[linux-dvb] Re: Strange problems with two Nova-S cards

[Steffen Beyer <cpunk@reactor.de>]

On Thu, 7 Aug 2003 06:45:02 +0200
Steffen Beyer <cpunk@reactor.de> wrote:

> My current guess is a (still weird) problem with the LNB. If anybody is
> interested, have a look at [1] (german).

After some more investigation I am sure that the LNB is alright. The
problem has got to do with the current the cards need to supply.

Examples:

(remember: V->13V, H->17V)

cards connected to switch->low current:
H - working fine
V - bit errors (at least on one card)

cards connected to LNB->high current for higher voltage:
card0 H, card1 H - working fine
card0 H, card1 V - card0 working, card1 errors
card0 V, card1 H - working fine
card0 V, card1 V - working fine

Moreover I suspect a relationship between reception quality and the
voltage of the 30V line at the tuner module. The card producing worse
results has always the higher voltage on that line, compared to the other
card, and sometimes reaches 32V in the first (switch) scenario, which is
just within the specs (28V-32V).
Yet, I could not figure out how the 30V are generated on the board. Some
kind of step-up DC/DC converter, I guess?

It would be great if anybody could comment on this.

Regards,
-- 
Steffen Beyer <sbeyer@reactor.de>

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