Transcript
Page 1: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Selected Topics in PropagationSelected Topics in Propagation

Carl Luetzelschwab K9LACarl Luetzelschwab K9LA

[email protected]@arrl.net

Page 2: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

What We’ll Cover in This What We’ll Cover in This SessionSession• An Update on Cycle 24An Update on Cycle 24

– Will it be an underachiever?Will it be an underachiever?

• The M-FactorThe M-Factor– Some theory about one of the basic parameters of Some theory about one of the basic parameters of

the ionospherethe ionosphere

• Sunspots and Solar Flux During Cycle 23Sunspots and Solar Flux During Cycle 23– An interesting anomaly – not sure what it says yetAn interesting anomaly – not sure what it says yet

• Ionosphere-Ionosphere ModesIonosphere-Ionosphere Modes– There’s more than multi-hop out thereThere’s more than multi-hop out there

Page 3: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

An Update on Cycle 24An Update on Cycle 24

Page 4: Selected Topics in Propagation

Solar Min Between Cycle 23 and 24 and Cycle 24 Ascentin terms of 10.7 cm solar flux

50

55

60

65

70

75

80

85

90

95

100

J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N

2006 2007 2008 2009 2010 2011

10.7

cm

S

ola

r F

lux

monthly mean

smoothed

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Latest DataLatest Data

minimum

Smoothed 10.7 cm solar flux is still rising

Page 5: Selected Topics in Propagation

Solar Min Between Cycle 23 and 24, and Cycle 24 Ascentin terms of sunspot number

0

5

10

15

20

25

30

35

40

45

50

J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N

2006 2007 2008 2009 2010 2011

Su

nsp

ot

Nu

mb

er

Cycle 24 monthly mean

Cycle 23 monthly mean

smoothed

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Latest DataLatest Data

minimum

Page 6: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Review of the PredictionsReview of the Predictions

These are from the Solar Cycle 24 These are from the Solar Cycle 24 PredictionPrediction

Panel (NOAA, NASA, ISES, and other Panel (NOAA, NASA, ISES, and other personnel)personnel)

140

9090

Page 7: Selected Topics in Propagation

The Latest Prediction

There may be an updated prediction (lower) from the Solar Cycle 24 Prediction Panel

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Page 8: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Marshall Space Flight CenterMarshall Space Flight Center

Similar prediction to Kane, “Similar prediction to Kane, “Size of the coming solar cycle 24 based onSize of the coming solar cycle 24 based on

Ohl’s Precursor Method, final estimate”Ohl’s Precursor Method, final estimate”, Annales Geophysicae, July 2010, Annales Geophysicae, July 2010

59

A lot of evidence pointing to small Cycle 24

Page 9: Selected Topics in Propagation

But . . . . . . .

• Not everyone agrees that Cycle 24 will be so small• Recent prediction in Solar Physics

– Maximum of 131 +/- 20– Maximum in July 2012 +/- 4 months– From R. S. Dabas and Kavita Sharma, Prediction of Cycle 24

Using Geomagnetic Precursors: Validation and Update, Solar Physics, Vol 266 No 2, pp 391-403, July 2010

• This would be good for the higher bands – and for 6m F2

• If Cycle 24 is a small one, though, 6m F2 propagation will take the biggest hit– Thank goodness for summer E region propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Page 10: Selected Topics in Propagation

Predictions in GeneralPredictions in General• Over 60 predictions for Cycle 24

– Maximum smoothed sunspot number from 40 to 185

• Common forecasting methods– Statistical methods: length of Cycle n correlated to maximum of

Cycle n+1, maximum R12 correlated to minimum R12

• Generally gives low Cycle 24– Geomagnetic precursor methods: Ap, aa, and number of

magnetically disturbed days correlate to next maximum• Unfortunately can give widely varied answers depending on assumptions

– Polar field precursor method: strength of Sun’s polar field correlates to next cycle

• Gives small Cycle 24– Solar dynamo method: the conveyor belt theory

• Unfortunately can give widely varied answers depending on assumptions

• Summary of forecasting methods from K. J. Li, et al, A brief review on the presentation of cycle 24, the first integrated solar cycle in the new millennium, Annales Geophysicae, 29, 341-348, 2011

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Page 11: Selected Topics in Propagation

Recent NASA NewsRecent NASA News• ““Researchers Crack the Mystery of the Researchers Crack the Mystery of the

Missing Sunspots”Missing Sunspots”– Solar scientists claim they’ve developed a Solar scientists claim they’ve developed a

new computer model of the sun's interior new computer model of the sun's interior that gets the physics right for all three that gets the physics right for all three aspects of the sunspot generation process aspects of the sunspot generation process --the magnetic dynamo, the conveyor belt, --the magnetic dynamo, the conveyor belt, and the buoyant evolution of sunspot and the buoyant evolution of sunspot magnetic fieldsmagnetic fields

• Maybe this will help narrow down the Maybe this will help narrow down the range of the forecasted maximum range of the forecasted maximum smoothed sunspot numbersmoothed sunspot number

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Keep an eye on NASA Headline News, Keep an eye on NASA Headline News, http://www.solarcycle24.com, http://www.swpc.noaa.gov, and http://www.solarcycle24.com, http://www.swpc.noaa.gov, and http://spaceweather.comhttp://spaceweather.com

http://science.nasa.gov/science-news/science-at-nasa/http://science.nasa.gov/science-news/science-at-nasa/2011/02mar_spotlesssun/2011/02mar_spotlesssun/

Page 12: Selected Topics in Propagation

ARRL DX CW and PHARRL DX CW and PH

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 5 6 7 8 Feb Mar

It’s headed in the right direction!

ARRL DX CW

ARRL DX PH

Page 13: Selected Topics in Propagation

ARRL DX CW and PHARRL DX CW and PH

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Recent solar activity helped ARRL DX PH the most

ARRL DX CWARRL DX PHred line is one-day running average

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 5 6 7 8 Feb Mar

28 MHz

21 MHz

Page 14: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

The M-FactorThe M-Factor

No, not this M

Page 15: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

What Is The M-Factor?What Is The M-Factor?• The M-Factor (MUF factor) relates the MUF (maximum The M-Factor (MUF factor) relates the MUF (maximum

useable frequency) to the critical frequencyuseable frequency) to the critical frequency– MUF = M-Factor x Critical FrequencyMUF = M-Factor x Critical Frequency– M-Factor and critical frequency (along with other parameters) M-Factor and critical frequency (along with other parameters)

are measured by ionosondesare measured by ionosondes

• M-Factor is one over the sine of the angle between M-Factor is one over the sine of the angle between the ray and the ionosphere the ray and the ionosphere (also known as the secant law as 1/sine (also known as the secant law as 1/sine = secant)= secant)

sine of this angle

If the angle = 90o (vertically incident), then the M-Factor equals 1 and the MUF = the critical frequency

ionosphere

Page 16: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Apply It To The IonosphereApply It To The Ionosphere

ionosphere

Earth

Thus the M-Factor = 1 sine (1o)

= 57

• Wow – if the critical frequency is 5 MHz, then the MUF would be 285 MHzWow – if the critical frequency is 5 MHz, then the MUF would be 285 MHz• But hold on – the Earth-ionosphere system isn’t flat – it’s sphericalBut hold on – the Earth-ionosphere system isn’t flat – it’s spherical

= 1o

Ω = 1o

Page 17: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

The Real Earth-Ionosphere The Real Earth-Ionosphere SystemSystem

ionosphere

Earth

height now matters – let’s assume 300 km

Now the M-Factor = 1 sine (17.5o)

= 3.3

MUF for this F2 region scenario is about 3 times the critical frequency

= 1o

Ω = 17.5o

Page 18: Selected Topics in Propagation

M-Factor vs Height and M-Factor vs Height and AngleAngle

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

This calculation assumes specular (mirror-like) reflection over an infinitely short distance – the real-world is refraction over a spherical distance

height distance ΩM-Factor

100 km 0 deg 2243 km 10.1 deg 5.75 deg 1389 km 11.3 deg 5.110 deg 927 km 14.2 deg 4.125 deg 408 km 26.8 deg 2.2

200 km 0 deg 3152 km 14.2 deg 4.15 deg 2226 km 15.0 deg 3.910 deg 1620 km 17.3 deg 3.425 deg 781 km 28.5 deg 2.1

300km 0 deg 3836 km 17.3 deg 3.45 deg 2877 km 17.9 deg 3.310 deg 2193 km 19.9 deg 2.925 deg 1124 km 30.1 deg 2.0

400 km 0 deg 4401 km 19.8 deg 3.05 deg 3422 km 20.4 deg 2.910 deg 2687 km 22.1 deg 2.725 deg 1412 km 31.4 deg 1.9

The higher the layer, the longer the hop distance for a given angle

But the higher the layer, the lower the M-Factor (lower MUF) for a given angle

Page 19: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Rule of 3 and Rule of 5Rule of 3 and Rule of 5

• For the FFor the F22 region with region with low angleslow angles, the MUF is , the MUF is approximately 3 times the critical frequencyapproximately 3 times the critical frequency– Ionosondes report the M-Factor for a 3000 km Ionosondes report the M-Factor for a 3000 km

hophop• M(3000)F2 or M(D) where D = 3000 kmM(3000)F2 or M(D) where D = 3000 km

• For the E region with For the E region with low angleslow angles, the MUF is , the MUF is approximately 5 times the critical frequencyapproximately 5 times the critical frequency– Close enough for sporadic E, tooClose enough for sporadic E, too

Allows you to estimate the MUF only knowing the critical frequency

Page 20: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Sunspots and Solar FluxSunspots and Solar FluxDuring Cycle 23During Cycle 23

Page 21: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Why Use Smoothed Solar Why Use Smoothed Solar Indices?Indices?

• Reason #1: Daily data (and even monthly mean data) is spiky - Reason #1: Daily data (and even monthly mean data) is spiky - hard to tell what’s happeninghard to tell what’s happening

• Reason #2: The best correlation between what the Sun is doing Reason #2: The best correlation between what the Sun is doing and what the ionosphere is doing is through a smoothed solar and what the ionosphere is doing is through a smoothed solar index - this is the basis on which the statistical model of the index - this is the basis on which the statistical model of the ionosphere for our propagation predictions was developedionosphere for our propagation predictions was developed

Page 22: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Early CorrelationEarly Correlation

y = 0.0009x2 + 0.7278x + 64.11R² = 0.9958

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0 50 100 150 200 250

smoo

thed

10.

7 cm

sol

ar fl

ux

smoothed sunspot number

August 1947 through June 1970(peak of Cycle 18 through maximum of Cycle 20)

Equation from texts on the ionosphere: SF12 = 63.75 + .728 SSN12 + .00089 SSN12

2

(the “12” subscript denotes smoothed values)

Side note - there is very little correlation between daily 10.7 cm solar flux and daily sunspot number

Page 23: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

More DataMore Data

Some more scatter about the trend line, but still pretty good.Some more scatter about the trend line, but still pretty good.

R² = 0.9908

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0 50 100 150 200 250

smoo

thed

10.

7 cm

sol

ar fl

ux

smoothed sunspot number

August 1947 through December 1996(peak of Cycle 18 through end of Cycle 22)

Page 24: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Include Cycle 23Include Cycle 23

• In terms of smoothed sunspot number, second peak is a bit In terms of smoothed sunspot number, second peak is a bit lowerlower

• In terms of smoothed solar flux, second peak is definitely In terms of smoothed solar flux, second peak is definitely higherhigher

• We had much better 6m F2 propagation during the second peakWe had much better 6m F2 propagation during the second peak

R² = 0.9809

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0 50 100 150 200 250

smoo

thed

10.

7 cm

sol

ar fl

ux

smoothed sunspot number

August 1947 through July 2010(peak of Cycle 18 through end of Cycle 23)

0

50

100

150

200

250

valu

e

Cycle 23

smoothed 10.7 cm solar flux smoothed sunspot number

Cycle 23 data

April 2000 Nov 2001

Page 25: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Why The Anomaly?Why The Anomaly?• Dr. Leif Svalgaard (member of the Cycle 24 Prediction Panel) has Dr. Leif Svalgaard (member of the Cycle 24 Prediction Panel) has

several opinionsseveral opinions– The sunspot counting procedure or observers have changed with The sunspot counting procedure or observers have changed with

resulting artificial changes of the sunspot number (as they have in resulting artificial changes of the sunspot number (as they have in the past)the past)

– There are changes in the Sun’s corona or chromosphere accounting There are changes in the Sun’s corona or chromosphere accounting for additional 10.7 cm emissionfor additional 10.7 cm emission

– Penn and Livingston’s observations (Penn, M. J. and W. Livingston, Penn and Livingston’s observations (Penn, M. J. and W. Livingston, Temporal Changes in Sunspot Umbral Magnetic Fields and Temporal Changes in Sunspot Umbral Magnetic Fields and TemperaturesTemperatures, , The Astrophysical JournalThe Astrophysical Journal, 649, L45-L48, 2006 , 649, L45-L48, 2006 September 20) suggest that sunspots have been getting warmer September 20) suggest that sunspots have been getting warmer during the last decade, leading to a decreased contrast with the during the last decade, leading to a decreased contrast with the surrounding photosphere and hence lessened visibility, possibly surrounding photosphere and hence lessened visibility, possibly resulting in an undercount of sunspotsresulting in an undercount of sunspots

• No definite answer (yet!)No definite answer (yet!)• Visit http://www.leif.org/research and select item 1020 for detailsVisit http://www.leif.org/research and select item 1020 for details• Check out my Propagation columns in the forthcoming May 2011 Check out my Propagation columns in the forthcoming May 2011

and June 2011 issues of WorldRadio Online for more on thisand June 2011 issues of WorldRadio Online for more on this– http://www.worldradiomagazine.com/http://www.worldradiomagazine.com/ WRO is free !WRO is free !

Page 26: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Ionosphere-Ionosphere ModesIonosphere-Ionosphere Modes

Page 27: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Multi-Hop Can Have LimitsMulti-Hop Can Have Limits

• On the lower bands there may be too much absorption for multi-On the lower bands there may be too much absorption for multi-hop – the signal is too weakhop – the signal is too weak

• On the higher bands the MUF may not be high enough to refract On the higher bands the MUF may not be high enough to refract the ray back to Earth for multi-hop – the ray goes out into spacethe ray back to Earth for multi-hop – the ray goes out into space

ionosphere

Earth

Page 28: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Higher MUF & Less Higher MUF & Less AbsorptionAbsorption

• Are there modes that Are there modes that couldcould give a give a higher MUF and/or lesser absorption?higher MUF and/or lesser absorption?

• Yes - there appear to be three of Yes - there appear to be three of themthem– Chordal hopChordal hop– DuctDuct– Pedersen RayPedersen Ray

chordal hop unaffected by the ionosphere

in between refraction points

duct consecutive refractionsbetween E and F regions

Pedersen Ray high angle ray, close to MUF,

parallels the Earth

Page 29: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Chordal HopChordal Hop• Example – TEP (trans-equatorial Example – TEP (trans-equatorial

propagation)propagation)K6QXY to ZL on 6mRay trace from Proplab Promonthly median results

• High density of electrons on either side of geomagnetic equatorHigh density of electrons on either side of geomagnetic equator

• Extremely long hop – approximately twice a normal hopExtremely long hop – approximately twice a normal hop

• Only two transits through the absorbing regionOnly two transits through the absorbing region

• No ground reflectionsNo ground reflections

• Literature says MUF is approximately 1.5 times normal F2 hopLiterature says MUF is approximately 1.5 times normal F2 hop

refraction

refraction

helps MUF and absorption

area of higher electron density

area of higher electron density

Page 30: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

DuctDuct• Requires upper and lower boundary for successive refractionsRequires upper and lower boundary for successive refractions

• Need entry and exit criteria - small range of anglesNeed entry and exit criteria - small range of angles

• No transits through the absorbing regionNo transits through the absorbing region

• No ground reflectionsNo ground reflections

• Low grazing angles with ionosphere – higher MUFLow grazing angles with ionosphere – higher MUF

• Believed to allow extremely long distance QSOs on 160mBelieved to allow extremely long distance QSOs on 160m

helps MUF and absorption

Page 31: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Pedersen RayPedersen Ray• Not a lot in the literature Not a lot in the literature

on the Pedersen Rayon the Pedersen Ray• Comment from Comment from Ionospheric Ionospheric

RadioRadio (Davies, 1990) (Davies, 1990)– Across the North Atlantic, Across the North Atlantic,

occurrence tends to peak occurrence tends to peak near noon at the midpointnear noon at the midpoint

• One would surmise that One would surmise that the ionosphere needs to the ionosphere needs to be very stable for a ray to be very stable for a ray to exactly parallel the Earth exactly parallel the Earth for long distancesfor long distances

• Probably no help with MUF Probably no help with MUF – biggest advantage – biggest advantage appears to be with lower appears to be with lower absorption due to less absorption due to less transits of the absorbing transits of the absorbing region and no ground region and no ground reflection lossesreflection losses

helps absorption

• 1 and 2 are “low-angle” 1 and 2 are “low-angle” pathspaths

• 3 is “medium-angle” path3 is “medium-angle” path• 4 and 5 are “high-angle” 4 and 5 are “high-angle”

Pedersen Ray pathsPedersen Ray paths• 6 goes thru the 6 goes thru the

ionosphereionosphere

Page 32: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

A Detailed 20m AnalysisA Detailed 20m Analysis• K2MO (AA2AE at the time) to K2MO (AA2AE at the time) to

ZS5BBO on July 5, 2003 at 1230 ZS5BBO on July 5, 2003 at 1230 UTC on 20m SSB via long pathUTC on 20m SSB via long path

• K2MO reported that ZS5BBO’s K2MO reported that ZS5BBO’s signal was around S7 (~ -83 dBm)signal was around S7 (~ -83 dBm)

• Long path from W2 starts off in daylight, goes into darkness, and ends in daylight

• Short path has high MUF but marginal signal strength due to absorption

• Long path signal strength from ZS Long path signal strength from ZS predicted to be -125 dBmpredicted to be -125 dBm– About 40 dB shy of S7About 40 dB shy of S7

Short path 12,700 kmLong path 27,300 km

Page 33: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

The Ionosphere Along the LPThe Ionosphere Along the LP• Note the tilts in the Note the tilts in the

ionosphere at ionosphere at dawn (W2 end) and dawn (W2 end) and at dusk (ZS end)at dusk (ZS end)

• Tilt can refract the Tilt can refract the ray so that it ray so that it encounters the encounters the ionosphere at more ionosphere at more of a grazing angle of a grazing angle (i.e., a higher MUF)(i.e., a higher MUF)

• Good entry/exit Good entry/exit criteria for ductcriteria for duct

VK5

Page 34: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

Ray Trace from W2 EndRay Trace from W2 End• Proplab Pro can only ray Proplab Pro can only ray

trace out to 20,000 km trace out to 20,000 km (half way around)(half way around)

• Do two ray tracesDo two ray traces– One from W2 end (pictured)One from W2 end (pictured)– One from ZS end (not One from ZS end (not

pictured)pictured)

• Ray trace from ZS end Ray trace from ZS end shows similar ductingshows similar ducting

• Signal strength now Signal strength now estimated to be -89 dBmestimated to be -89 dBm– Close to observed -83 dBmClose to observed -83 dBm

Page 35: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

The Big PictureThe Big Picture• My crude picture on the left My crude picture on the left

shows chordal hops as the shows chordal hops as the ionosphere-ionosphere ionosphere-ionosphere modemode

• Proplab Pro data indicates Proplab Pro data indicates the K2MO-to-ZS5BBO QSO the K2MO-to-ZS5BBO QSO was ductingwas ducting

• Easier to draw chordal hops!Easier to draw chordal hops!

• You’ve probably seen a You’ve probably seen a similar picture in the similar picture in the propagation literature. propagation literature.

Ionosphere-ionosphere modes are our friends

Page 36: Selected Topics in Propagation

PVRC Webinar Mar 9, 2011 K9LAPVRC Webinar Mar 9, 2011 K9LA

SummarySummary• I hope you learned somethingI hope you learned something• This webinar will be on the PVRC web siteThis webinar will be on the PVRC web site

– http://www.pvrc.org/webinar/webinars.htmhttp://www.pvrc.org/webinar/webinars.htm– The slides will also be at The slides will also be at

http://mysite.ncnetwork.net/k9lahttp://mysite.ncnetwork.net/k9la

• Follow-up webinars: More Selected Topics in Follow-up webinars: More Selected Topics in PropagationPropagation– Such as noise, 10m long path, effect of the Moon on HF Such as noise, 10m long path, effect of the Moon on HF

propagation, trans-equatorial propagationpropagation, trans-equatorial propagation

• E-mail me if you have a specific topicE-mail me if you have a specific topic– [email protected]@arrl.net– Also visit http://mysite.ncnetwork.net/k9laAlso visit http://mysite.ncnetwork.net/k9la

• Thanks to Ken K4ZW and to the PVRCThanks to Ken K4ZW and to the PVRC• And now . . . . . . . . . . . Q/AAnd now . . . . . . . . . . . Q/A