and LRIT signals. Once you get it all working, please consider posting information to help others interested in building similar systems. Posted images are also of interest.