Today, I was on the 117W sat to look at a signal posted in another thread, and while there I came across a signal at 11771 H ? sr ?. I've seen signals like this before, but didn't know what they were, and couldn't lock them. The constellation diagram from Crazyscan looks like a combination of 2 phases of BPSK, and sometimes full QPSK, and maybe a zero in the middle. Ie starts like shown below:
![Image5.jpg]()
Then looking like QPSK:
![BPSK-4.jpg]()
I didn't think that there was any of our receivers that could lock these modes, but then while looking through the specs of some S2x receivers I noticed a mode called 2_4_2_APSK. I thought that perhaps this was what I was seeing, ie 2_4_2 ?=? (BPSK1)-(QPSK)-(BPSK2). I guess if it was, I would have been able to lock it with one of the S2x receivers, but I am curious re what 2_4_2_APSK actually is? I tried to google it, but all I came up with was links to S2x receiver specs, but no explanation of what that mode inferred. My 5520se lists this 2_4_2_APSK mode, so I tried it, however while it showed the same constellation, it did not lock, so apparently this is not what this mode is. I tried the 6903x, and same thing. I think that a couple years ago I tried one of the SDR programs that was capable of BSK, and couldn't lock there either although I may be remembering wrong on that.
Anyway, does anyone know what mode this 11771H transponder is, and is there any receiver capable of locking it. And also, what is this 2_4_2_APSK mode??
Then looking like QPSK:
I didn't think that there was any of our receivers that could lock these modes, but then while looking through the specs of some S2x receivers I noticed a mode called 2_4_2_APSK. I thought that perhaps this was what I was seeing, ie 2_4_2 ?=? (BPSK1)-(QPSK)-(BPSK2). I guess if it was, I would have been able to lock it with one of the S2x receivers, but I am curious re what 2_4_2_APSK actually is? I tried to google it, but all I came up with was links to S2x receiver specs, but no explanation of what that mode inferred. My 5520se lists this 2_4_2_APSK mode, so I tried it, however while it showed the same constellation, it did not lock, so apparently this is not what this mode is. I tried the 6903x, and same thing. I think that a couple years ago I tried one of the SDR programs that was capable of BSK, and couldn't lock there either although I may be remembering wrong on that.
Anyway, does anyone know what mode this 11771H transponder is, and is there any receiver capable of locking it. And also, what is this 2_4_2_APSK mode??
Category: Computer and USB Satellite Receivers and Recording