There is another way to slow down and thus reduce the sound level from a fan (or blower). Connect a resistor and electrolytic capacitor in parallel, then connect that combination in series with the fan. When power is first turned on, the fan sees full voltage to get it started. Then, the fan voltage is gradually reduced to a lower level to keep it running more quietly. The value of the resistor controls the long-term fan voltage and thus the noise level. The value of the capacitor controls how long the fan receives higher starting voltage. Make sure the resistor's power rating is sufficient for the long-term run current.
Turning power off and on too quickly can outsmart that simple circuit. A more complex circuit could avoid that shortcoming if needed. The simple circuit has worked well enough in an A/V switcher I designed and built a couple of decades ago.
HTH
--
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)
Yes, but I often get asked "What do you do with the Raspberry Pi?" (as if there's just one!) so having the Web page shows at least a few of the things which interested me. I'm also following Es'hail 2, but dish space here is limited, so likely it will be the Web SDR (at Goonhilly, England) for me. It's interesting to see people tracking the Doppler - at least during the transition. There's a lot on Twitter, with some folks thinking of using the Raspberry Pi as a basis for transmitting.
What matters mostly for your ADS-B antenna is height - how clear of local obstructions you can get. As you note, both ADS-B and AIS decoding are ideal for the Raspberry Pi.
You do sound to have similar interests (although off-topic here), so you may like to join the PlanePlotter and ShipPlotter groups, and perhaps make a contribution.
to make a stable reference for my LNB, I received a bit different LNB:
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and according to my calculations I need a 24 MHz reference,. So this board makes 24 MHz locked to a Rubidium ebay 10 MHz reference, it uses a LMX2332 also from ebay.
Wrote some software for that LMX2332:
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Anyways I need some better weather to do some test with that modified LNB, will probably wait until Es'Hail 2 is at its final position end of the month.
Think I can get SSB that way, and also ATV.
As far as transmission goes, as this project got delayed and delayed... I do have to stay on topic designed an ATV transmitter modulator:
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and bought a linear amplifier that should also work in that band:
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but as things were delayed it is somewhere deep hidden in some cabinet... We will see what happens. I read
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every now and then...
For ATV transmit it seems I need a bigger dish, bit of a problem with wind, for example we are in a storm now.. force 7.
Yes, exactly, and for AIS (ships) when testing at home I am screened on the sea-side by some high buildings. leaves me only the traffic on the land side (canal).
I have a project going with my Hubsan 501S drone, powered via a thin coax, with a slim-jim hanging as AIS antenna, that convert the AIS to an other band and then a DVB-T stick in the raspi.
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Can keep it in the air indefinitely...:
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would make a nice high antenna...
Unfortunately the government decided to declare where I live a no-fly zone, am close to a mil airport. but there is new legislation coming, will see what it gives,
I will do some reading on those groups,. I have many interests, and an electronics background and normally hang out in sci.electronics.design, sometimes under aliases...
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