[RFI] 2 Wire 2701 HG

[Jim Brown]

On Sat, 23 Feb 2008 12:00:42 -0800 (PST), rick darwicki wrote:

>Anyone know a cure or if I can use a regular adaptor with a 
>transformer/diode/cap without killing the modem? 

As long as the electronics wants 5VDC to run, it doesn't much matter 
whether that 5V comes from the el cheapo noise generator or a much 
better one. You could, for example, simply use a 6V filament 
transformer, rectifier, and cap filter to trickle-charge a 6V 
battery and let the battery power any units that wants to see 5V. 
Check the voltage at the battery, and if it's much more than 6V, 
simply add one or two diodes in series that are rated for at least 
2X the load current of the electronics -- an "ON" silicon diode will 
drop about 0.7 volts. 

Most little electronic boxes run on 12 volts, so you can run them 
from a similar setup around a 12 battery, or from the 12-14V power 
supplies that run ham gear. 

BTW -- these float charger -- battery rigs make nice cheap UPS 
backup for this stuff too. 

73,

Jim K9YC