wrote:
I am relatively new to ham radio. I am wanting to build a base station
in my bonus room and use some mobile radios up there.

Is it feasible to build my own power supply? I know one radio requires
13.8 volts and a minimum of 12 amps. I would like to use more than one
radio though.

What about buying one of those cheap emergency jump start pwer cells
you can keep in your car. Could I just use one of those and keep it
plugged into the wall charging at all times?

I like the idea of building one but not sure if it would cost more that
way or not. What would I need to build one besides a transformer and
rectifier?


Some people use a car battery with trickle charger on it all the time.
But there are issues with caustic vapor in the shack.

If you build a power supply, put your primary attention on over-voltage
protection. If something goes wrong, a semiconductor shorts and puts
WAY too much voltage on your raido. The semiconductor spec issues
that are CRITICAL in this type of application are the least understood
by newbies...and engineers too. If it's a linear supply, you'll need
SEVERAL TIMES as many
pass transistors (properly current shared) than you'd think from the
dissipation ratings. Do some research on secondary breakdown or SOA.

Evaluate the finished product with transient loads as well as fixed
loads in various stages of current limit. Make sure you have enough
oscilloscope bandwidth to see those 100MHz oscillations and big
transient spikes.

"Well, I saved $50 on a power supply and blew up two $1000 radios."
Don't let this be you. Keep an eye out for a used Astron...and test it
thoroughly before you hook it to your radio. Put a request on
rec.radio.swap.
Make your
high current radio supply your third or fourth power supply design project.
mike

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