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Re: [RFI] RF Quiet Laptop for Mobile Console?

To: RFI List <rfi@contesting.com>
Subject: Re: [RFI] RF Quiet Laptop for Mobile Console?
From: Fred Stevens K2FRD <k2frd@mac.com>
Date: Thu, 18 May 2006 18:07:37 -0700
List-post: <mailto:rfi@contesting.com>
At 7:49 PM -0500 5/18/06, doc wrote:
>Thank you for that report Fred.
>You said you used a dc-dc converter, so the native
>voltage for the Dell is something other than 12vdc?
>Perhaps 16 or 19 or 24 vdc or something?
>Some of the dc-dc converters can be rf noisy as well.
>Are you using the Dell dc-dc adapter or some other

The Dell works off 20vdc while I *think* my Mac iBook is a nominal 16v. I use 
the Dell dc-dc adaptor/converter made specifically by Dell for Dell Latitudes; 
found it on eBay for about $15. I suppose it would work on other Dell laptops, 
but wouldn't want to bet the farm on it; probably differing computer power 
connectors although there may be different voltages as well. The Mac's DC power 
supply is made specifically for Apple laptops, but I know it will not 
physically fit all Mac laptops (i.e., older laptops); they also have differing 
plugs, but I am not certain about the voltage compatibility; the Apple 
"Universal Car/Air Adaptor" puts out 15 to 24 vdc according to its label. No 
noise from either UNLESS my battery bank from which I power all my computer and 
radio gear drops below certain voltages, usually around 12.3 vdc when the 
converter/adaptors start cycling on/off in which instance there will be S9+ 
"clicks" on my HF radios. I have considered purchasing a "battery extend
 er" (actually a voltage regulator) which would keep the battery voltage up 
above the cutoff voltages, but just haven't done it (Oct 05 QST had a product 
review of such a 20-amp extender, but the manufacturer received so many 
requests/orders as a result of the article that he quit making them; there was 
also a QST article on homebrewing such an extender several years ago, but I 
happened to give away that issue in a fit of generosity). Commercial battery 
extenders with current capacity high enough (20+ amps) are available for about 
100 bucks and up.

73 de Fred Stevens K2FRD, VO2FS
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