[linux-dvb] Re: TT budget DVB-C 1.0 tuning issues

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Esa Loukkola" <esa@nic.fi>
> I did just this, and wrote a small piece go through different
> combinations for the buf[3] settings. Alas, none of them worked :(.

:(((

> Would playing with the other values in the buf-variable be of any use?

I don't know, but this'd be pretty much poking around in the dark.

> Do you think this data sheet will tell us something which cannot be
> found in the datasheet mentioned in the above email (i.e.
> http://assets.zarlink.com/DS/zarlink_SP5659_MAY_02.pdf), e.g. related
> to the other buf values?

That datasheet only described the PLL chip. However, it does NOT describe
the HF part of the ALPS TDBE2, nor the recommended settings.

I have only found a small description on the ALPS TDBE2, but it clearly
says this tuner has an input range of 47 through 862 MHz, so the frequency
you want to receive is well within its range.

What puzzles me, though, is that the TDBE2 (in contrast to the TDBE1) is
supposed to have a builtin DOWNCONVERTER, which downconverts the signal to
a 5MHz IF (i.e. the signal is in the 1-9MHz frequency band). But it seems
the TT-card does NOT make use of that downconverter and instead grabs the
signal before the downconversion.

To get to the bottom of this, the ALPS datasheet on the TDBE2, which
hopefully contains the pin-out as well as complete programming information,
would be VERY desirable to have. However, I have not found any source of
ALPS datasheets yet :(((

> Does anyone else have experiences with these DVB-C budget cards on low
> frequencies?

As a matter of fact - I do! It just occurred to me that we have two low
frequencies in use here in Germany: S02 and S03, at 113MHz and 121MHz
center frequency, respectively (doh!). Both come in with very good signal
strength (91-92%), though I cannot verify if the reception is actually
error-free, since there are only encrypted services on these channels (but
the service information comes over fine).

So maybe it is not a problem with the driver or hardware after all, but
maybe with your signal? Can you receive those channels with any other
receiver at your place?

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany



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