Welcome to my observations on
HF Digital Band Conditions
As an experienced and
active HF digital operator, I operate all the HF bands or at least try to listen
on all bands daily to find where the digital action is. Here in the North
Western United States, I find propagation into Europe to be the greatest
challenge because the direct path from here requires a polar route. The phase
distortion received on signals over the pole has kept me from using the narrow
mode PSK31 for these contacts and I often experiment with more robust modes like
MFSK16 and Hellschreiber. Besides seeking DX contacts on the upper bands, I
enjoy the short skip opportunities on the low bands, especially at night. My
operating profile is usually a few hours each evening and if I am lucky, a few
hours during the day on weekends and holidays. I will periodically update my
observations on HF Digital activity so that you may have something to compare
your experience with.
A complete description and
picture of my station is found HERE. My HF Log is found HERE.
Since there is no, and
probably will never be any, specific band plan for us new breed of digital
operators (sound card programs); I hope these observations will help you focus
on what the latest operating trends are. Please continue to be courteous to all
the ham signals you find sharing the band. See you on the screen...
- Mar 2003:
The low bands continue to be
open and active each night, with good digital contacts on 40 and later on 80
meters around 3.851 to 3.854 Mhz. Activity is split these days between PSK31
and MFSK16 modes. Solar activity has dropped way off in Feb as we continue the
slow decline toward a sunspot minimum. Fewer and shorter openings are found
above 20 meters now. The 20 meter band remains fairly steady for regional skip
and gray line DX in the mornings and evenings. I have begun to hear digital
signals from over the pole (Europe) at night in the last week of Feb; and this
is a trend that should continue into Spring. My strategy now is to monitor
MFSK16 mode on both 80 and 20 meters each evening, this way I won't miss any
opportunities to work DX when the polar path is open. MFSK16 and Hell modes
are the most reliable modes for polar path work.
- Jan 2003:
The Geomagnetic disturbances from
earlier in the Fall have subsided now and propagation on the low bands has
returned on schedule. The activity has shifted from the high bands to the
lower bands with more opportunities available at night now than we have seen
since last Spring. The 20 meter band is often "closed" now after day light
hours and the activity has shifted to the 40 meter band and then to the 80
meter band. The 160 meter band is also "open" at night now but very little
digital activity is found below 80 meters. This winter I am hearing less
Hellschreiber and MT63 activity on the low bands, but much more MFSK16 mode
operation along with the usual PSK31 operation. There are probably two reasons
for the popularity of MFSK16 recently. Digi operators have discovered that the
Forward Error Correction and interleaving feature found in MFSK16 (not found
in PSK31) is needed on the low bands, so they can enjoy the same level of text
quality that they find with PSK31 on the high bands. Recently a new dimension
to MFSK16 operation was added by the popular sound card program MixW. Color
pictures can now be exchanged on the digital bands while using MFSK16 as the
QSO mode. A narrow band version of Slow Scan TV is called during a QSO to send
the analog video signal inside the band width of the normal MFSK16 signal.
Most of this activity can be found on 14.081 Mhz during the day (where it is
becoming increasingly harder to find a clear frequency ;-). The full impact of
this technique is yet to be seen on the digital bands! Meanwhile, operations
on the higher bands, like 15 and 10 meters, is limited now to day light hours,
with good skip to South America and Asia from the west coast in the late
afternoon. We can look forward to 20 meter polar path openings at night later
this Winter. MFSK16 and Hell modes will provide the most reliable
communications for PC sound card operation during this period.
- Nov 2002:
Sunspot activity has begun the
expected decline, however higher than expected Geomagnetic activity has
effected the bands for much of this last period. High Planetary A indices
began on Sep 30th and never settled down for long during the entire month of
October. All things being equal, we should now be in store for a long period
of undisturbed band conditions. Fall is the time for trans-equatorial skip on
the high bands and a transition into more opportunities for skip conditions
over the North Pole region. Also the promise of better 80 meter opportunities
with lower noise and longer skip is a feature of this time of year. The W1AW
morse code practice transmissions have been heard here in Oregon very clearly
this last week near the digi band on 80 meters. The 3.581 Mhz digi band is not
bothered by Pactor MBO QRM as is the 40 meter and 30 meter bands. (The skip on
the low bands will follow the sunset, so please stay up late to work Oregon on
80 meters ;-) As we get closer to Winter, the 10 meter band will improve as
well as will the 15 meter band. Now that cold weather and early nights have
returned, we can all find an excuse to enjoy more time on the bands!
- Sept 2002:
Higher than expected solar
activity this summer has played havoc with most of the published predictions
for band conditions. Solar storms during August kept the A Indices high with
poor skip conditions the result on to many days. This is settling down for the
first week of September with noticeably better skip conditions. Stronger
signals from the South Pacific on 20 meters in the evening, and Asia is being
heard again on 15 meters. Look for some of the best DX conditions since last
Spring to occur on 40 through 10 meters this Fall! Activity on 40 meter PSK31
is still good in the evening and will increase along with activity on the 80
meter band as noise levels begin to drop. More MFSK16 is being heard on 40
meters just above the North American PSK31 frequency. It seems that the
traditional MFSK16 band of 7.080 may be changing this year to 7.073 Mhz? I
hope and expect to hear more MFSK16 operation along with the PSK31 signals
around 3.582 Mhz this Fall. MFSK16 mode is particularly useful on 80 meters to
eliminate the missed letters on PSK31 caused by the QRN and multi path
distortion. The 20 meter band will provide 24 hour skip conditions on many
days this Fall. MFSK16 is becoming more popular world wide as are the Hell
modes particularly on 20 meters. This is a good time to experiment with new
sound card modes, and you can find this activity around 14.081 Mhz. Summer is
gone and the bands are back!
- July 2002:
Summer time conditions are now in
full force with some predictable changes to the bands. My biggest surprise so
far has been the 40 meter band and how well it is holding up to this point.
Good skip signals are still heard from dusk till after dark with the band
noise not yet reaching objectionable levels here in Oregon. An increase in
Pactor MBO activity (QRM) in the 40 meter PSK31 band is probably an indication
that summer travel has begun. Eventually 40 meters may become as noisy as 80
meters has been since June. Because we are still rather high on the back side
of solar cycle number 23, I am finding 20 meters to be my "go to" band this
summer, and even 15 meters has some good DX opening before dark sets in. South
America and the Pacific are heard best here in Oregon, with some openings to
Europe and the South Pacific still being worked. I am expecting better signals
to Asia as we move closer to Fall. With the big drop in solar numbers for
June, 10 meters has been mostly quiet as was expected for Summer. Summer is
the time for sporadic openings on 6 meters if you have the patients for that.
Much of the lack of amateur activity during the summer is caused by a loss in
interest, as I have often suspected was the case. A survey taken last summer
proves that Hams are less active on the air in summer time. Add your feelings
at: http://www.eham.net/survey/376
- May 2002:
All digital activity on 80 meters
was down in the last half of April, as Winter band conditions begin to give
way to the noisier low band conditions of Summer time. 40 meters was
noticeably off as well for the same reason, but good skip was still available
there as the Geomagnetic Index was low for most of this last period. During
these less then optimum conditions on the low bands, don't forget to take
advantage of MFSK16 for reliable contacts. A CQ on 40 meters around sunset
could yield some surprising results! 20 Meters has been the most fun for me
during the last 2 months! Each evening on MFSK16 around 14.081 (USB) the
signals from over the pole have been very reliable. A major Solar and
Geomagnetic storm that occurred at the end of April has temporarily disrupted
this path, but look for this path to continue through Spring. Openings in the
other direction to ZL/VK land are also more frequent at this time.
Hellschreiber Activity Day was a bust this year; probably because IZ8BLY no
longer updates his web site that would collect the data and publish the
contest results. Plenty of Feld Hell and FM Hell operators are around 14.080
at night and weekends. If you don't hear any Hell signals, just give a CQ and
they will find you. 10 and 15 meters remain active most days, but activity now
falls off sharply after sunset. DX to South America and Japan is mainly what I
hear there on PSK31. We must enjoy 10 meters while we can because Summer
conditions are coming...
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