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Propagation Topics. Carl Luetzelschwab K9LA k9la@arrl.net http://mysite.ncnetwork.net/k9la. A Little About K9LA. Novice license WN9AVT in October 1961 Selected K9LA in the mid 1970s Interested in propagation, antennas, DXing , and contesting NCJ Editor from 2002-2007

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Propagation topics

Propagation Topics

Carl Luetzelschwab K9LA

k9la@arrl.net

http://mysite.ncnetwork.net/k9la

FRC 9 Nov 2010 - K9LA


A little about k9la
A Little About K9LA

  • Novice license WN9AVT in October 1961

  • Selected K9LA in the mid 1970s

  • Interested in propagation, antennas, DXing, and contesting

  • NCJ Editor from 2002-2007

  • My wife is Vicky AE9YL – it helps that she kind of understands this ham radio thing

  • BSEE 1969 and MSEE 1972 from Purdue

  • RF design engineer by profession

FRC 9 Nov 2010 - K9LA


What we ll cover
What We’ll Cover

  • Solar Minimum and Cycle 24

  • Recent Science News

  • F2 Region Variability

  • Propagation Predictions

  • 160m Fundamentals

  • 10m Opening to EU on October 11

  • Old QSL Quiz

FRC 9 Nov 2010 - K9LA


Solar minimum and cycle 24
Solar Minimum and Cycle 24

FRC 9 Nov 2010 - K9LA


Our recent solar min
Our Recent Solar Min

Pretty unusual, right?

FRC 9 Nov 2010 - K9LA


A look at all recorded history
A Look At All Recorded History

Note the cyclic nature

Recent solar min certainly unusual in our lifetime, but not that unusual over all recorded history

FRC 9 Nov 2010 - K9LA


Cycle 24 progress
Cycle 24 Progress

  • Solar min in December 2008

  • Smoothed sunspot number and smoothed solar flux steadily rising ever since (in spite of the ups-and-downs of the monthly mean values)

FRC 9 Nov 2010 - K9LA


Latest noaa prediction
Latest NOAA Prediction

Max smoothed sunspot number of 90 and max smoothed solar flux of 140 in early 2013

Kind of looks like the actual results are a bit behind the predictions

FRC 9 Nov 2010 - K9LA


More predictions
More Predictions

Over 55 predictions in the scientific literature

Range from a smoothed sunspot number of 40 to 185

Somebody is going to get it right!

FRC 9 Nov 2010 - K9LA


When will 15m and 10m be back
When Will 15m and 10m Be Back?

  • Let’s assume the NOAA prediction is correct

  • 15m needs a smoothed sunspot number of about 25 (smoothed solar flux of 85) for consistent F2 propagation

    • We’re probably there now

    • CQ WW PH was consistently good

    • CQ WW CW should be, too

  • 10m needs a smoothed sunspot number of about 50 (smoothed solar flux of 100) for consistent F2 propagation

    • I hope we get there in early 2011

    • ARRL DX contests in February and March 2011 have the potential of being good (more than just Carib and S Amer)

FRC 9 Nov 2010 - K9LA


Our very own prediction
Our Very Own Prediction

out of phase with solar min duration

Long solar min points to a smaller cycle

“cycles” – Schwabe 11 yrs

Hale 22 yrs

Gleissberg 88 yrs

De Vries 205 yrs

Halstatt 2300 yrs (from Be10 and/or C14)

FRC 9 Nov 2010 - K9LA


A recent prediction
A Recent Prediction

Annales Geophysicae, 28, 1463–1466, 2010

www.ann-geophys.net/28/1463/2010/

doi:10.5194/angeo-28-1463-2010

Size of the coming solar cycle 24 based on Ohl’s Precursor Method, final estimate

R. P. Kane

Instituto Nacional de Pesquisas Espacias, INPE C.P. 515, 12201-970 Sao Jose dos Campos, SP, Brazil

  • Maximum smoothed sunspot number of 58 +/- 25

  • That’s lower than the NOAA prediction

  • 10m will suffer

FRC 9 Nov 2010 - K9LA


Recent science news
Recent Science News

FRC 9 Nov 2010 - K9LA


1 no more sunspots
#1 - No More Sunspots?

  • Measured the magnetic fields of sunspots for the past 17 years, and data indicates sunspot magnetism is on the decline

  • Sunspots seem to form only if the magnetic field is stronger than about 1500 gauss

  • Solar magnetic fields may become too weak to form sunspots after 2016 or so

  • The technique looks at a spectral line emitted by iron atoms in the Sun's atmosphere

FRC 9 Nov 2010 - K9LA

Livingston and Penn, EOS, July 2009


2 collapsing atmosphere
#2 - Collapsing Atmosphere

FRC 9 Nov 2010 - K9LA


Propagation topics
Data

Pt Arguello ionosonde shows downward trends for both foF2 and hmF2

Other ionosondes show a mixed bag of results

The conclusion: More analysis is needed

Details: November 2010 WorldRadio Online column

FRC 9 Nov 2010 - K9LA


3 storm warnings
#3 - Storm Warnings

FRC 9 Nov 2010 - K9LA


4 lower ionosphere
#4 - Lower Ionosphere

  • Space is just a little bit closer, BBC News, 21Dec08, news.bbc.co.uk/2/hi/science/nature/7794834.stm

  • NASA: Ionosphere not where it should be, UPI, 17Dec08, www.tinyurl.com/3p2pcs

  • These press releases are somewhat misleading

  • What’s not real clear is the data is for equatorial latitudes

  • Not understanding this leads to the erroneous conclusion that the worldwide ionosphere is lower - ionosonde data shows no such trend

  • Details: “Is the Ionosphere Really Lower?” at mysite.ncnetwork.net/k9la under Timely Topics link

FRC 9 Nov 2010 - K9LA


F2 region variability
F2 Region Variability

FRC 9 Nov 2010 - K9LA


A look at ionosonde data
A Look at Ionosonde Data

MUF varied from a low of just under 10 MHz to a high of just above 20 MHz

This is due to the daily variation of solar radiation, right?

FRC 9 Nov 2010 - K9LA


Not quite
Not Quite

  • August 2009

    • Zero sunspots

    • Constant solar flux

  • Solar radiation creates ionization

  • But two other issues contribute to the final ionization

    • Magnetic field activity

    • Events in the lower atmosphere coupling up to the ionosphere

  • Thankfully the E region is more predictable – it’s under direct solar control

    • Solar activity

    • Solar zenith angle

August 2009

FRC 9 Nov 2010 - K9LA


Another subtle effect
Another Subtle Effect

The worldwide ionosphere is not necessarily “in step”

FRC 9 Nov 2010 - K9LA


Propagation predictions
Propagation Predictions

FRC 9 Nov 2010 - K9LA


How do you model the ionosphere
How Do You Model the Ionosphere?

  • It should be obvious that plugging in today’s sunspot number or today’s 10.7 cm solar flux does not tell us what the F2 region of the ionosphere is doing today

  • The developers of the model of the ionosphere for propagation prediction recognized this

  • They were forced to implement a statistical model

  • Thus our propagation predictions are statistical over a month’s time frame

  • The correlation between what the Sun is doing and what the ionosphere is doing is based on a smoothed solar index and monthly median ionospheric parameters

FRC 9 Nov 2010 - K9LA


Review of correlations
Review of Correlations

MUF could be anywhere from 17 MHz to 28 MHz at a solar flux of 170

Bottom line: We do not have daily predictions

Median is predicted – use with variability tables to determine other probabilities

FRC 9 Nov 2010 - K9LA


So what does all this mean
So What Does All This Mean?

  • Let’s do a prediction for CQ WW CW

  • We’ll do it for 15m from Philly to Europe (DL)

  • We’ll use VOACAP

    • 1 KW

    • 13 dBi Yagis

  • I used a smoothed sunspot number of 36 (from http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt)

FRC 9 Nov 2010 - K9LA


Results
Results

15m

10m

Median MUF

MUF

  • On half the days of the month at 1400 UTC, the MUF will be at least 25.6 MHz

  • On 89% of the days of the month at 1400 UTC, the MUF will be at least 21.0 MHz

  • On 27% of the days of the month at 1400 UTC, the MUF will be at least 28.0 MHz

  • Signal Strength

  • The median signal strength on 15m at 1400 UTC is -103 dBW (-73 dBm = S9)

  • The median signal strength on 10m at 1400 UTC is -142 dBW (-112 dBm = S1)

UTC

Unfortunately we don’t know which days will be the good ones

Rule of thumb – MUF can vary about the median by one band and signal strength can vary about the median by a couple S-units on any given day in the one-month period

FRC 9 Nov 2010 - K9LA


160m fundamentals
160m Fundamentals

FRC 9 Nov 2010 - K9LA


Interesting question
Interesting Question

Is propagation on 160m different than propagation on, say, 10m?

Most would answer “Yes”

FRC 9 Nov 2010 - K9LA


No is also a good answer
“No” Is Also A Good Answer

  • An electromagnetic wave on 1.8 MHz follows the same laws of physics as an electromagnetic wave on 28 MHz

  • What “laws of physics” should we look at?

  • The three that tell us

    • Refraction (inversely proportional to the square of the frequency)

    • Absorption (inversely proportional to the square of the frequency)

    • Polarization (Earth’s magnetic field plays critical role)

FRC 9 Nov 2010 - K9LA


Ray trace on 10m
Ray Trace on 10m

  • O-wave and X-wave pretty much follow the same path

    • Index of refraction approximately the same

    • X-wave bends a bit more

    • Apogee approx 240 km

    • Hops to 4000 km

  • O-wave and X-wave pretty much incur the same amount of absorption

    • Approx 2 dB per hop

  • O-wave and X-wave are circularly polarized

On 10m the O-wave and X-wave propagate approximately equally

FRC 9 Nov 2010 - K9LA


Ray trace on 160m
Ray Trace on 160m

  • O-wave and X-wave do not follow the same path

    • Index of refraction significantly different

    • X-wave bends more

    • Apogee approx 170 km for O-wave

    • Hops limited to < 3000 km

  • O-wave and X-wave do not incur the same amount of loss

    • Absorption significantly different

    • X-wave usually considered to be out of the picture when operating frequency is near the electron gyro-frequency

      • ranges from .7 to 1.7 MHz worldwide

    • Approx 17 dB per hop

  • Polarization of O-wave tends towards elliptical (vertical) at mid to high latitudes

160m - shorter hops 160m - more lossy hops

160m – only one characteristic wave propagates

FRC 9 Nov 2010 - K9LA


Multi hop on 160m
Multi-hop on 160m

  • Based on previous slides, multi-hop propagation on 160m is via hops that are short and lossy

    • “Short” is relative – but it’s not 4000 km hops like on 10m

  • Per our present understanding of the lower ionosphere, at night a 1500 Watt signal with quarter-wave verticals on both ends can go about 10,000 km before being below the noise level of our receiving system (usually limited by external noise)

    • Daytime limit around 1000 km

FRC 9 Nov 2010 - K9LA


This suggests another mode
This Suggests Another Mode

Distances greater than 10,000 km are likely due to ducting in the electron density valley above the nighttime E region peak

Ducting incurs less loss due to less transits through the absorbing region and less ground reflections

Key issues: what controls entry into the duct, what controls staying in the duct, what controls exiting the duct?

FRC 9 Nov 2010 - K9LA


Nm7m s work with gcrs

galactic cosmic rays

NM7M’s Work with GCRs

  • Galactic cosmic rays are mostly very high energy protons coming in from all directions – day and night

  • Quiet magnetic field (solar min) lets more in – more ionization in the lower ionosphere

  • Active magnetic field (solar max) keeps them out – less ionization

  • GCR measurement on Earth (and thus impact to ionosphere) is out of phase with solar cycle

FRC 9 Nov 2010 - K9LA


Cgrs and the valley

solar min --------

solar max -------

CGRs and the Valley

  • NM7M’s theory is that galactic cosmic rays play an important role in the valley formation, and thus ducting

  • At solar maximum, not many GCRs ionizing the valley – nice and deep

    • Extremely long distance DXing best at solar max

    • NM7M has some interesting plots of QSO distance vs GCR decrease, but there is conflicting data

  • At solar minimum, too many GCRs ionizing valley – fills up more and all we have left is lossy multi-hop

FRC 9 Nov 2010 - K9LA


W4dr observations personal e mail late december 2009
W4DR Observationspersonal e-mail, late December 2009

“I have been DXing on 160 since 1970, with for the most part above-average antennas.

During this present sun spot minimum (the last 2 years and especially the last 8 weeks) I have worked more polar path stations, Zones 17, 18, 19 and 23 plus some 40's than I have in the previous 37 years. This included my first ever zone 23 on Dec 12.

On the other hand I have not worked any long path or bent path SE Asians in the last 4-5 years.”

N4IS and K1ZM recently reported long-haul DX into SE Asia

Suggests that 160m propagation over the poles is best at solar min, and long distance DXing may need a bit more geomagnetic field activity to keep GCRs out

FRC 9 Nov 2010 - K9LA


10m opening to eu on oct 11
10m Opening to EU on Oct 11

FRC 9 Nov 2010 - K9LA


The path
The Path

  • East Coast reported good 10m opening to EU on Oct 11

  • PJ2T also reported this

  • No data from Goose Bay

    • So we don’t know what was happening on the East Coast end

  • El Arensillo (Spain) gives a good picture on the Europe end

FRC 9 Nov 2010 - K9LA


Ionosonde data
Ionosonde Data

Something happened on or before the 11th

FRC 9 Nov 2010 - K9LA


Space weather
Space Weather

  • It is likely that the gradual increase followed by a gradual decrease in the K index played a role in this 10m opening

  • Ionization targets at F2 region altitudes (oxygen atoms) can be re-distributed in the atmosphere due to an elevated K index

FRC 9 Nov 2010 - K9LA


Old qsls or what deleted entity is it
Old QSLsorWhat Deleted Entity Is It?

FRC 9 Nov 2010 - K9LA










Summary
Summary

  • Cycle 24 is likely to be a small one

    • Along with the next couple of cycles 

  • Carefully read and evaluate science news

  • We don’t have daily predictions

  • 160m is still a tough band to understand

    • For more on propagation on 160m, visit http://mysite.ncnetwork.net/k9la, and click on the 160m link on the left

  • Keep an eye on 10m

FRC 9 Nov 2010 - K9LA


Propagation topics
Q & A

FRC 9 Nov 2010 - K9LA