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@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Pat Barthelow
> Sent: Tuesday, March 18, 2008 12:12 PM
> To: garyschafer@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@hotmail.com
> http://www.jamesburgdish.org
>
>
> > From: garyschafer@comcast.net
> > To: tonne@comcast.net; amps@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@contesting.com [mailto:amps-bounces@contesting.com]
> On
> > > Behalf Of Jim Tonne
> > > Sent: Monday, March 17, 2008 9:47 PM
> > > To: garyschafer@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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