Re: [Elecraft] RF Hash from IBM Laptop
BE VERY CAREFUL DOING THIS! This advice is specific to a single product form one manufacturer. Each laptop manufacturer has different battery maintenance circuitry, and they operate off different voltages, usually NOT 13.8V! Input voltages tend to vary between 12 v and 30 v depending on manufacturer. As an example, Apple PowerBooks and iBooks need about 25 volts. Applying 20V to a 12V input WILL cause undesired effects. Applying 12V to an 18V input MAY cause undesired effects. Also, be sure that any power adapter you use will provide enough power to run the laptop. Laptop power supplies started out at about 20 watts many years ago, and generally run around 45-65 watts these days. I would STRONGLY advise that anyone wanting to run their laptop from a 12V battery source purchase a commercial power adapter for their laptop. These are available from many sources, including your local neighborhood computer store. On Aug 29, 2004, at 11:14 AM, Bob Tellefsen wrote: Hi don I have two laptops here, and both can be run from an external battery source. HOWEVER, I need to run them through a small inverter to bring the voltage up to around 13.8v. I checked this with my variable voltage bench power supply to find out where the laptop switched from external power to internal. It is usually above normal battery voltage by 1-2 volts, hence the small inverter. I built the one from Sam Ulbing, N4UAU. It was written up in QST as "My All-Purpose Voltage Booster". He sells the kit for a very reasonable price. You can find him on the web under his call. I used mine on Field Day, and it was extremely quiet. Not a trace of hash anywhere. A side benefit in running on batteries in the field is that the converter is regulated. As the input voltage drops, the output stays pretty near constant. This would not be a problem in the shack with a fixed supply. I suggest you check your laptop using a variable voltage power supply and find out how low you can go before it switches over to the internal battery. Good luck and 73 Bob N6WG - Jack Brindle, WA4FIB - ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] RF Hash from IBM Laptop
Sam can be reached at [EMAIL PROTECTED] or you can find him any morning at 0700 Eastern on 7050 - Waterway CW Net. Paul K1PT - Original Message - From: "Ron D'Eau Claire" <[EMAIL PROTECTED]> To: Sent: Sunday, August 29, 2004 2:59 PM Subject: RE: [Elecraft] RF Hash from IBM Laptop Vivisimo.com usually works a lot better for me as a search engine. Plugged it in there and it came back with N4UAU's home page which is "down" and this link straight to details of the power supply: http://tinyurl.com/5wjrh Ron AC7AC -Original Message- "Bob Tellefsen" <[EMAIL PROTECTED]> writes: > > I built the one from Sam Ulbing, N4UAU. It was written up in QST as > "My All-Purpose Voltage Booster". He sells the kit for a very > reasonable price. You can find him on the web under his call. > I've not having any luck finding Sam's site with Google, nor via the QRZ reference, and it's been that way for at least a couple of weeks. I have a couple of his kits, and they work well. 73, doug ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] RF Hash from IBM Laptop
Well, DANG! If I'd finish a message before hitting SEND it'd help. Since N4UAU's site is down, you can get the schematic and lots of info (a LOT of info if you speak French) here: http://tinyurl.com/5f943 It's the complete construction info in French but the schematic is in English. Also, other references say the circuit was published in QST in 1997. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] RF Hash from IBM Laptop
Vivisimo.com usually works a lot better for me as a search engine. Plugged it in there and it came back with N4UAU's home page which is "down" and this link straight to details of the power supply: http://tinyurl.com/5wjrh Ron AC7AC -Original Message- "Bob Tellefsen" <[EMAIL PROTECTED]> writes: > > I built the one from Sam Ulbing, N4UAU. It was written up in QST as > "My All-Purpose Voltage Booster". He sells the kit for a very > reasonable price. You can find him on the web under his call. > I've not having any luck finding Sam's site with Google, nor via the QRZ reference, and it's been that way for at least a couple of weeks. I have a couple of his kits, and they work well. 73, doug ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] RF Hash from IBM Laptop
"Bob Tellefsen" <[EMAIL PROTECTED]> writes: > > I built the one from Sam Ulbing, N4UAU. It was written up in QST > as "My All-Purpose Voltage Booster". He sells the kit for a very > reasonable price. You can find him on the web under his call. > I've not having any luck finding Sam's site with Google, nor via the QRZ reference, and it's been that way for at least a couple of weeks. I have a couple of his kits, and they work well. 73, doug ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] RF Hash from IBM Laptop
Hi don I have two laptops here, and both can be run from an external battery source. HOWEVER, I need to run them through a small inverter to bring the voltage up to around 13.8v. I checked this with my variable voltage bench power supply to find out where the laptop switched from external power to internal. It is usually above normal battery voltage by 1-2 volts, hence the small inverter. I built the one from Sam Ulbing, N4UAU. It was written up in QST as "My All-Purpose Voltage Booster". He sells the kit for a very reasonable price. You can find him on the web under his call. I used mine on Field Day, and it was extremely quiet. Not a trace of hash anywhere. A side benefit in running on batteries in the field is that the converter is regulated. As the input voltage drops, the output stays pretty near constant. This would not be a problem in the shack with a fixed supply. I suggest you check your laptop using a variable voltage power supply and find out how low you can go before it switches over to the internal battery. Good luck and 73 Bob N6WG ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] RF Hash from IBM Laptop
Wondering if any of the Elecraft gang would happen to know if I can safely power my IBM 380D laptop from a 13.8 VDC power supply without causing any harm to the laptop. I use this laptop exclusively for my logging. The factory wall supply is like most laptop supply's, it's a switching supply and it creates lots of RF hash that I can hear in the receiver. 73, Don WA9TGT / Donnie Garrett / Muncie, IN ARCI #6447, ARS #1717, AmQRP, ECI-QRP #001 K2 #4003, K2 #3186, K1 #1806, K1 #0416, SW-30+, DSW II - 40 LDG Z-11 Auto Tuner, 102' CF Zepp fed with 300 Ohm Line ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com