The noise floor of the LM386 possible improvement
January 8, 2010 - 13:19 — ok1rp
Dear folks,
Did somebody tried to improve the noise floor of the LM386 by adding the 10k resistor and 10n capacitor in series between pin 8 and the output pin as it was published in the Oklahoma QRP News Letter and then after by KA4UOS in Sprat nr.79 please?
I am interested in the results...
Thank You for responses in advance.
73 - Petr, OK1RP
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Wilderness Sierra with NESCAF
Hello all,
today arrived my new nine-bander at home... Marine Sierra by Wilderness. Seems to be in great shape incl. all 9 band modules 160-10m so I am going to test it.
Does anybody tried to use NESCAF together with Sierra? I know that Sierra is using the ABX (variable b/w xtal filter 400-1200Hz) so it can be interesting to combine with NESCAF isn't it?
BTW: why Marine Sierra? ...simply because it was used hard by Marine operator before it was sold to me. So this radio spent long time on the sea. :)
73 - Petr, OK1RP
The noise floor of the Sierra Wilderness
Hello,
back to the noise floor... does anybody tried to implement the noise mod into the Sierra radio?
There are two mods which should be able to decreasse the noise of the AF stage of the radios using the LM386 as I announced in preview post.
1. Add the 10k resistor in series with 10n capacitor from pin 8 of the LM386 to his output pin.
2. Reduce the voltage for the LM386 amp from common 8V to 5V only. The LM386 amp works safely from 4.5V and higher voltage increasse the nois only.
Is there anybody for experiments or all of You are on the air...or what happends? :)
73 - Petr, OK1RP