So I have been patiently waiting to get the L-Band Down Converter/LNB that was shown off as part of the Outernet reception kit for RTL-SDR/RasPI. I own a few RTL Dongles and an AirSpy and I can not seem to get Inmarsat/Outernet reception on either of them using an lna4all low noise amplifier and a homemade air gap patch antenna. The lna4all mmic only has about 18db of gain in the L-Band, which is much much less than the LNA you guys sell, or even an amp pulled from an active GPS antenna.
The reason I have been waiting on the L-Band down converter is #1 it looks like a generic down converter which will also handle 2.4ghz and #2 im not sure how much it matters on an AirSpy or highly modified and cooled RTL-RT820T2 based dongle, but moving the L-Band down in to VHF just may help since there seems to be a better noise floor on the receiver at lower frequency’s. So I found the GIT repo for the down converter and decided that I will most likely just send the .brd off to OSHPark and sample the IC’s from LT and AD. I would rather buy a completed board but I am wondering if you guys have scrapped this project, if so why and if not when will it be released?
Thank you in advance
P.S. What happened to the shielded model of your low noise amplifier?
For those of you who may not know what L-Bamd converter I am talking about "I initially saw it on RTL-SDR blog, this is the initial test of a prototype.. The GitHub can be found here, it is a pretty simple design but it is a 4 layer board so its like 30 dollars for PCBs through OSHPark. Im thinking about soldering the mixer on to a QFN to DIP type breakout and then laying that out on a home etched PCB.
@cpt_devine
If you are receiving signal already maybe try pointing the patch antenna very accurately at Inmarsat, patch antennas do have about 7-9db of directional gain so a dead on aim can make a difference. I would first suggest using an Android app called SatelliteAR which makes it easy. If that helps leave the antenna be, if for some reason you get signal fade I would mount the patch on two hobby servos in a pan and tilt configuration, next connect them to your RasPi and use some sat tracking code to make the servos hit Inmarsat dead on all the time. I doubt you need to go past an initial pointing procedure using Sat AR though, since Inmarsat is geo-synchrounous it should stay pretty well in the patch antennas beam without any kind of steering. ::Shamless Plug:: You might also try using something like an lna4all along with the L-Band LNA, if you would like im building very tiny PCBs based on the same chip used in lna4all if your in the US I would be happy to sell you one.
Well I have NO IDEA why but the forum finally suggested a thread that answered my question while I was browsing other topics.
According to this thread the down converters were canned due to price and the leftover proto types are $75 dollars. That makes sense considering the LT5551 mixer is a 15 dollar chip. Is there any way I could just get a PCB, I really want to customize the LO to support the full 3ghz of the LT5551.