Re: [IRCA] Oregon Cliff (Cape Perpetua) Ultralight TP's and DU's for 8-19

[Mark Connelly <markwa1ion@xxxxxxx>]

<<
It's hard to believe that we were listening on the same planet Gary, 
let alone the same coast, though admittedly, I'm quite a way from the 
open Pacific here.   As I said yesterday, that morning was pretty 
much the biggest stinker this summer here.


best wishes,


Nick
>>


My home locations have always been a fairly easy commute to TA-capable shore sites:
e.g.
Arlington, MA: 7 miles (11 km) to Revere Beach
Sudbury, MA: 20 miles (32 km) to Boston waterfront
Billerica, MA: 15 miles (24 km) to Salem / Marblehead
South Yarmouth, MA: 12 miles (19 km) to Chatham / Orleans


These are air distances for typical 50-75 degree Euro bearings.  Road distances to DXpedition sites are typically a bit more if only because the shore is heavily developed and only offers certain areas useful for DXing from the car.  In my present case (S. Yarmouth), because of the contour of the shore, the drive to a usable site is actually shorter than the 50-75 degree bearing air distance house-to-shore.


In all cases, the differences between home sites and the coastal DXpedition sites are HUGE.  Some stations were routinely 30-40 dB stronger at the Granite Pier site in Rockport, MA versus less than an hour's drive away at Billerica.  The 1544 (later 1550) Algerian clandestine station was one station which consistently exhibited this whopping difference.  Long term comparisons were easy to make since I could use the same in-car receiver and rooftop antenna.


East Coast inland versus shore differences are greatest in pre-sunset initial fade-ups and during aurora.  The thinking is that the lower the arrival angle of the incoming station, the more difference near-field ground conductivity makes.  There are numerous stations that cannot be heard at home sites on big antennas yet can be heard from time to time on a 2m by 2m car-roof loop at nearby beach sites.


If a station arrives at a higher angle, the location characteristics are less critical and your inland signal may only be 15 to 20 dB degraded from what is noted at the shore.  Old 1314 Norway during prime high latitude conditions (in mid/late evening) fell into this category.  Sunrise at the European transmitter end could contribute to a higher incoming angle at the USA receiving end because an ionospheric tilt may contribute to fewer skip hops being required.


On groundwave, as with low-angle skip, the differences are huge. V-Soft shows 660 WFAN (NYC) running 6.24 mV/m at Falmouth, MA 02543 (shore) and 0.45 mV/m at South Dennis, MA 02660 (about 15 miles / 24 km inland for 255 degree bearing towards station).  In decibels, this equates to a 23 dB drop - and that's for a LOW-band station.  A high-band station would show an even greater overland signal deterioration.  The V-Soft groundwave variations don't look too different from what is routinely observed with low-angle long-haul DX skip.


Mark Connelly, WA1ION
South Yarmouth, MA
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