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Re: Would this P/S work?
even LT1083CP can well be managed upto 7amps of load. being a low drop regulator ?one can manage a trafo with 24V secondary ? regards Sarma ? On Wed, Oct 18, 2017 at 8:55 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: 5w out powered from an LM317 sounds fine. |
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Re: Would this P/S work?
5w out powered from an LM317 sounds fine.
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And yes, the current limiting would be very handy. 20w out of the bitx40 with the irf510 at 24v would not work quite so well. On Wed, Oct 18, 2017 at 08:04 am, David McGough wrote: Output power after the LP filter is about 5W (+/-). |
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Re: Would this P/S work?
An LM317 is a "bullet-proof" choice for powering an IRF-510, in my
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experience. I use this solution for beacon transmitters and they tolerate about anything (except lightning!). Since the LM317 provides fast-acting current limiting, this has saved my IRF-510 on many occasions when various antenna system failures occurred. I power the LM317's from surplus HP deskjet switchers. Works GREAT and been on-line 24/7 for years now! The CW note is very clean, no detectable clicks, etc., with very low spurious noise--there are several very active hams on 10M within line-of-sight to the beacon antenna and less than 1 mile away! Here are some links: Here is a schematic of the beacon. It's simple and brute-force. Note that the output low-pass filter isn't shown. This schematic also pre-dates a better output matching solution. Like I mentioned, it has been on-line continuously for years now, through antenna/feedline failures and all; sometimes with very bad SWR for days at the time! Output power after the LP filter is about 5W (+/-). 73, David KB4FXC On Wed, 18 Oct 2017, Gordon Gibby wrote:
?I think the main board is about 100-150 ma? |
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Re: Would this P/S work?
Yes, around 150ma.
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0.5v sounds high, perhaps more like 0.1v rms for the microphone input? Laptop supplies are usually spec'd conservatively and are well designed.? Lenovo/Dell/Asus/Acer/HP/Samsung/Apple can't afford the headlines. A large cap will help on voice peaks if performance on current transients is marginal.? RF filtering using toroids and caps could be used to cut the noise if necessary, on both dc out and ac in cords. ? And maybe enclose it in something RF tight, though watch out for overheating. But I think some folks are using laptop supplies on the bitx40 without any such measures. On Wed, Oct 18, 2017 at 07:22 am, Gordon Gibby wrote:
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Re: Would this P/S work?
Gordon Gibby
¿ªÔÆÌåÓý?I think the main board is about 100-150 ma?
Droppng 12V (from 24--> 12) would be about 1.2 - 2 watts, could be done with a small heatsink.? ?
I don't yet know about the noiselevel of laptop supplies.? ?While rated often for 2A, some of mine get pretty warm when chargeing AND running a dead laptop;? ?the one on my Lenova is rated 20V @ 2.5 A and for medium dutycycle 50% it is probaby fine.? ?Since
they are produced in such large quantity, they are quite cheap.? ? I have one running an LDG auto tuner right now (a 12V laptop supply).? ??
My next project is to build an itty bitty 10X preamp for the mic input; I've read the bitx needs 0.5V? --- holy cow!!? ?Had to turn a signalink nearly halfway up, farther than I've ever had to turn one, and screaming into a powered mic was necessry.....that
should be easy to fix with a tiny 1-transistor preamp.? ? I'm using this for psk31 and WINLINK.? ?Hit four winlink gateways the other evening.? ?Cool rig.
From: [email protected] <[email protected]> on behalf of Jerry Gaffke via Groups.Io <jgaffke@...>
Sent: Wednesday, October 18, 2017 9:50 AM To: [email protected] Subject: Re: [BITX20] Would this P/S work? ?
However, something like an LM317 with heatsink might be about right for powering
the main bitx40 board from the same 19-24v. that you feed the irf510 with. Then you could get by with a single old laptop power supply if it's not too noisy. On Wed, Oct 18, 2017 at 06:44 am, Jerry Gaffke wrote: Powering the BItx40 at 24v will require on the order of 50w, |
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Re: Would this P/S work?
However, something like an LM317 with heatsink might be about right for powering
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the main bitx40 board from the same 19-24v. that you feed the irf510 with. Then you could get by with a single old laptop power supply if it's not too noisy. On Wed, Oct 18, 2017 at 06:44 am, Jerry Gaffke wrote:
Powering the BItx40 at 24v will require on the order of 50w, |
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Re: Would this P/S work?
Powering the BItx40 at 24v will require on the order of 50w,
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A load like that would turn those ebay LM317 regulators into smoking ash. That stuff gets spec'd as aggressively as they can sneak by with. And then a little bit more. On Wed, Oct 18, 2017 at 03:53 am, Thomas Sharka wrote: The LM317 version of the DC converter would be my choice. You'd need a 15-24 volt AC power transformer for it's input. |
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Re: Would this P/S work?
Gordon Gibby
¿ªÔÆÌåÓýHave you considered trying? laptop powr supply?? ? I found a 19V one in? a thrift shop for $5 and it seems to work so far; I added a 50 microfarad cap and a 0.01 at the output;??
here is one from walmart at 24VDC? for $10
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From: [email protected] <[email protected]> on behalf of Dave <k4em@...>
Sent: Wednesday, October 18, 2017 6:33 AM To: [email protected] Subject: [BITX20] Would this P/S work? ?
for powering the bitX40? final to 24v? Just add the appropriate power transformer, fuse, etc, seems reasonable.?
Would a LAB adjustable power supply be a good choice for powering the bitX40? This one is linear not switching. Dave k4em |
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Re: Would this P/S work?
The LM317 version of the DC converter would be my choice. You'd need a 15-24 volt AC power transformer for it's input. The Lab supply would be a bit of overkill, but if you're building circuits, it would be an essential part of your workbench. You could get by with a 12 volt 2 or 3 amp regulated supply otherwise. ? Sent from Yahoo Mail. On Wednesday, October 18, 2017 6:34 AM, Dave <k4em@...> wrote: for powering the bitX40? final to 24v? Just add the appropriate power transformer, fuse, etc, seems reasonable.? Would a LAB adjustable power supply be a good choice for powering the bitX40? This one is linear not switching. Dave k4em |
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Re: Temp Monitoring
Jack Purdum
Too big. Jack, W8TEE From: AA9GG <paul.aa9gg@...> To: [email protected] Sent: Tuesday, October 17, 2017 10:33 PM Subject: Re: [BITX20] Temp Monitoring This is a pcb module we use at work for the DS18B2....BTW, I have this working in my BITx40v3
-- Paul Mateer, AA9GG Elan Engineering Corp. NAQCC 3123, SKCC 4628 |
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Re: New file uploaded to [email protected]
After adding in new Lib.? :? #include <Encoder.h>? ? ? ? ? // Upload OK and rotary appears to be way better: if you don't upload the new lib. you will get a compile error related to the Encoder.h (don't forget:? ?MorseCode.h) Thanks again Jack, Larry? WA9DOH On Tue, Oct 17, 2017 at 3:36 PM, [email protected] Notification <[email protected]> wrote:
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New file uploaded to [email protected]
[email protected] Notification
Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group. File: B40SoftwareRel0108.ino Uploaded By: jjpurdum Description: You can access this file at the URL: Cheers, |
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New file uploaded to [email protected]
[email protected] Notification
Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group. File: B40SoftwareRel0108.ino Uploaded By: jjpurdum Description: You can access this file at the URL: Cheers, |
AA9GG
