[VHFcontesting] Inverter Advice

Lee Scott - AA1YN aa1yn at aa1yn.com
Wed Sep 3 20:57:05 EDT 2003


I built a DC to DC converter using the LT1070 and parts from an old PC 
switching power supply.  My laptop is an Acer and uses 20vdc.  The LT1070 
provided plenty of power to run it at full tilt with the CD-ROM running 
continuously while recharging the laptop battery.  I used the same circuit 
that Linear Technologies provides for the boost circuit.  Use the toroid 
core to wind a new inductor for the boost circuit. Also use the diodes from 
the power supply as it is on a heat sink and is a high freq diode.  The 
diode gets hotter than the LT1070.  On both the input and output, put a 
common mode filter to keep any of the 30kc noise off of your battery. I 
also used the old supply case to hold the thing. Cost me a total of $11.00 
to build. I don't even know how much inductance there is on the toroid core 
but I put about 25 turns of #14 wire on the 1 1/4 inch core.  The LT1070 
provides the regulation so you don't need another one.

Had absolutely no problems with it during the 10g and up contest.

Lee Scott - AA1YN
Home of the VHF & Up Register http://www.aa1yn.com/vhf
Hooksett, NH
FN43gc52




More information about the VHFcontesting mailing list