ARRL

ARRL Propagation Bulletin ARLP021 (2008)

SB PROP @ ARL $ARLP021
ARLP021 Propagation de K7RA

ZCZC AP21
QST de W1AW  
Propagation Forecast Bulletin 21  ARLP021
From Tad Cook, K7RA
Seattle, WA  May 16, 2008
To all radio amateurs 

SB PROP ARL ARLP021
ARLP021 Propagation de K7RA

We've had another week with no sunspots.  Our reporting week for
this bulletin runs from Thursday through Wednesday, and this is the
fifth bulletin of the year reporting zero sunspots for the week. The
others were Propagation Forecast Bulletins ARLP003, 4, 7 and 8.  All
of the remaining 16 bulletins had at least one day with sunspots in
the reporting period.

Geomagnetic indices were quiet.  But next Tuesday, May 20 should be
quite active.  The predicted planetary A index for May 16-22 is 5,
5, 5, 12, 30, 15 and 8.  Geophysical Institute Prague expects quiet
conditions May 16-18, quiet to unsettled May 19, active geomagnetic
conditions May 20, unsettled May 21, and quiet to unsettled May 22.

Last week's bulletin lamented the transition from analog television
on Channel 2, because signals on that frequency have been a popular
indicator for 6 meter DX.

Several readers wrote in about the low TV Channels 2-6, and
mentioned possibilities for continuing to use broadcast transmitters
there for propagation beacons.  There are also examples of digital
TV being received a long distance from the transmitter site.

Patrick Dyer, WA5IYX of San Antonio, Texas sent in a number of
useful links, and mentioned a pilot carrier 310 KHz above the bottom
of each DTV channel, useful for detecting skip signals.  For
Channels 2-6, you can plug these frequencies into your scanner:
54.31 MHz, 60.31 MHz, 66.31 MHz, 76.31 MHz and 82.31 MHz.  Of
course, you would want to skip any frequencies that are used
locally.

He sent a link to http://tinyurl.com/5qpykr showing low band DTV
station info.

The site http://tinyurl.com/5z2ocb links to an article about a
Channel 2 DTV signal from Florida received over 1,000 miles away in
New England.  From http://tinyurl.com/6jxet4 you can download a
PowerPoint file with info on using pilot signals to detect a DTV
station below the level that enables a usable DTV service.  If you
don't have Microsoft PowerPoint, you can download a free PowerPoint
viewer from http://tinyurl.com/y5c796.

Pat is an avid TV/FM DXer, and has a web page devoted to his
interests at, http://home.swbell.net/pjdyer/index.html.

Fred Stone, W8LLY of Bellbrook, Ohio is Director of Engineering for
WPTD-TV in Dayton, Ohio, and he noted that post-transition
television will be broadcast on Channels 2-51.  He said FCC records
show Channel 2 stations in Flagstaff AZ, Grand Junction CO, Bangor
ME, North Platte NE, Las Vegas NV, Rapid City SD, and Jackson WY.

Jon Jones, N0JK of Kansas reports widespread 6 meter E-skip openings
May 13, in the USA from 1900z-0300z.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://www.arrl.org/tis/info/propagation.html.  For a detailed
explanation of the numbers used in this bulletin see,
http://www.arrl.org/tis/info/k9la-prop.html.  An archive of past
propagation bulletins is at http://www.arrl.org/w1aw/prop/.  Monthly
propagation charts between four USA regions and twelve overseas
locations are at http://www.arrl.org/qst/propcharts/.

Instructions for starting or ending email distribution of this
bulletin are at http://www.arrl.org/w1aw.html#email.

Sunspot numbers for May 8 through 14 were 0, 0, 0, 0, 0, 0, and 0
with a mean of 0.  10.7 cm flux was 66.4, 67.3, 67.4, 68, 68, 68.3,
and 69 with a mean of 67.8.  Estimated planetary A indices were 4,
3, 5, 3, 4, 4 and 3 with a mean of 3.7.  Estimated mid-latitude A
indices were 3, 3, 4, 3, 3, 3 and 1, with a mean of 2.9.
NNNN
/EX