[ARC5] FCC General exam

[Fuqua, Bill L]

  No, the F layer at night  is the residual ionized atoms left after no Sun light is
shining on it. That is why you get such good DX on 160 80 and 40 meters
at night. Because the density of the atmosphere is low at higher altitudes the 
atoms and ions are further away reducing the chance of recombination. The 
electrons are what actually do the refraction. The interact with each other 
like balls with springs between them trying to push them apart. They are resonant.
This is called the plasma resonant frequency. These act sort of like the parasitic 
reflector on a bean antenna. Very loose analogy but the simplest I can come up
with just now. 
  An atomic physicist and  I sat down at lunch one day and talked about the plasma
resonance formula and he said it was hard to derive because it is done in 3 dimensions
I suggested trying to derive in in one-dimension and with a couple of napkins and felt 
point pen we came up with the same formula.  This was a calculation of plasma resonance
vs electron density. 

73
Bill wa4lav
 

________________________________________
From: Geoff [geoffrey at jeremy.mv.com]
Sent: Sunday, November 24, 2013 8:34 PM
To: Fuqua, Bill L; ARC 5
Subject: Re: [ARC5] FCC General exam

And the E layer is highest just after sunset according to what I just read.
Without sunspot activity there is no F layer after dark.

Carl


----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: "Geoff" <geoffrey at jeremy.mv.com>; "ARC 5" <arc5 at mailman.qth.net>
Sent: Sunday, November 24, 2013 6:25 PM
Subject: RE: [ARC5] FCC General exam


  Well, the F1 and F2 layers are at a lower altitude in the day and merge
into
the F layer at a much higher altitude at night.
  So the answer should be B.
  The propagation depends greatly on frequency.
Find some reference to the ionosphere via google or book.
73
Bill wa4lav

________________________________________
From: Geoff [geoffrey at jeremy.mv.com]
Sent: Sunday, November 24, 2013 6:07 PM
To: Fuqua, Bill L; ARC 5
Subject: Re: [ARC5] FCC General exam

----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: "ARC 5" <arc5 at mailman.qth.net>
Sent: Sunday, November 24, 2013 5:10 PM
Subject: [ARC5] FCC General exam


>  Here is a question that I believe they have wrong on the General Exam.
>  What is the answer with out looking it up.
>
> G3C02 Where on the Earth do ionospheric layers reach their maximum height?
> A. Where the Sun is overhead
> B. Where the Sun is on the opposite side of the Earth
> C. Where the Sun is rising
> D. Where the Sun has just set


I would choose D. Where the Sun has just set
If discussing the E layer anyway.

Carl



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