[ARC5] osc. reg.

[Mike Everette]

In my experience, a pair of VR-105s to yield 210 volts is like magic.

Something I have always believed, is in using a very stiff, SEPARATE power supply to run the VFO.  Using what I had available, a transformer from a Zenith TV chassis, which had way-more lil' mils than ever necessary, I got 300 volts DC with only the dropping resistor and two VRs as the load.  When the transmitter was keyed, the unregulated 300 volt DC only varied maybe half a volt; the regulated voltage never even quivered.

The power supply ended up being larger and heavier but I never had any issues with its operation.

I was running between 550 and 600 volts (from another transformer) on the 1625 plates and about 250 volts to the screens, for around 50 watts input.

Them thar solid-state thingies work as well as VR tubes, but they don't light up real pretty.

73

Mike
W4DSE

--- On Tue, 1/1/13, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:

> From: Kenneth G. Gordon <kgordon2006 at frontier.com>
> Subject: Re: [ARC5] osc. reg.
> To: "Darryl Sage" <trifid284 at gmail.com>
> Cc: "ARC-5 List" <arc5 at mailman.qth.net>
> Date: Tuesday, January 1, 2013, 5:15 PM
> On 1 Jan 2013 at 16:46, Darryl Sage
> wrote:
> 
> > Hi  I am looking for a diagram of a solid state
> regulator for my 80
> > meter arc 5
> 
> If you don't mind using VR tubes, connect a VR-105 and a
> VR-90 in series 
> with an appropriately-sized dropping resistor from your +HV
> supply. That will 
> give you 195 VDC of very-well regulated oscillator voltage.
> 
> 
> Or two VR-105s will give you 205 VDC. Both at up to 30 mA.
> The 5-volt 
> difference isn't going to effect anything. 
> 
> I would size the resistor to draw 15 mA through the VR tubes
> with no load on 
> the output. The 1626 draws only a few mA.
> 
> Or you can use Zeners in the same configuration.
> 
> > what I am doing now is using a variac to get the b plus
> on
> > the osc. 200  volts key down
> 
> Variacs, unless you use a REALLY BIG ONE, are very poor at
> regulation.
> 
> > I have a 28 volt  ps. which is not on the
> > variac  Does this setup work to keep chirp down ?
> 
> It could.
> 
> Fellas?
> 
> Ken W7EKB
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