Re: bitx40 displays version, hums, but does not receive #bitx40help #bitx40 #radiuno
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Now, that brings up another idea. Some of the computer/laptop
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power supplies have a 12V line and also a 18/19V line. But it the two power lines are separated and the radio used the 12V line, the amp line could use the higher voltage as suggested by the designer Ashhar Farhan, VU2ESE, and could deliver more power oout. Some printer power supplies have this voltage output. I am not sure they are adequately regulated or noise free enough to use here and are showing up in stores like Goodwill or are available where printers are replaced with new one when they are offering new printers and cartridges for as little as $29.95 and some buy them to get the cartridges. Some voltages are 35V, also. Laptop supplies are often running at 18V, the one mine uses is set at 18V. May not work but it is an idea that bears checking out. Bob ¡ª KK5R -------------------------------------------- On Sun, 12/16/18, Gordon Gibby <ggibby@...> wrote:
Subject: Re: [BITX20] bitx40 displays version, hums, but does not receive #bitx40help #bitx40 #radiuno To: "[email protected]" <[email protected]> Date: Sunday, December 16, 2018, 11:51 PM Laptop switching power supplies are cheap, often available in thrift stores for pennies on the dollar, and can power the PA section. 19 V is common.? ?A cheap switch mode 12 V wall wart can handle the rest.? A seven, eight, or 9 Ahr gell cell is also pretty cheap. $22 at Walmart in the hunting section, as people use them to power deer feeders. ?I have used one pretty successfully with a uBitx, re-charging it with a battery maintainer. ?Just don¡¯t discharge them below 11.9 V or so On Dec 16, 2018, at 23:40, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: As Bob suggests, a simple old school wallwart consisting of a transformer and a rectifier is generally not suitable for powering electronics such as an amateur transceiver. The open circuit voltage will be considerably higher than the voltage under load. And there will be a problem with hum. Even a modern switch mode wall wart of good design probably won't have sufficient power for a uBitx (though a desktop brick style supply might work fine, it can be bigger). But there are good wall warts out there with good voltage regulation and very little noise, well suited for low power electronics such as a radio receiver. ? Jerry, KE7ER On Sun, Dec 16, 2018 at 06:56 PM, Bob Lunsford wrote: In other words, a simple wall wart device delivers that voltage at that current but if the load is decreased, the voltage climbs and could be much hither than the device needing a power supply can survive. Ideally, all our electronic devices will avoid wall warts and a fully regulated power supply, voltage-wise, should be a minimum requirement. Using a wall wart for anything is inviting a castrophe. |
Bob Lunsford