Well, on to more interesting things… Can we hear Ku band with a raw feed horn in the Seattle area? Hmmm. I don’t have my Standard and Universal Ku band feedhorns yet… What about the feed horn that’s in this little 18 inch RV antenna?
So let me explain the picture… In the background is a Winegard 18in RV antenna. I took the feedhorn and clamped it with my Velleman circuit board clamp and then fed the RG-6 coax to (a shameful mess of) adapters that convert F to N and N to SMA. And the SMA connector goes to the RF+DC side of a Mini-circuits 15542 bias tee, which I supply with 12 volts (all of this is not shown in the photo). Then the RF side of the bias tee connects to the SDRx, which you can see is plugged-into my Linux Skywave laptop. The feedhorn is aimed towards Galaxy 28.
So what do I get? Well, take a look at this picture first.
Interesting to say the least, but not what I had expected. The whole lower L-Band from about 900 MHz to about 1750 MHz has complex OFDM-like carriers on it, spaced about every 2.4MHz.
OK … what’s going on here? The first thing to realize is that there is actually a third kind of Ku band LNB that is used in North America. Shame on you Wikipedia, you forgot all about this. It turns out that the Winegard antenna is made for DirecTv, which uses circular polarization and not linear polarization. It uses a different LO, aparently 10,600 MHz, if I have figured it out right.
I’m still not sure what I’m really looking at. I’m still learning more and these experiments are helping me uncover more about satellite communications. Maybe some of you guys with the years of satellite experience here can throw a few hints?
I’m still waiting for the FTA Standard and Universal LNBs I bought… and eventually the DC3.