[RFI] RF Quiet Laptop for Mobile Console?

doc kd4e at verizon.net
Thu May 18 20:49:55 EDT 2006

> Doc, I have two laptops I use for ham radio purposes: a Mac iBook 900 and an older Dell Latitude 300 (runs Windows 98). Although my Mac is online via a portable satellite internet system (Hughes ne Direcway), both it and the satellite modem can be RF noisy on some HF bands, so I often have to put the Mac to sleep and turn the modem off although my Mac's primary ham radio purpose is to watch for DX spots. The Dell, however is RF quiet (it is never online, so the modem may be disregarded), is used exclusively for HF digital modes (PSK-31, WinLink 2000) and DX logging.
> Both laptops are within 6" of my Kenwood TS-2000 and 18" from my Kenwood TM-261. I hear absolutely no RFI/EMI from either laptop on the 2m rig. My TS-2000 while transmitting does not seem to affect either computer.
> I do not know if newer Dells or Macs generate RFI/EMI. I suppose the use to which the computer will be applied will matter to a significant degree and whether or not it will be connected to a transceiver for digital or control purposes or will be used for non-ham activities (e.g., standard email or web browsing). Given my druthers, I greatly prefer Macs, but Mac ham radio applications are more costly than Windows and there's the occasional EMI factor.
> Both laptops operate directly off 12vdc sources via DC to DC converters (respective DC power supplies; no inverters involved which themselves are RF noisy), plug into cigarette lighter-type plugs.
> 73 de Fred K2FRD

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

Thanks! & 73, doc kd4e  http://bibleseven.com
Ham Links: http://bibleseven.com/hl.html

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