[600MRG] Power Supply Ideas

[Frank Lotito]

A suggestion - The "Mastech HY3005F-3" power supply, or something similar.  I have one of these for my 630 meter setup.  It is an adjustable and reasonably well regulated linear supply with a current fold-back feature.  This model allows me to parallel the unit's 2 adjustable supplies. (By trial and error I know this voltage is goof  / idiot proof.) If I follow my "SOP for startup and shut down," I can conveniently lower the supply's voltage to something like 14 VDC for a cold-startup. If all seems well, I then "slowly" bring up the power supply voltage to where I want to be.  There are numerous parts houses distributing this brand of power supply.  

Thinking out loud - (1) There's nothing wrong with the 3-terminal regulator chip / paralleled 2N3055 approach - if you can scare up a suitable power transformer.  For Class D amplifier application, you do not need "gnat's eyelash" regulation and super quiet filtering.  Be careful, too high of a raw DC voltage taxes the series pass regulator design. (2) Why not an adjustable output voltage switching power supply?  On receive your TR system can "switch off" the switching power supply if the model switcher you chose is to noisy for the band(s) you listen on.  Maybe somebody out there already does this?

When I purchased my ICOM 746PRO a number of years ago there was a promotion, buy the rig, get the companion ICOM switching power supply for freebie.  At that time I had a few linear design fixed voltage 13.6 VDC supplies.  I used one of the linear power supplies  for my new ICOM.  However at a later date I wound up using the freebie ICOM switcher for my ICOM plain-Jane 706 on 2, 6 and 10 meters.   No problems.  Of course, a testimonial for 2, 6 and 10 meters is not a rock solid endorsement for adequacy below the AM Broadcast band.  Maybe someone can expand on the quietness of new design switching power supplies for 600 / 630 / 2200 meter applications? After all, in recent years, if my memory serves me correct,  all the "name brand"  transceiver manufacturers offer only switching supplies for their products...is that correct?

73 Frank Lotito  K3DZ / WH2XHA   grid square FN00
________________________________________
From: 600MRG <600mrg-bounces at w7ekb.com> on behalf of Steve Flood <kk7uv at bresnan.net>
Sent: Monday, February 27, 2017 7:14 AM
To: 600mrg at w7ekb.com
Subject: [600MRG] Power Supply Ideas

I have built a Class D transmitter kit from G0MRF.  I am now in need of
building or buying a power supply.

Ideally I would like something variable from 18-24v, and linear regulated.
The most likely operating condition for the supply will be 20v at around 6
amps.   My existing Acopian supply is a fixed 24v/5A.  I see numerous cheap
switching supplies on the web that operate 0-30v and 0-20A, but I am not
fond of switching supplies.



While looking at homebrew designs I see the use of three-terminal regulators
such as the LM338 and pass transistors like the 2N3055.   These devices and
designs are now seemingly becoming obsolete.



I have not been able to find 'modern' homebrew designs on the web.  So I am
now wondering if anyone in the group can steer me in the right direction.



Thanks,

Steve KK7UV/WH2XNV



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