[Amps] grid resonance

[Ian White GM3SEK]

Tom W8JI wrote:
>
>> Tom W8JI wrote:
>>> A mobile whip loaded with a coil is a series resonant
>>> system.
>>>
>>> Are you saying a GDO will not dip on a mobile whip Bill?
>>
>> The bottom of the coil is connected to the chassis through
>> the low
>> impedance of the feed system.  The vertical radiator has
>> capacitance to
>> the chassis (of course it has inductance, too).  Sounds
>> parallel to me!
>
>So the loading coil is like a trap, and the coax sees an
>open circuit?
>
>The idea a GDO can sort "good resonances" that make low
>impedances from "bad resonances" that make high impedances
>seems pretty strange to me. Can you tell me how it does
>that, rather than just  finding some type of  resonance at
>the point where it is inserted?

Has anybody published a detailed analysis of how a GDO works?

Bill gave a good description yesterday, but I mean something that goes 
deeper and includes some verifiable math. 'Coefficient of mutual 
inductive coupling' ought to come into it somewhere.



-- 
73 from Ian GM3SEK