[linux-dvb] [Fwd: Re: Re: Twinhan DST / TS204 and signal qualityquestions]

[Werner Johansson <wj@yodel.net>]

Manu Abraham wrote:
> 		Is there something that we can do to measure the signal level output(using a 
> spectrum analyzer) from the tuner ? Can we check the signal level from the 
> inside stages of the tuner (Output stages of the TSA 5059/ ZARLINK SL 1952 or 
> even a tap from the AGC of the STV0299) ?
I guess most tuners has at least some analog AGC/signal strength output,
but is it relevant information we get there?

> 		What i have seen is that the signal quality/level what you receive on the 
> Twinhan frontend is much lower than that of a conventional STB's. Even with 
> conventional STB's in my region we have a problem with STB's that employ the 
> tuner from LG. We have a low signal on the Hotbird 1,2,3,4,6 satellite. So 
> therefore viewing Hotbird channels on a LG based STB is not a pretty good 
> idea, unless you have a pretty large antenna, whereas you don't have any 
> problems on Nilesat, Arabsat etc. I believe that's one of the reasons why LG 
> STB's don't sell well in this region. The same goes for Samsung LNB's.
I see, what tuner are Twinhan actually using? As they're having their
own ASIC on front of the tuner it seems that they can pretty much use
what they have available?

Also, interesting note about LG, might be an LG tuner on the Twinhans..
:) Could it possible be that the LG tuners are more susceptible to phase
noise than other vendors? This would explain why Samsung LNBs (with
potentially high phase noise) would also be a bad idea? Lots of people
thought that they should be able to reuse their "analog" LNBs when going
for digital, only to find out the horrible phase problems (good signal
strength but crap reception)...

> 		The Twinhan tuners also behave much like the LG tuners when you have a bad 
> signal. Even when i don't have a picture on the Twinhan card, i can watch the 
> same channel on a conventional STB.
My experience exactly, even though I thought I had OK signal to begin
with, but it might be marginal (I get loss of signal even on the STBs
when really heavy rain comes in, but otherwise it's perfect)

> 		It is right that at the driver level there's nothing that can be done, since 
> it can only rectified by the company that manufactures the tuners (not the 
> cards).
That's true... Definitely a hardware limitation..

> Regards,
> Manu
Regards,
Werner