Reception on 15w of some transponders

[picoman]

Re: Reception on 15w of some transponders

I've just checked and all the channels that the ET8000 does not tune have low SR (less than around 4050).
eg on 10°E
TV Zimbo SR 2480
ORTC SR 3255
Rasheed SR 3700

(all OK on the VU).

However, it does tune some channels with low SR
eg
Service-1 10985H 3/4 SR 3124
and
CN Mena 11585V 5/6 SR 3330

So I do not know what is going on there.

its probably the same the other way round, (higher) s/r

Intelsat 907 @ 27.5° West
11495 V DVB-S2/QPSK MPEG-4 44100 9/10 (bbc channels)

vu box no problem, spiderbox7000 no chance.

Yes, but the spiderbox tuner is probably not designed for the high SR.

The ET tuner "should" be designed for low SR and indeed it does work on some but not others.
(Incidently it does work fine at 44100 too).

[sasho123]

Re: Reception on 15w of some transponders

you can try to update your box Image If It Is too old

[picoman]

Re: Reception on 15w of some transponders

I'm using the latest OpenPli (and I believe the most recent drivers too - 3.17.3).
However, as a test I've just tried the latest OpenVix image and there is exactly the same problem so I have reverted to my backup of OpenPli.

[picoman]

Re: Reception on 15w of some transponders

I've fixed the problem with tuning low SR transponders with my ET8000.

What I did was change the frequencies down, between 2 and 4MHz and rescanned. The missing channels then came in with a strong signal.
ie instead of using the correct frequency of 11611H I used 11609H
and
instead of using the correct frequency of 10997V I used 10994V
etc.

It must be strange bug with this box/tuner/low SR channels.

Anyway, if any one else is struggling to tune low SR channels try altering the frequency a little.

[digicon]

Re: Reception on 15w of some transponders

Its called 'LNB Frequency Drift' if your receiver had some form of blind scan option it would automatically pick those frequencies up, similar to how a closed source receiver does.

If you changed the LNB on your dish to a different type-brand then you would probably see the frequency's change again

[picoman]

Re: Reception on 15w of some transponders

I initially tried to install "Blindscan" on the ET8000. Unfortunately it does not work (even though the tuner type is the same as my Vu+Duo2). Xtrend do not have the correct drivers.
That is why I used the manual method of altering the frequency.

Is the "no tune" problem caused by 'LNB Frequency Drift' a fault of the LNB not maintaining the correct frequency, or the STB not allowing/compensating for this "drift"?

[digicon]

Re: Reception on 15w of some transponders

Unsure on the No tune as this is mainly regarded as No signal at all although as you say it could be due to frequency drift as well and here is why a PLL LNB may help akthough i am yet to find an all round sensitive PLL KU-LNB for fringe reception or any that are as good as the Inverto Black Ultra

Taken from satsig:

LNB Frequency stability

All LNBs used for satellite TV reception use dielectric resonator stabilised local oscillators.  The DRO is just a pellet of material which resonates at the required frequency.    Compared with quartz crystal a DRO is relatively unstable with temperature and frequency accuracies may be +/- 250 kHz to as much as +/- 2 MHz at Ku band.  This variation includes both the initial value plus variations of temperature over the full extremes of the operating range. Fortunately most TV carriers are quite wide bandwidth (like 27 MHz) so even with 2 MHz error the indoor receiver will successfully tune the carrier and capture it within the automatic frequency control capture range.
If you want the LNB for the reception of narrow carriers, say 50 kHz wide, you have a problem since the indoor receiver may not find the carrier at all or may even find the wrong one.   In which case you need a rather clever receiver that will sweep slowly over a range like +/- 2 MHz searching for the carrier and trying to recognise it before locking on to it.  Alternatively it is possible to buy Phase Lock Loop LNBs which have far better frequency accuracy.  Such PLL LNBs have in internal crystal oscillator or rely on an external 10 MHz reference signal sent up the cable by the indoor receiver.  PLL LNBs are more expensive. The benefit of using an external reference PLL LNB is that the indoor reference oscillator is easier to maintain at a stable constant temperature. Ka band LNBs operate at such high frequency that they can need phase look loop frequency control unless the wanted carriers are very large bamdwidth.  An internal PLL uses a crystal oscillator in the LNB.  An external reference PLL uses a 10 MHz reference supply from the customer's indoor modem or receiver.

[picoman]

Re: Reception on 15w of some transponders

Well yes, my "No Tune" was due to "No signal".

Some useful info in the satsig quote. Thanks.

Do the transponders using low SR naturally become narrow bandwidth?

I've got a few different LNBs. When the weather is a bit better I'll swop them over.
However, it may be that it is the colder temperatures that is causing the problem too?