[600MRG] MF/LF Ionosphere at Sunrise

[D.J.J. Ring, Jr.]

Excellent work.

73

David
N1EA
/18
On Dec 18, 2015 5:53 PM, "James Hollander" <mrsocion at aol.com> wrote:

>
>     SNR sequences  between TX/RX stations’ sunrises (SR) on12/6/2015
> suggest  propagation-relevant SNR dynamics  for  stations  at each  end  of
> paths  on both 2200m and 630m. Basically, I  use  the oncoming
> terminator-caused  absorption  in the  D-layer  as  apoor man's way  of
> looking at the  elevation  angle  distribution  of incoming RF signal rays
> at MF/LF.
>     Data: Since  directive antennas  aren't available to  us  atMF/LF to
> distinguish  arrivingelevation angles, the  idea is to letMother Nature
> help us. One focuses  onWSPR SNR data for geographic paths that  are
> relatively free  from storm noise  and that support SNRs strong enough to
> last from sunrise SR  at the  eastwardstation until sunrise SR  at the
> westward station.
>     Method: I picked 2200/ 630m TX/RXs on relatively Tstorm-free pathswith
> strong SNRs, even  if rainy  in Pacific NW. I subtracted consecutive
> SNRsto  difference those SNRs  and looked for peaks  in the  difference
> results. Also, I simply scrutinizedthe  original SNR sequences  for
> stairsteps.
>      Since WSPR slots  are 2 minutes long, the  SR-SR time interval
> between the  sunrises preferably encompasses  at least  ten (10)
> consecutive WSPR decodes  at  theTxPct used (WSPR TX duty cycle). TxPct 50%
> is  preferable to give good data, but not required for this work.
>      Results: I found SNR stairsteps at ¼ & ¾, one-quarterand
> three-quarters of the SR-SR time interval. These SNR stairsteps  indicated
> RF signal rays penetratingD-region ¼ & ¾ of way along paths between
> XND-w7iuv on 2200m  and between XXP- kk6eew 630m.
>      Conclusion: Try drawing  signal  raylines  on  an  altitude diagram
> from TX ground level  through the D-region one-quarter 1/4 way alonga path,
> and from RX ground level back up through the D-region three-quarters3/4 way
> along the path. The lines meet  at  a  signal reflection point lying  about
> twice  as high  as  theD-region altitude.  So  the  reflecting region for
> those 2200m and 630mpaths  apparently lies  about twice  the height of the
> D-region.
>     E-region: An actual reflecting region  around sunrise  at twice the
> D-region height means  it’s probably the E-region  of the  ionosphere  and
> not the  much-higher F-region.  If  that seems like old news--fair
> enough--it'smost  interesting nevertheless tosee  actual SNR sequences
> givingspecific support to  what others maytell us.
>    Further work: Moreover, I’ve seen SR-SR SNRsequences can be more
> complicated. Studying those sequences can lead  to  a  more realistic
> picture of  actual MF/LF propagation  around sunrise SR than  a
> single-rayreflection picture gives.
>     If you have comments or simplywould like more information about this
> use of WSPR SNR information, pleasecontact me at mrsocion at aol.com.  73,
> Jim H W5EST
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