At 14:36 1/15/2009, you wrote:
> I often seen post-sunrise enhancement using an inv-V with
>apex up 30m (<0.2 wavelengths and peak TOA straight up). I believe
>we have the same enhancement from stations in EU/Middle East/AF
>at their sunrise who are using marginal (i.e. high-angle) antennas. This
>may be some sort of high-angle mode which injects the signal into the
>ducting region. Your results might have been very different if you used
>high-angle RX antennas for your tests.
Indeed they might have been, Bill. One of the reasons for writing the
original article was to point out that the engineering was feasible, and that
there were various research possibilities for those with more time and
propagation expertise than myself. These possibilities would include the use
of antennas responsive to different arrival angles, as well as propagation
conditions at different locations relative to a coastal site or to a range of
mountains. Unfortunately, for the most part, all I've had time for has been
the single location, single antenna scenario, but at least it has been over a
relatively long period of time. I'm not aware of anyone doing anything
similar, even in the simple fashion that I have been, since that article was
published.
With the advent of relatively inexpensive software defined radios such as the
RFSpace SDR-IQ, higher quality data can be obtained than was ever possible with
the receivers I have used, and the procedures I've developed can be ported over
to RFSpace's code, which is available on their website. I've done a bit of
this with their SDR-14, but time, or the lack thereof, prevents serious
applications being developed, especially if there isn't time to properly
examine the resulting data.
best wishes,
Nick
VE7DXR
*****************************
Nick Hall-Patch
Victoria, BC
Canada
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