locked Re: Q65 in less favourable condx? #Q65


Joe
 

Hi Jim and all,
Scatter signals are so highly variable that the only way to make
statistically reliable quantitative comparisons of different sumodes is
to transmit and receive them simultaneously.
Very interesting. Given the highly variable nature of propagation and
the different modes of which we try to take advantage, it would be
interesting to see this sort of work repeated on multiple days and at
different times of day.
Probably it will not surprise you that we've done some of this, especially with respect to time of day.  It's very easy to show that ionoscatter conditions are best around mid-day and worst around 7 or 8 PM local time. 

But we decided not to spend time on more extensive tests with respect to time of year, but rather to spend some time in a good research library.  Steve and I have access to excellent ones at the University of Illinois and Princeton University, respectively.

D-Region ionospheric scattering at VHF was studied exhaustively in the late 1950s.  An excellent summary of such studies carried out by the Central Radio Propagation Laboratory of the US National Bureau of Standards was published in 1961, and I've posted a copy here:
https://physics.princeton.edu/pulsar/k1jt/NBS_D-region_scatter.pdf

For a summary of diurnal, seasonal, and frequency dependence of signal strengths see their Figure 6.

  -- 73, Joe, K1JT

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