Hi.

I had a situation where I hooked up a power cord backwards and the radio
was protected by the diode, but the Astron RS20A belew the SCR, the voltage
regulator and the pass transistors when presented with a shorted load.  Be
wary of this if you use Astron power supplies--I have had two of them take
this failure mode.  Their current limiting circuitry is insufficient to
protect the supply from an accidental short circuit, and they do blow their
cool very quickly.  To my way of thinking, a blown power supply is only
slightly better than a blown radio.  Either way, you are off the air until
you can either get someone to repair it or the friendly brown truck brings
you a new one!

73, de Lou K2LKK

      At 08:18 AM 1/7/2005 -0500, you wrote:
>I'd never depend on that diode to protect against hook it up backward,  lost
>a radio that way that was supposedly protected and that was with sighted
>help, kid forgot black was negative and red was positive. I don't let him
>forget it either.
>----- Original Message -----
>From: "Howard Kaufman" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Friday, January 07, 2005 7:29 AM
>Subject: Re: accessible VHF equipment
>
>
> > Eric, their are two wires that go from a power supply to the radio.
> > One is positive and 1 is ground.  The radio is protected by a diode to
> > protect against reversing the wires.
> > The way it works is the right one.  The other is the wrong.  On the choice
> > of radios, how much power do you need to accomplish what you want to
> > do?  How intense is the RFI in your area?
> > What are your antenna options?  How many bands and which ones do you need
> > in your area?
> > What else do you want to do with the radio?
> >

Louis Kim Kline
A.R.S. K2LKK
Home e-mail:  [log in to unmask]
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Work Telephone:  (585) 697-5753