[Amps] Power transformer for 600 watt rig

[Gary Schafer]

Hi Pat,

The biggest problem with a choke input filter is the transient response of
the choke with SSB. It will allow the voltage to dip quite a bit on some of
the voice peaks as the amplifier demands current. A supply with no choke
doesn't have those kind of problems. A tuned choke on the other hand will
act like a capacitor input filter and will not have the transient problems
either.


73
Gary  K4FMX

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Pat Barthelow
> Sent: Tuesday, March 18, 2008 12:12 PM
> To: garyschafer at comcast.net; 'Jim Tonne'; 'Amps @Contesting.com'
> Subject: Re: [Amps] Power transformer for 600 watt rig
> 
> 
> This is quite informative...Question, From Gary's comment about Secondary
> Resistance, and choke input power supplies, not sufficient for SSB dynamic
> regulation, if one has available an older power supply, that is choke
> input, you need relatively low secondary resistance....Does the choke
> resistance have a lot of influence there also?   What are some typical
> values of HV choke resistances?   If so, then I think what you are saying,
> is  some (most?) choke input power supplies will have regulation issues
> with SSB.
> Yes/No?
> 
> All the best,
> Pat Barthelow    (916) 315-9271
> aa6eg at hotmail.com
> http://www.jamesburgdish.org
> 
> 
> > From: garyschafer at comcast.net
> > To: tonne at comcast.net; amps at contesting.com
> > Date: Tue, 18 Mar 2008 11:08:59 -0400
> > Subject: Re: [Amps] Power transformer for 600 watt rig
> >
> > Hi Jim,
> >
> > No I don't have LTspice.
> >
> > What I was saying about what type of service the power supply is to
> expect
> > to see matters a great deal. A transformer (a good one) that is to be
> used
> > with a voltage doubler might have a secondary resistance in the
> neighborhood
> > of 15 ohms.
> >
> > A transformer to deliver the same power supply voltage using a choke
> input
> > filter can get by with a transformer secondary resistance of a couple of
> > hundred ohms.
> > The dynamic regulation of the latter will be fine for an AM or FM rig
> but
> > not acceptable for SSB.
> >
> > 73
> > Gary  K4FMX
> >
> >
> > > -----Original Message-----
> > > From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
> On
> > > Behalf Of Jim Tonne
> > > Sent: Monday, March 17, 2008 9:47 PM
> > > To: garyschafer at comcast.net; 'Amps @ Contesting.com'
> > > Subject: Re: [Amps] Power transformer for 600 watt rig
> > >
> > >
> > > Gary:
> > >
> > > Do you have LTspice?  I will plug those numbers
> > > into the transformer model to complete the design.
> > > The numbers I quoted are adequate for the problem
> > > as stated.
> > >
> > > - Jim Tonne
> >
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