[Microwave] Before the Friis equation

[scott at nx7u.net]

May have been too new to make it to textbook.
Are these along the lines of what you're looking for?

K. A. Norton, "The Calculation of Ground-Wave Field Intensities over a 
Finitely Conducting Spherical Earth", Proc IRE v29 p623 Dec 1941
Burrows and Gray, "The Effect of the Earth's Curvature on Ground-Wave 
Propagation", Proc IRE v29, p16, Jan 1941
Eckersley, "Ultra-short-wave Refraction and Diffraction", Jour IEE, v80, 
p286, Mar 1937
K. A. Norton, "The Propagation of Radio Waves over a Plane Earth", 
Nature, v125, p954, June 1935
...and if not these articles, then their citations may be useful.

Terman's "Radio Engineers Handbook" has some of the 1930's developments 
in Section 10.

It appears to me that the initial formulation of the problem was to 
consider the "ground-wave", which is the combination of a direct ray 
(what we'd call Free Space today) and a ground reflected ray.  Then 
consideration was given of antennas high enough above the surface of the 
earth that the "ground reflected ray" was negligible compared to the 
direct ray.  And as such, the study of propagation was not uncoupled 
from the study of antennas.

I looked in Kerr, "Propagation of Short Radio Waves", MIT Rad. Lab. but 
it's mostly meteorological.
Perhaps Silver's MIT Rad. Lab. on Antennas has some early citations of 
the problem.  My copy is in storage.

On 2014-08-16 05:22, Dave Brown wrote:
> Any historians out there?
> I'm currently looking into some experimental work that was carried out
> in the 1930s involving long VHF radio paths. Those involved were
> amateurs but also recent university graduates.  It seems that back
> then, little if anything, was known about calculating free space path
> loss. This is hardly surprising as most research at that time was
> based round propagation from VLF up to HF. Any work at higher
> frequencies was purely experimental with few, if any, practical
> applications in mind for the frequencies beyond 30 MHz.
> 
> The Friis equation, published just after WW2  in Proc IRE for May 1946
> (pdf here)
> http://dsc.ufcg.edu.br/~maspohn/adhoc-grad/papers/Friis%20transmission%20equation/01697062.pdf
> appears to have been the first time that straight forward calculation
> of free space path loss was brought to the attention of the scientific
> and engineering community.
> 
> The early (1930s) texts I've looked at so far fail to mention anything
> beyond use of what appear to be mainly empirical relationships for
> estimating field strength at a distance, which was a prime
> consideration for LF/MF broadcasting.  HF communications was then in
> its infancy and the effect of the ionosphere was barely understood and
> yet to have  a well developed theoretical basis established.
> 
> I'd like to establish whether or not any published work exists that
> predates the Friis article  in dealing with the calculation of free
> space path loss or the related concept of the ratio of received and
> transmitted powers, including the effects of antennas, over the
> theoretical free space path.
> 
> Friis, in his 1946 article, notes that  his equation has been in use
> for some years -" Almost seven years of intensive use" - but makes no
> mention of the concept having been published earlier. This suggests
> strongly that WW2 (and probably radar related research) provided the
> impetus to provide a sound theoretical basis for this type of
> calculation, but if anyone can provide any references to earlier
> relevant published work for me I would be most grateful.
> 
> 73
> Dave
> ZL3FJ
> 
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