Ive noticed that on some but far from the majority of chokes and it only
appears to happen at the first resonance (lowest frequency).
There is no rule that says you cant have both resonances near the same
frequency. It could be rather interesting if the grid circuit was also
resonant there (-;
Carl
KM1H
----- Original Message -----
From: "Gary Schafer" <garyschafer@comcast.net>
To: "'Carl'" <km1h@jeremy.mv.com>; <dezrat1242@yahoo.com>; "'Amps
reflector'" <amps@contesting.com>
Sent: Sunday, January 31, 2010 12:37 PM
Subject: RE: [Amps] Plate Choke Resonances
>I have done the same. In finding series resonance that the shorted choke
>and
> in circuit (no short) come out the same using a GDO.
>
> But how do you distinguish a parallel resonance from a series resonance?
>
> 73
> Gary K4FMX
>
>> -----Original Message-----
>> From: Carl [mailto:km1h@jeremy.mv.com]
>> Sent: Sunday, January 31, 2010 12:12 PM
>> To: garyschafer@comcast.net; dezrat1242@yahoo.com; 'Amps reflector'
>> Subject: Re: [Amps] Plate Choke Resonances
>>
>> By various methods over the decades, out of circuit, and the open and
>> short
>> procedure. Loosely coupled GDO, spectrum analyzer, and VNA. Note that in
>> the
>> cases where Ive had all 3 methods available at the same time there is
>> close
>> agreement.
>>
>> Carl
>> KM1H
>>
>> ----- Original Message -----
>> From: "Gary Schafer" <garyschafer@comcast.net>
>> To: "'Carl'" <km1h@jeremy.mv.com>; <dezrat1242@yahoo.com>; "'Amps
>> reflector'" <amps@contesting.com>
>> Sent: Sunday, January 31, 2010 11:54 AM
>> Subject: RE: [Amps] Plate Choke Resonances
>>
>>
>> > Carl,
>> >
>> > How did you measure the parallel resonance of the choke?
>> > How did you determine the difference between parallel resonance and
>> series
>> > resonance?
>> >
>> > 73
>> > Gary K4FMX
>> >
>> >> -----Original Message-----
>> >> From: amps-bounces@contesting.com [mailto:amps-
>> bounces@contesting.com]
>> >> On Behalf Of Carl
>> >> Sent: Sunday, January 31, 2010 9:22 AM
>> >> To: dezrat1242@yahoo.com; Amps reflector
>> >> Subject: Re: [Amps] Plate Choke Resonances
>> >>
>> >>
>> >> ----- Original Message -----
>> >> From: "Bill, W6WRT" <dezrat1242@yahoo.com>
>> >> To: "Amps reflector" <amps@contesting.com>
>> >> Sent: Sunday, January 31, 2010 1:43 AM
>> >> Subject: Re: [Amps] Plate Choke Resonances
>> >>
>> >>
>> >> > ORIGINAL MESSAGE:
>> >> >
>> >> > On Sat, 30 Jan 2010 22:27:47 -0700, Larry Benko
>> <xxw0qe@comcast.net>
>> >> > wrote:
>> >> >
>> >> >>
>> >> >>I just ran a simulation with a tube with a 3000 ohm impedance and
>> >> 3000V
>> >> >>peak AC on the plate connected to a 100uH plate choke at 10MHz.
>> >> >
>> >> > REPLY:
>> >> >
>> >> > The problem with your simulation is that the voltage is held to a
>> >> > constant 3000 V. In the real world the "Tesla effect" will cause
>> the
>> >> > voltage to rise far higher and that is what causes the smoke.
>> >> >
>> >> > One real world experiment is worth a thousand simulations, IMO. :-
>> )
>> >> >
>> >> > 73, Bill W6WRT
>> >> >
>> >>
>> >> Ive made it a point over the years to test any plate choke I could
>> get
>> >> my
>> >> hands on and build those in magazine or Internet articles.
>> >>
>> >> Almost without fail the ones using larger than necessary diameter
>> wire
>> >> show
>> >> a pronounced parallel resonance in or very close to a ham band. This
>> >> makes
>> >> me think that the builder went the brute force method to avoid smoke
>> >> since
>> >> #22 or 24 isnt needed at 1200-1500W which is what levels they were
>> used
>> >> in.
>> >>
>> >> Probably the simplest and cleanest 160-10M choke is the old Amp
>> Supply
>> >> version used in all their amps with real transmitting tubes. One size
>> >> fits
>> >> all. Tests in the 5KW+ LK-800C and other versions with the 3500V tap
>> and
>> >> three 3CPX800A7's show absolutely no heating problems on any band.
>> This
>> >> 90uh
>> >> choke has 2 1/8" of #26 on an unglazed 3/4" ceramic form, more
>> properly
>> >> referred to as technical ceramic. Im no chemist but Ive been told
>> that
>> >> the
>> >> porcelain glazed contain some amounts of metal??
>> >>
>> >> Anyway, the series resonances are 12.8 and 49mHz and the parallel
>> ones
>> >> are
>> >> 13.0 and 27.2 mHz. A .001 and .01 uF bypass keeps any pesky RF out of
>> >> the
>> >> electrolytics and wiring. Naturally, on 160M the tank circuit is
>> >> involved as
>> >> part of the choke circuit as already mentioned on here many times
>> over
>> >> the
>> >> years.
>> >>
>> >> Maybe I havent been involved with sufficient voltages and power, Ive
>> >> stopped
>> >> at 10KW in my commercial life, but Ive yet to see a Tesla effect
>> from a
>> >> plate choke. Many times in the bandswitch or Tune cap for other
>> reasons
>> >> but
>> >> nothing to do with choke resonances.
>> >>
>> >> Perhaps the closest Ive been to ham amp choke fireworks is the
>> various
>> >> Dentrons when run on 12M. Remove 4 turns from the top and all is
>> well.
>> >> The
>> >> 1st generation Ameritrons used to do a nice display also when WARC
>> was
>> >> opened. While they were still figuring out a new design I simply
>> >> installed a
>> >> B&W 802 in order to get customers back on the air ASAP.
>> >>
>> >> Carl
>> >> KM1H
>> >>
>> >>
>> >>
>> >>
>> >> _______________________________________________
>> >> > Amps mailing list
>> >> > Amps@contesting.com
>> >> > http://lists.contesting.com/mailman/listinfo/amps
>> >>
>> >> _______________________________________________
>> >> Amps mailing list
>> >> Amps@contesting.com
>> >> http://lists.contesting.com/mailman/listinfo/amps
>> >
>
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