[SI-LIST] Re: Honey, your conductors are ready!

  • From: Jeff Walden <jwalden@xxxxxxxx>
  • Date: Mon, 17 Nov 2014 12:45:52 -0500

@Kevin ... Multipaction was never considered to be an possible issue?
On Mon, Nov 17, 2014 at 12:20 PM, Kevin G. Rhoads <krhoads@xxxxxxxxxxxxxx>
wrote:

> Regarding "while researching this I discovered why the waveguides of an
> F-14 radar system (AWG-9) were pressurized (this has puzzled me for
> quite a while)."
> I dealt with this issue regularly when I was designing instruments fo
> sounding rocket flights.  The Paschen curve describes minimum breakdown
> potential as a function of density-separation (often expressed as
> pressure-separation).
> I compiled data from multiple sources to have on hand.
> We normally dealt with the issue by not turning high voltage on until
> after exceeding a certain altitude.
>
> Electrical breakdown -- fun stuff.
>
> On 11/16/2014 8:17 PM, Loyer, Jeff wrote:
> > I think Kevin has highlighted the key factor - exceeding the breakdown
> voltage of atmosphere.  I think the key aspect here will be shape of the
> conductor, not the material.  Where this experiment may fail might be the
> sharpness of the corners on the shapes (sharp corners concentrate
> e-fields).  If we can't make a spheroid (and flat piece) without sharp
> corners, we may cause sparks.  I'm guessing the "hot pockets" designs
> carefully smooth their edges.  Of course it will depend on many factors.
> This might be where simulations come in - to figure out exactly when the
> experiment will produce some usable results and when it will produce an
> extra microwave for the shop.
> >
> > And, I owe a special note of gratitude to Kevin - while researching this
> I discovered why the waveguides of an F-14 radar system (AWG-9) were
> pressurized (this has puzzled me for quite a while).
> >
> > Jeff Loyer
> >
> > -----Original Message-----
> > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Kevin G. Rhoads
> > Sent: Monday, November 17, 2014 2:05 AM
> > To: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Re: Honey, your conductors are ready!
> >
> > On 11/16/2014 4:47 AM, Loyer, Jeff wrote:
> >> What I still don't understand is why some metals spark, and some don't
> (it seems that shape plays as much a part as anything, besides having it
> touch the walls).
> >
> > Considering the power, the E-fields are non-trivial and edge
> > concentration effects are relevant.  Proximity to (grounded) metal walls
> > allows spark-overs.  And field-driven arcs are possible, even likely.
> >
> >
> > http://www.scribd.com/doc/84859094/Continuum-Electromechanics-cem-811
> > (Creative commons licensing from MIT OCW)
> >
> > I think we can find somethings of relevance in this textbook as well as
> > the venerable:
> >
> > http://www.scribd.com/doc/100077023/Electric-Arc-Phenomena
> >
> > At the thickness of normal aluminum foil and the likely levels of
> > induced current -- the foil is probably a resistance heater.
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > //www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> >
> > List forum  is accessible at:
> >                http://tech.groups.yahoo.com/group/si-list
> >
> > List archives are viewable at:
> >               //www.freelists.org/archives/si-list
> >
> > Old (prior to June 6, 2001) list archives are viewable at:
> >               http://www.qsl.net/wb6tpu
> >
> >
> > ------------------------------------------------------------------
> > To unsubscribe from si-list:
> > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> >
> > or to administer your membership from a web page, go to:
> > //www.freelists.org/webpage/si-list
> >
> > For help:
> > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> >
> >
> > List forum  is accessible at:
> >                http://tech.groups.yahoo.com/group/si-list
> >
> > List archives are viewable at:
> >               //www.freelists.org/archives/si-list
> >
> > Old (prior to June 6, 2001) list archives are viewable at:
> >               http://www.qsl.net/wb6tpu
> >
> >
>
>
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List forum  is accessible at:
>                http://tech.groups.yahoo.com/group/si-list
>
> List archives are viewable at:
>                 //www.freelists.org/archives/si-list
>
> Old (prior to June 6, 2001) list archives are viewable at:
>                 http://www.qsl.net/wb6tpu
>
>
>


-- 
Jeffrey L Walden

EMC/SI RF analysis and product development
http://www.linkedin.com/in/emcsirf
jwalden@xxxxxxxx
(866)547-5365


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:     
                //www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts:

  1. Home
  2. si-list
  3. Archive
  4. 11-2014