[Lowfer] need a circuit for DC to DC Boost converter

[Andy - KU4XR]

I have saw pics of that setup !!! Probably a little bit Over-Kill
for a lowFER PA power supply; hi - hi ::::

I bought a lot of 3 - 32v/16v HP wall-wart SMPS off ebay. The are
defective, although brand new. All 3 have the worst noise I have
ever seen on a SMPS before. Connecting them to any of the LF gear
and the noise is imposed onto the transmit. The linear transverter
goes nuts !! and the PA can't handle the noise on the voltage.
The convienience of the dual voltage supply is nice, but the same
outcome can be accomplished with a single voltage, and regulated
down.

The 18 volt HP printer supply I have is at 1.5 Amps, plenty of " I "
for a doubled voltage, but looks like I will be the same as building
another supply to work with this one. Not worth the time, and money.

Ralphs idea of series supplies might be the answer. 18 & 12 volts 
will put me at 30, and then use the adjustable regulator for the
25 volts I have been using on the PA, then tap off the 12 v side to
run the transverter. That's probably what I'll do for now just to
get running again.

Hope everyone has a great weekend. Looks like the receive cndx have
improved now.  73 to all :::


Andy - KU4XR - EM75xr - Friendsville, TN. USA
LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
Coordinates:  N:  35º 43' 54" - W:  84º 3' 16"
http://www.myspace.com/beaconxr
http://webpages.charter.net/ku4xr/


--- On Fri, 4/9/10, Mike.WE0H <we0h at gmx.com> wrote:

> From: Mike.WE0H <we0h at gmx.com>
> Subject: Re: [Lowfer] need a circuit for DC to DC Boost converter
> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
> Date: Friday, April 9, 2010, 1:10 AM
> Build the Tower of Power. Ralph can
> fill you in on what that is.
> 
> 12 x 3 = 36 or 7 x 5 = 35
> 
> Mike
> WE0H
> 
> 
> 
> Ralph-W5JGV wrote:
> >> I have an 18 Volt DC supply. I want to convert the
> voltage to
> >> 36 Volts DC to power my lowFER PA. Will anyone
> point me to a
> >> circuit to do this ?? I suppose minimal parts
> count, low ripple,
> >> 500 mAmp power handling.
> > 
> > 
> > Since you don't need a lot of current, here are a
> couple of ideas:
> > 
> > 1) Find another 18 volt power supply and connect the
> two supplies in series.
> > 
> > 2) Scrounge through the local thrift stores for some
> used inkjet printer
> > power supplies.  I have found several switching
> power supplies rated at
> > 30-40 volts DC @ 300-700 mA at my local thrift
> store.  The HP inkjet
> > printers commonly use power supplies in that range.
> > 
> > Since all of the wall-wart and brick-style switching
> power supplies have
> > isolated outputs, you can easily connect them in
> series.
> > 
> > Good luck!
> > 
> > 73,
> > 
> > Ralph  W5JGV - WD2XSH/7