[linux-dvb] Preliminary support of Hauppauge Nova-T 500 Dual (take 2)

Patrick Boettcher patrick.boettcher at desy.de
Wed Sep 20 11:55:02 CEST 2006


Hi,

On Wed, 20 Sep 2006, Jose Alberto Reguero wrote:
> I made a experiment, and take the agc params from dib3000p_mt2060_agc_config 
> from  dibusb-common.c line 170 and put in bristol_dib3000p_mt2060_agc_config 
> from dib0700_devices.c line 26 except ".setup" and I have much beter results. 
> I can tune to this frquency with LNA off and with LNA on with good results 
> (similar ber, a little better with LNA on).

Uh la la. Never ever do that. AGC settings are (most of the time) 
determined by a process of calibration (checking for sensitivity, high 
power, backoff in different adjacent channel scenarios (Nordig, MBRAI)). 
The settings which are there are optimized for the nova-t 500 (knowing 
that there is an LNA).

If you now use different settings, they may work very good for you, but 
most likely very bad for others (with other reception conditions). The AGC 
calibration is always a compromise to achieve usable reception for 
everyone.

That reception is working with LNA on and off is, btw, no indicator. The 
LNA should be used, if you live in an area, where signal are very low. 
That the Nova-T 500 has only one LNA for both channels is a bit unlucky, 
that's why it is now switchable with a module parameter.

So once again: unless one is not 100% sure of what he/she is doing, DO NOT 
TOUCH AGC parameters. Otherwise it will be quite impossible to support 
people reporting bad reception quality.

best regards,
Patrick.

--
  Mail: patrick.boettcher at desy.de
  WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/



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