Manhattan Noise Bridge
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For some things that I test on a receiver, I find the following to be
of great use around the lab.? It uses the fact that a zener diode will generate a lot of random noise.? Let's not nit the pink vs gaussian vs exponential vs white vs .... types of noise. 1.? Use it at the build of each stage in a receiver, if you start with the audio amp first as in the series of videos I'm doing. 2.? Use it after a build or even for working rigs to test the IF filter.? Requires an audio analysis computer program that shows a spectrum plot.? I'm currently looking for an ARM based SBC program since most non-free software binaries run only on Intel/AMD base computers.? Open source would be great. 3.? Irritate the neighbors. Attached: 0084.jpg? original prototype using on two stages on PCB done toner transfer Screenshot...? showing Manhattan layout drawn by C program I wrote ?????????????? I will come back and change the call sign.? :-) Schematic lost in the dark caves of large SSDs and to be recreated at some later date.? But you can reverse engineer the layout to a schematic.? You've been there and done that many times before. BOM: R1,R3,R5? 1.2K? 1/4W resistors? (not too critical) R7??????? 680ohms? 1/4W resistor?? (drives the final stage harder) C1,C2,C3,C4? 10nF mono or disc caps? (.01uF if you prefer labeled 104) D1??????? 6.8V?? 1/2W zener diode Q1,Q2,Q3? 2N2222, 2N3904 or 2N4401 NPN transistors? (just about anything) The part values are not critical.? You can use what you have in the parts depot in the closet and it's more fun to experiment. I think I got everything.? Exercise for the student(s). This critter will be used pretty soon in the ongoing videos and there after many times. FYI -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA |
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Just to add a little more noise to the conversation (see what I did there?) I built something like that based on an old design by N0SS.??
https://web.archive.org/web/20050331110118/http://www.n0ss.net:80/noise_source.pdf
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It was my first attempt at toner transfer etching and it came out good enough to work.? If anybody cares you can read my write up at /g/HBTE/topic/28926106#msg323
In case it isn't obvious to every single person reading this, I barely know what I am doing and I am trying to figuring it out as I go.? Listen to Chuck, not me.
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my meager attempt...??
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¡ì97.313?? Transmitter power standards.
(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications. |
