low MHz connector design consultant
in [Design]
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From: tm on 2 May 2010 10:47 "Baron" <baron.nospam(a)linuxmaniac.nospam.net> wrote in message news:hrk0qi$1f2$1(a)news.eternal-september.org... > tm Inscribed thus: > >> >> "Baron" <baron.nospam(a)linuxmaniac.nospam.net> wrote in message >> news:hri41l$ple$2(a)news.eternal-september.org... >>> tm Inscribed thus: >>> >>>> >>>> "Baron" <baron.nospam(a)linuxmaniac.nospam.net> wrote in message >>>> news:hri2ce$910$1(a)news.eternal-september.org... >>>>> mpm Inscribed thus: >>>>> >>>>>> On Apr 30, 10:58 pm, "k...(a)att.bizzzzzzzzzzzz" >>>>> >>>>> For co-axial cables its a function of the ratio of the diameters of >>>>> the conductors modified by the dielectric constant of the >>>>> insulator, or for twin conductor the spacing between them and the >>>>> dielectric constant of the insulator. >>>>> ie (impedance = (138 / e^(1/2)) * log (D/d)) >>>>> >>>> >>>> >>>> It also assumes a match at both ends of the line. >>>> >>>> >>>> Tom >>> >>> ??? >> >> Sure. Take a piece of coax, any impedance, 1/4 wavelength long, and >> short one end. What do you see at the other end? >> >> Now match both ends. What impedance do you see at any point of the >> line? >> >> >> >> >> Tom > > That has absolutely nothing to do with characteristic impedance ! > Hi Baron, I never said it did. Just that matching the characteristic impedance on each end of the line is necessary for the full transfer of power. If the line is mis-matched, the impedance anywhere on the line will be a complex function. Right? Regards, Tom
From: Joerg on 2 May 2010 11:01 krw(a)att.bizzzzzzzzzzzz wrote: > On Sat, 01 May 2010 17:47:51 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >> John Larkin wrote: [...] >>> How he can get 6 dB of loss at low MHz is a mystery to me. >>> >> Send in a kilowatt and see what starts to smoke? > > Smoke the "phut" out of it? > >> I know, I know, that was facetious. Profound apologies :-) > > Yes, with that kind of lump in the line, the transmitter would likely go > "phut" phirst. Not if you build the transmitter right. Mine did it several times. Blew up a coax and also a large two-incher balun. The tubes remained completely unfazed. Ok, when the balun went the antenna-side variable capacitor briefly went into the welding business but that was fixed with 600-grit sandpaper. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 2 May 2010 11:03 Baron wrote: > Joerg Inscribed thus: > >> John Larkin wrote: [...] >>> >>> How he can get 6 dB of loss at low MHz is a mystery to me. >>> >> Send in a kilowatt and see what starts to smoke? >> >> I know, I know, that was facetious. Profound apologies :-) >> > > I've seen the enamel burn off a coil at that power level. :-) > Oh yeah, lots of weird stuff can happen. My strangest episode was when a piece of ceramic turn into bubbly green glass. The rest of that capacitor flew off with a loud bang. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 2 May 2010 12:29 mpm wrote: [...] > I am traveling for a few days, so further thoughts will have to > wait.... > This may be too complicated a discussion for SED anyway. > No laptop? Most airports have free WiFi. Once I sat in the Irish Pub next to gate C1 when connecting in Las Vegas. Held a pint of Guinness up in front of the netbook, hit the snap picture button, emailed it to my wife right from the bar stool :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 2 May 2010 12:31
Baron wrote: > John Larkin Inscribed thus: > [...] >> How he can get 6 dB of loss at low MHz is a mystery to me. >> >> John > > I concur ! 6db is +/-75%. That's still better than the accuracy of budgets set up by politicians :-) -- SCNR, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |