Octagon SF8008 Supreme

[el bandido]

Here is the best collection of information I have for the symbol rate capabilities in the SF8008 Supreme.

On November 22, 2023, OCTAGON support wrote this about the SF8008 Supreme:
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1. CPU has now got a better and larger heat sink.
2. PCB (Mainboard) has received several changes. (Layout, components and various other than those Components)
3. Tested without problems for months.
4. SUPREME has more interfaces.

Either Octagon knew the advertised symbol rate was a LIE in 2023 or they did not bother to test it. Either way, Octagon advertises the Supreme symbol rate as something that is not possible to achieve. Octagon advertises the Supreme symbol rate range from 100 to 80,000 (Or .1 to 80, Or 100,000 to 80,000,000). In reality, the real symbol rate is 1,000 to 60,000 (or 1 to 60).

Anything below 1.000 symbol rate is not guaranteed. However, Avalink says symbol rates down to 300 may be possible, but may be unstable or with errors. Here is a quote from Avalink when asked about low symbol rate capability in AVL6261C:

For AVL6261C, we support the symbol rate down to 1MSps with performance guaranteed. For low symbol rate, AVL6161C can work till 0.3Msps with performance degraded and long acquisition time.

Here are the advertised specs for AVL6261C from Avalink:
AVL6261C DVB-S/S2/S2X Demodulator
FEATURES:
DVB-S2/S2X
● MODCOD
All normative MODCODs of interactive
service profile
● Both normal (64800 bits) and short (16200
bits) FECFRAME supported
● Normal FECFRAME Symbol rate
QPSK 1-60MSps
8PSK/APSK 1-60MSps
16APSK 1-58MSps
32APSK 1-55MSps
64APSK 1-34MSps
● Short FECFRAME Symbol rate
QPSK 1-56MSps
8PSK/APSK 1-55MSps
16APSK 1-51MSps
32APSK 1-45MSps
● CCM, VCM and ACM supported
● Roll-off factors for pulse shaping: 0.05 to
0.35
DVB-S
● Symbol Rates: 1-60 MSps
● Code Rates: 1/2, 2/3, 3/4, 5/6, 7/8

Even the high symbol rate of 60 is not available in all modulation modes. Octagon is advertising a high symbol rate of 80, which is ridiculous as this is 33% more than the specs of Avalink.

There have been several attempts by Octagon to fix the low symbol rate where it is useful, but all of the attempts have either failed, broken something else in the process, or Both.For further aggravation, Ghidra shows an Open Source License for the AVL6261C in the Octagon image. If you have an Open Source License, then you are supposed to provide the sources the driver was made with which Octagon refuses to do.

The same driver, AVl6261C or AVL626X1 is used in the Edision receivers. Both Edision and Avalink have made the sources available where anyone may build the demodulator or tuner driver for the Edision 4K receivers. Octagon could do the same thing and release their source code, but they refuse to do this.

At some point in a future time, Octagon may release a driver that performs somewhat better on symbol rates that are below 1,000. But a symbol rate of around 500 is the lowest we could get the Edision receivers to function, and I expect the same for the Supreme. Just remember, the symbol rates for the Supreme are really 1,000 to 60,000, and NOT the 100 to 80,000 Octagon advertises. Any symbol rate below 1,000 may not work and/or may be unstable in the Octagon SF8008 Supreme.

[el bandido]

Having a signal below lock helps when aligning, adjusting or moving a satellite dish. IMO, Octagon should use what little influence they have with enigma2 image groups and try to get the signal below feature added to them. Georgia played in the women's college softball regionals this evening, and I decided I wanted to watch that game.

The 1.2 ku meter dish was giving about 12.6db on a 16apsk transponder with a 4/5 fec. This is really a marginal signal for glitch free viewing for a transponder such as this, so I moved the 2.4 meter ku dish from 87w to 103w to make viewing the game enjoyable. i installed the TinySA spectrum analyzer into the lnb feed to make dish alignment easier.

The dish pole is marked for 103w, which makes it a bit easier to find the correct location, but both lnb skew and dish alignment are pretty critical on a Prodelin 2.4 meter dish. The TinySa spectrum analyzer usually makes this job easier because you can see the transponders on a satellite before they are strong enough to be seen on the fta receiver.

Having signal below lock really helped with this move. The transponder and its 7 channels had already been scanned with the 1.2 meter dish, so the Signal Meter Android app was opened and a signal was set on the target transponder. The signal meter kept repeating the word zero audibly while the dish was being moved from 87 to 103w. Then about the same time the TinySa started showing some weak transponders for 103, the Signal meter said the word 'Two". Bingo!

A 16apsk transponder with a fec of 4/5 is not going to lock until it has a signal around 11 db(snr). So it sort of shocked me to hear the Signal Meter app say the word "two". Signal on the 2.4 meter dish peaked out a bit over 15db which guaranteed a decent signal for the softball game.

Going to the trouble of shutting everything down, installing the TinySA spectrum analyzer, then powering everything up was a waste of time. The SF8008 Supreme demodulator/tuner combination is sensitive enough to where you do not need to install the spectrum analyzer.

Trying to move a 2.4 meter ku dish like this where you are not going to get a signal on the target till 11db would be very difficult. Having signal shown below lock is Very Valuable in a situation like this. Hopefully Octagon will realize this and try to do something about getting it added to enigma2 images.


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[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]