Understanding HF Propagation

[@BryanWicks]

This presentation should be incorporated into the initial training of anyone wishing to get their ham license. I found the information to be concise, articulated well, sufficiently illustrated, and no needless fluff. Anyone actively interested in the topic will be well served with this introduction into the concepts discussed. Thank you for uploading this video; I only wished that I had seen it much sooner!

[@pauldenisowski]

Thank you!

[@y_x2]

Yes but at a much lower speed.

[@solarmfolijezastakla]

No matter which ham radio class you are and how much experience you have this video should be listened many times.

[@TheTechPrepper]

What a wonderfully executed overview of HF propagation. I wish I had seen this video while studying for my General license. Clear, concise and pure gold.

[@outwithradios8145]

after 44 years of HF ops it still makes me feel like a child when i get long DX,what a great feeling

[@TylerWilson-f9t]

Wow, it's really good. It's very attractive and the AD is very interesting

[@DoronTirkel]

Anyone who is seriously interested in the subject will benefit from this introduction to the concepts covered. The information is articulated and illustrated clearly. Doron, 4X4XM

[@pauldenisowski]

Thank you for the feedback!

[@gbisaga]

I agree with the other folks, if you are studying for a FCC ham exam, especially the General or Extra exam, you should watch this video. Good concise description that will supplement your other learning.

[@elmoreglidingclub3030]

This is an absolutely excellent explanation and presentation. THANK YOU!

[@pauldenisowski]

Thank you for the feedback!

[@redsky1433]

Excellent presentation. Clear and to the point. The details of HF propagation can get quite complicated but this introduction is spot on.

[@pauldenisowski]

Thank you!

[@muhammadsoleh9148]

Good English presentation...

[@pauldenisowski]

Thanks - it's my native language :)

[@victorb22622]

Very nicely described.refrashed my knowledge of hf prepogation

[@pauldenisowski]

Thank you!

[@m_rehanbutt]

I luckily trained from R&S Germany

[@garylanders1470]

Great presentation! Thank you kindly

[@jamespruitt1046]

Does the day vs. night rule apply to the time of day for the location of the receive / transmit antennas or the location of the person you're trying to communicate with? Meaning if my antenna is in Hawaii and it's morning, but I'm trying to communicate with someone in Guam, would I use a frequency based on the time in Guam or the time in Hawaii?

[@Ambatukamhorifooq]

Amazing presentation, thank you!

[@pauldenisowski]

Thanks!

[@m_rehanbutt]

Good Presentation

[@rfmonkey4942]

"HF the only way to fly" regards from vk3 and remember "when triodes are glowing electrons are flowing"

[@chrismeagher7237]

Excellent presentation with simple, effective graphics. Thanks

[@pauldenisowski]

Thanks for the feedback!

[@GraceKataliko]

You're the best 👍👏👏👏

[@lpark8]

Wow. Great presentation. It covers a lot of ground. I’m gonna have to listen to it again. Thank you!

[@Brigantine2008]

Great video, thank you🇺🇸

[@pauldenisowski]

Thank you for watching!

[@drankurbaruah]

How was sun spot info collected 400 years ago? Thanks for the awesome video. Learnt a lot. 🙏

[@pauldenisowski]

Visual observation. There are actually some manuscripts from that time that show sunspots being recorded (see image at link below, from the year 1611). Not sure that they followed the modern precautions /warning regarding looking at the sun. :) Thanks! images.skinnerinc.com/full/920/1217920_view%2016_16.jpg

[@drankurbaruah]

@@pauldenisowski Damn that is interesting!!! Thank you so much!!!

[@G0FUW]

One of my students pointed out that the statement at 10:43 says that when the RF passes through the ionosphere and into space, that is the critical frequency. However, all the textbooks I have say the critical frequency is the highest frequency that is reflected (refracted) back to ground. Is there another definition in use?

[@pauldenisowski]

That's a great question. I suppose you could avoid ambiguity by defining it as the frequency above which signals pass into space and below which signals are refracted back (laughs).

[@tixilx]

Critical frequency is the highest magnitude of frequency above which the waves penetrate the ionosphere and below which the waves are reflected back from the ionosphere. It is denoted by "fc". Its value is not fixed and it depends upon the electron density of the ionosphere.

[@G0FUW]

@@tixilx that was my understanding too.

[@elkierose6228]

How do you prevent HF signals.

[@kartiniganesha6741]

In maximum condition, how must the most longer distance range for communication in HF frequency?

[@pauldenisowski]

HF can be (and regularly is) used to communicate between any two points on the globe, so maximum range is half the Earth's circumference :) In practice, the maximum achievable distance is function of many factors, including the current state of the ionosphere, the chosen frequency, the Tx and RX antenna characteristics and orientation, the Tx power, the Rx sensitivity, noise levels, modulation type, etc. During peaks in the 11 year solar cycle, worldwide communication can often be accomplished with less than a watt of power and a very modest antenna, whereas at the "troughs," it can be very challenging to reach certain stations without very high power levels and very good antennas.

[@WW5RM]

@@pauldenisowski slightly more than half as the RF horizon is more than visual horizon. Radio waves bend. Plus multi hop and long path happen daily. Many factors can give more range than just half. WW5RM

[@WW5RM]

My furthest QSO is 9100 miles / 14,650 km. Jan - ZS6HA in South Africa. I am in Texas. WW5RM

[@pauldenisowski]

​@@WW5RM Yes, of course. :) Long-path is an excellent example of where the total path length will be longer than the "short part" to the destination: There are many occasions where or reasons why long-path may be the best way to reach a given station. And as you also point out, the actual path length will depends on the number of hops, etc. I interpreted the question to be: "what is the max possible distance between transmitter and receiver when using HF?" and since HF does allow (under the right conditions) communications between any two points on the globe, my somewhat tongue-in-cheek answer was "half the Earth's circumference" :) Thanks for pointing out that the actual max propagation distance can be considerably longer. 73!

[@pauldenisowski]

@@WW5RM Impressive! The long path between EM23 and KG53 would be about 15,800 miles :)

[@philmonat9352]

Very Good !

[@skydivingcomrade1648]

Great video

[@richardweir5497]

question about slide 23. you stated if the MUF becomes higher than the LUF @17:38. did you mean if the LUF becomes higher than the MUF??

[@Network_ned]

I was wonder the same because “

[@philsimpson6093]

Excellent presentation

[@boim9312]

Great explanation 🥳

[@abundantharmony]

I wonder if there are any flat Earth radio people out there...

[@konnorkuznetsov1035]

Excellent presentation! This is perfect for my new ham friends, thank you!

[@storaman12]

Excellent

[@bijohnAdams]

It is informative indeed... Thanks...

[@RogerBravo12]

Really good presentation 👏🏼 so kind of R&S to set up this videos of how radio and some antennas works. Sended this video to some friends that are interested in radio 💪🏼 Best 73/ Roger

[@pauldenisowski]

Thanks! In addition to test and measurement instruments, we also design and manufacture HF radios, amplifiers, antennas, etc. (although mostly for the commercial and military / government markets, not really for amateurs). Thanks again for the feedback! 73, Paul KO4LZ

[@RogerBravo12]

@@pauldenisowski Nice to hear 😀 I have the privilege to use some R&S instruments in my work 👍🏻 de Sa1ckr

[@2ysur]

Well done.

[@raghumehra4949]

Anda boleh memilih untuk salah satu daripada hadiah di atas

[@pauldenisowski]

Pemberian ilmu adalah anugerah terhebat :)

[@rippin187]

Send this to people who think the earth is flat. Prepare to be amazed by their ignorant defiance.

[@pauldenisowski]

If the world were flat, there would be no long-path propagation :)

[@tonyturtle5805]

the picture depicts lines of electromagnetic force but they tend to make our mins believe the signals are shot out like bullets,but its really a giant omni directionals disruption of molecules from the antenna envoping in an omni directional patteren like a bomb going off,the molecule stays put but transfers the vibration to the nieghboring molecule like dominoes,f going deep into the ground and reflecting back upwards or refracting from the ground becuase of the different meduim opposedt to the atmosphere then reaching up into the inonsphere where it then refracts back to earth where it could end up anywhere there is a least resistant path to do so ,i think anyway ,every time we hit the key we ignite a giant vibration of the molecules like a pattern of an explosion ,with everything staying put

[@RichardKCollins]

Maybe you should make a video to share this particular vision of how things work. The words are not quite enough.

[@LawsonIris-u9f]

Hernandez Shirley Smith Cynthia Perez William

[@TinishaBurden-d3b]

Nikolaus Lodge

[@Hiujh-f5m]

Garcia Brian Anderson Sharon Miller Richard

[@RichCasey]

Thanks for a great presentation! Will pass along to other ham operators. N5CSU

[@Rohde-Schwarz]

Hi Rich, thanks for the recommendation.

[@pauldenisowski]

Thanks Rich! 73 de Paul, KO4LZ

[@WillieMorrison-o7u]

Tessie Crossroad

[@agonizedanguish6267]

Giggity giggity Recon

[@mariasaatcheson8843]

Miller Joseph Williams Barbara Gonzalez Donald

[@GildaMills-i9q]

Thad Spring

[@AlexanderTolley-j9y]

Von Station

[@KennethJones-k1y]

Moshe Gardens

[@ShelleyAlger-o1e]

Libbie Summit

[@NettieRodriguez-r2y]

Hall Daniel Lopez Sandra White Margaret

[@EsmeContreras-x1s]

Wow, it's really good. It's very attractive and the AD is very interesting

[@LitzyHutchinson]

Wow, it's really good. It's very attractive and the AD is very interesting

[@LitzyHutchinson]

Wow, it's really good. It's very attractive and the AD is very interesting

[@MiaWilson-i5o]

Wow, it's really good. It's very attractive and the AD is very interesting