I think the multi-wire T top-hat was to add sufficient bandwidth so the operator could operate at not just 1.5 MHz, but also below. The 1.5 MHz is probably just an indication of the 'maximum' frequency of the station. There was no real legal limitation on the frequencies available to amateur radio experimenters until the Communications Act of 1934.
My understanding is that the (non-radiating btw) horizontal T-hat wires serve to force more current into the too-short-for-resonance vertical radiator in applications where it would be impractical to have a full quarter-wave vertical due to the very long wavelength. This makes the short vertical radiate "brighter" than it would otherwise.
I will like to have permission to share some of the knowledge I gained from here with my colleagues this weekend at national guard drill. I will be giving special thanks to Dr. Erikson and MIT .
Hi Sam - this is way late (just saw your comment), but these are available here on YT precisely so the information can be shared. Drop a comment here on how you ended up using the material. Thanks for the interest.
Great lecture, I am interested in shortwave radio and propagation of HF radio waves. This helps understand the science behind the fascinating world of world radio.
I continue to LEARN = There are so many things I DON'T KNOW... Thanks for this LECTURE. Microwave Training Institute, a school now 'defunct', owned by ALAN SCOTT, I learned all this STUFF in 1985 in Mountain View, California in 9 MONTHS: taught by working Physicists and Engineers in the SILICON Valley: Klystrons, Magnetrons, TWT's, YIG resonators, use of spectrum analyzers, vector network analyzers, microwave transistor circuits, low noise amplifier design lecture/microwave amplifiers 4-18 GHZ, practical use of the SMITH CHART, normalizing impedance, Admittance/Impedance, VSWR, Reflection coefficient and laboratory work. SHUNT and SERIES LC MATCHING and RADAR BASICS = We graduated to become COMPETENT Microwave Electronics Technicians readily to be employed by the industry.... kTB, Boltzmann constant... etc... etc...
I like it. do anyone let me know what kind of effects we see during 846 kHz medium wave propagation through 35 meter antenna. How our signal respond to bad weather like storms and heavy rain and lightening.
Index of near earth atmosphere is very close to unity. In the presence of plasma (equal distribution of positive and negative charge) the refractive index will drop below 1, depending on the frequency of the electromagnetic wave. This is the optics of metals as described in Born & Wolf. The radio wave is reflecting from what it perceives as a metallic layer. One slide in the presentation correctly identifies this as total internal reflection as occurs in an optical fiber, but I don't believe it is correct to characterize this as refraction -- at least not from the perspective of ray tracing and classical optics.
@@fredriko.zachrisson9711 Thanks for your interest. Geospace != ionosphere. The ionosphere refers to the charged portion of the upper atmosphere. Geospace refers to the larger set of processes occurring in near-Earth space, such as those farther out in the magnetosphere (portion of space where Earth's background magnetic field is a dominant force; plasma densities are very low compared to the ionosphere). So the names are not describing the same region, and are appropriate.
Loving the candid discussion of video and funding issues in the intro
I feel so fortunate to be able to watch this lecture! Thank u!
I think the multi-wire T top-hat was to add sufficient bandwidth so the operator could operate at not just 1.5 MHz, but also below. The 1.5 MHz is probably just an indication of the 'maximum' frequency of the station. There was no real legal limitation on the frequencies available to amateur radio experimenters until the Communications Act of 1934.
My understanding is that the (non-radiating btw) horizontal T-hat wires serve to force more current into the too-short-for-resonance vertical radiator in applications where it would be impractical to have a full quarter-wave vertical due to the very long wavelength. This makes the short vertical radiate "brighter" than it would otherwise.
Solar cycles are badass, never imagined the Sun's magnetic poles were flipping every 22 years, I knew of Sun's "seasons" but that blew me .
Very nice
I will like to have permission to share some of the knowledge I gained from here with my colleagues this weekend at national guard drill. I will be giving special thanks to Dr. Erikson and MIT .
Hi Sam - this is way late (just saw your comment), but these are available here on YT precisely so the information can be shared. Drop a comment here on how you ended up using the material. Thanks for the interest.
The best explanation of propagation on the web!
‘So we can’t record it in arbitrary resolution” 🤪🤪🤨
Great lecture, I am interested in shortwave radio and propagation of HF radio waves. This helps understand the science behind the fascinating world of world radio.
Fascinating lecture
I continue to LEARN = There are so many things I DON'T KNOW... Thanks for this LECTURE.
Microwave Training Institute, a school now 'defunct', owned by ALAN SCOTT, I learned all this STUFF in 1985 in Mountain View, California in 9 MONTHS: taught by working Physicists and Engineers in the SILICON Valley: Klystrons, Magnetrons, TWT's, YIG resonators, use of spectrum analyzers, vector network analyzers, microwave transistor circuits, low noise amplifier design lecture/microwave amplifiers 4-18 GHZ, practical use of the SMITH CHART, normalizing impedance, Admittance/Impedance, VSWR, Reflection coefficient and laboratory work. SHUNT and SERIES LC MATCHING and RADAR BASICS = We graduated to become COMPETENT Microwave Electronics Technicians readily to be employed by the industry.... kTB, Boltzmann constant... etc... etc...
What is it that gives the sun its 11 year cycle?
Fascinating lecture!
I like it. do anyone let me know what kind of effects we see during 846 kHz medium wave propagation through 35 meter antenna. How our signal respond to bad weather like storms and heavy rain and lightening.
Index of near earth atmosphere is very close to unity. In the presence of plasma (equal distribution of positive and negative charge) the refractive index will drop below 1, depending on the frequency of the electromagnetic wave. This is the optics of metals as described in Born & Wolf. The radio wave is reflecting from what it perceives as a metallic layer. One slide in the presentation correctly identifies this as total internal reflection as occurs in an optical fiber, but I don't believe it is correct to characterize this as refraction -- at least not from the perspective of ray tracing and classical optics.
I don't think the Soviet union was too happy with that ship broadcasting the Voice of America.
The medium changes the message. (5:30,1:10:30)
51:00 Ionosphere.
Great lecture!
Do you think ufos are recharging energy from the atmosphere
Moralim bozuluyor şunları gördükçe.
I'm one of the 12 people who is watching!
Why 4 people dislike this?
I bet 1 of them was my wife.
Frank W3LPL knows thats the correction on Marconi because he was there LOL :)
Geospace vs ionosphere? That's my biggest pet peeve with academia, always picking a new name for something that already has a perfectly good name.
100% agree.
@@fredriko.zachrisson9711 Thanks for your interest. Geospace != ionosphere. The ionosphere refers to the charged portion of the upper atmosphere. Geospace refers to the larger set of processes occurring in near-Earth space, such as those farther out in the magnetosphere (portion of space where Earth's background magnetic field is a dominant force; plasma densities are very low compared to the ionosphere). So the names are not describing the same region, and are appropriate.
I-on-no-sphere
only 142 likes and 2 thumbs down?! but mnm sold a million albums?! geesh!! haha
I need a friend who is vast in ionospheric physics who can help me become better.... I'm from Nigeria
Hello)
Would the guy that keeps interupting the speaker, please shut up.
The whole cold war was just to cover up ionosphere research lol
Great lecture, but those soy boys in the beginning😝
Is that Jim Jefferies?
Great lecture!