[Ronja] Vacuum tube in Ronja preamplifier

J.D. Bakker jdb at lartmaker.nl
Mon Oct 15 14:02:17 BST 2007

>  >Fibre optic system doesn't have ambient light from the sun with 
>the associated
>>strong noise source.
>Indeed, but if the *sun* dominates, then receiver noise factor is not a big
>deal ?

Sun noise doesn't necessarily dominate, see


ie: daytime sun-induced shot noise is equivalent to ~ -43dBm.

>Then only fix is filtering / optical screening to lower sun optical noise,
>is that not so?

That would be a good plan. I still hope to find the time to 
experiment with gel filters such as are used by theater lightning 

Point remains that the current front-end is noisier and less 
sensitive than necessary; IMHO a change of architecture (active 
transimpedance amp versus the resistor that's used now) helps more 
that going for a hard-to-get vacuum tube would.

LART. 250 MIPS under one Watt. Free hardware design files.

More information about the Ronja mailing list