[Amps] Plate Choke Resonances

[Gary Schafer]

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
> On Behalf Of Jim Brown
> Sent: Saturday, January 30, 2010 1:06 PM
> To: Amps at contesting.com
> Subject: Re: [Amps] Plate Choke Resonances
> 
> On Sat, 30 Jan 2010 12:55:43 -0500, Carl wrote:
> 
> 
> >----- Original Message -----
> >From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
> >To: <Amps at contesting.com>
> >Sent: Friday, January 29, 2010 11:56 PM
> >Subject: Re: [Amps] Plate Choke Resonances
> 
> 
> >> ORIGINAL MESSAGE:
> >>
> >> On Fri, 29 Jan 2010 10:13:37 -0800, "Jim Brown"
> >> <jim at audiosystemsgroup.com> wrote:
> >>
> >>>
> >>>The principal resonance is a parallel resonance with
> >>>its own stray capacitance. You should not have to short
> >>>anything to see this.
> >>
> >> REPLY:
> >>
> >> The purpose of shorting is to find SERIES resonances with the grid
> dip
> >> meter. You need to check for both parallel and series (i.e. with and
> >> without the short).
> >>
> >> 73, Bill W6WRT
> 
> >Oh how true Bill! I was waiting for someone to catch that big error (-;
> 
> My comment was not an ERROR, but an observation. Of course you short it
> to look for series resonances. Yes, you must look both ways. And I
> repeat
> my recommendation to measure the impedance vs. frequency.
> 
> 73,
> 
> Jim K9YC

We usually don't care if the plate choke is parallel resonant or not. The
only time that comes into play might be on 160 or 80 meters if the choke is
too small (too little inductance) and it resonates with the plate tune
capacitor. But then that is a good thing.

73
Gary  K4FMX