[TenTec] Omni V Maximum voltage

[Dr. Gerald N. Johnson]

On Mon, 2008-02-04 at 21:02 -0600, Bob McGraw - K4TAX wrote:
> As I recall and I have one on the UHF repeater here, there is no voltage 
> adjust pot.  It is just a big old linear unregulated power supply. 
> Personally, I wouldn't connect my radio to that supply.
> 
> I've used the Astron switching supplies with my Omni series and Paragon 
> series of radios with great success.
> 
> As they say, it's your radio, it's your supply.  Don't let the smoke out of 
> the box because it likely won't work any more.
> 
> And for those that will suggest adding a regulator to the output of the 
> supply, there's not enough head room voltage wise to hold 13.8 volts under 
> full load out of the supply.

That may not be true. It is true for paralleled bipolar pass
transistors, but I've been using a power MOSFET regulator in my hamshack
supply for several year now that needs only .02 volts at the minimum of
the ripple to hold regulation. My transformer is 12 volts RMS
(buck/boost) each side of center with schottky rectifiers. At 30 amps
load the liner supply efficiency is about 85%. The key to my regulator
is that the unregulated supply doesn't droop with 20 or 25 amps load to
less than the desired output plus 0.02 volts. It might actually need
another 0.1 farad of filter capacitor on the unregulated to hold up the
voltage under load. My unloaded voltage is about 16 volts. I could
improve the load capacity by going from schottky rectifiers to
synchronous FETs as rectifiers.

73, Jerry, K0CQ
> 
> 
> 73
> Bob, K4TAX
>