492 is much closer to one of those 'Free Space' half waves but I have never found one of those for sale nor the material to build one with. With too many variables to properly consider....and those changing with conditions(ground conductivity etc.) Close is usually good enough. I remember when I was happy to get the plate current to dip sharply(couldn't afford one of those fancy wattmeter/swr things) and made lots of contacts all over the place. Who knew? Close enough is definitely good enough, particularly when there are too many variables to count.
492 is the number for the exact 1/2 wave in free space. Actual dipoles are not JUST waves, they are propagating circuits of waves. Hence the 468. Here's how to get the '492' number c=3 x 10^8 m/s 3.281 feet per meter c=3 x 10^8 m/s = Wave (m) x (freq) Hz for 1/2 wave dipole w/o the other effects ---- = 1/2 x 10^-6 x 3.281 (feet/m) x 3 x 10^8 (m/s) = Wave (feet) x freq (MHz) so 1/2 wave in feet = 492 / freq (MHz) This is not 'empirical'.
The thread poster doesn't understand the difference between an empirical approximation accounting for secondary terms, and the scientific method. It's all scientific method. It all comes from, and leads to, understanding through the scientific process.
Interesting discussion here.... And some interesting behaviours in the process. [ * Disclaimer before I start - I do not know Onno well but I know of Onno and he knows of me .... Yes Onno is "better than" a Foundation Class Licensee but chooses to stay at this level as I have been told many times ] I see a number of participants effectively bagging Onno and his communication - and his right to communicate effectively here. Onno is a FOUNDATION-CLASS LICENSEE here in Australia. For those in the US, an Australian Foundation Class License is lower-in-standard than a Technician-Class license (though some here in Oz have used Technicians-Class licenses to get advanced licenses... That's another sad story)... Never bag those on the lowest class of licence grade. Educate and nurture holders not just of these license classes but ALL AMTEURS that hold a license constructively. Remember that AR is there for "self experimentation" and learning under laws in most nations. Some communication presented here demonstrates what I am actively targeting - poor communication and bullying. Everyone is entitled to their view; everyone is entitled to their observations - everyone is entitled to LEARN. Amateurs should be helpers and educators of not just ourselves but the entire community ... we are supposed to be the great communicators. The fact is that we all collectively are the world's worst class of communicators as we all are at war and fight with each other - whether it be those amongst us with high awards and even Nobel Prizes to those amongst us that are heavily disabled... For AR to survive the arrogance - this infighting - this egotism - must cease. And pronto. AR must always be a SAFE PLACE where PEOPLE WANT TO COME/BE in order to grow and survive in this internet age. Its far from this at the moment. Perhaps some here in their wells of self-gratifying arrogance need to re-evaluate their position - and recognise that their pointless contributions are what is really driving AR backwards. There are few activities in AR that can be completed solo in AR. Someone needs to transmit.... another needs to listen. Others also have the capability to join in. There is nothing private about AR. This therefore makes AR a SOCIAL activity. Amateur Radio is about PEOPLE in a Technical, Regulated Environment. Its about learning. So lets be social and helpful of all. Let's be the great educators; lets always remain constructive in our communication with others. Its perhaps time to isolate the trolls and encourage them to take up other activities where they cannot hurt others !
Obviously you want to suppress the opinion of SOME others, while advocating for 'free speech' from those you seem to agree with. That's not a viable model for a "social activity". FYI, all human interactions are "social activity", including this post. We need to address whether it is acceptable to be ignorant of the basics that make ham radio possible. In the US, this is clearly not the case, as that knowledge of the basics is inculcated through the huge pool of test questions that need to be understood in order to pass our exams. It is a more than reasonable point of view to point out the realities of ham radio, at least here in the US: Here, you are exposed and need to know the scientific basics to get a ham license. You are correct that--decades ago-- we in the US could get OTA with extremely little knowledge of the basics, through the entry novice exam. That exam, itself, however, morphed over almost 40 years to become more grounded in the basics. Today, the fact is that US hams THEMSELVES determined the question pool for our entry class--the Technician. It was fellow hams that made the knowledge of such basics a foundation for getting a ham license. That test pool, although IMO burdensome in sheer number, is well within the requirements stated by the mission of Part 97. Advocacy for an absence of knowledge is counter the the reality of getting a US based, Part 97 license. Hams in the US want other incoming hams to have such a knowledge base. And the fact is that we are approaching almost 1,000,000 US Part 97 licensees. So something works, albeit we always , as we should, seek improvement in the process. There are other radio services--such as CB and FRS--which make no such requirements, and their scope is highly limited for just that reason, Not so ham radio, in the US. Do you think this is wrong? I have asked why we are seeing this 'anti-knowledge' advocacy. Please feel free to address that, rather than trying to turn this into some personal attack. IF things are different in Australia, then please tell us how , and why this different approach has been successful, if it has. Thank you. Chip W1YW
Critical thinking skills are, more than at any other point in my lifetime, in desperately short supply.
For me these recent somewhat bizarre podcasts like the OP smack of a resurgence of "anti-intellectualism" which has waxed and waned along with other populist fads. It seems to fit in with the current semi chaotic state of politics worldwide as well. Richard Hoestadter wrote about this back in the early '60s - " In considering the historic tension between access to education and excellence in education, Hofstadter argued that both anti-intellectualism and utilitarianism were consequences, in part, of the democratization of knowledge. Moreover, he saw these themes as historically embedded in America's (and Australia's?) national fabric, an outcome of its colonial European and evangelical Protestant heritage. He contended that Protestantism's anti-intellectual tradition valued the spirit over intellectual rigour." 73, John, WØPV
In 50 years as a Ham, 40 years as an RF Engineer, and 30 years as a scientist... ...I have yet to discover a single valid conflict between the observable reality of the scientific method versus radio equipment and antennas. The Cult of Anti-Observable-Reality is an ancient belief system, now popularized by social media. Its foremost adherents make their case while climbing the flanks of Mt. Stupid, adjacent to the Dunning-Kruger effect zone. It isn't beneficial to pay homage to their tenets of discourse
Bonnie-- 'Mount Stupid'? That not only states the reality but is hilarious! Bonnie is referring, in part, to this link: http://theengineeringmanager.com/growth/mount-stupid/ Now Bonnie is not saying that anyone here is stupid: Bonnie obviously is more than capable of speaking for herself--but my take-away is that we see too many people embracing too little knowledge, with too little critical thinking as process. This, at a time that more people have some elevated level of education than at any time in history. Look: I am not advocating any sort of dissing of Onno. What I am saying is that we are seeing a point of view essentially advocated through 'front page' news, which is not consistent with who we, as hams, are in the US. I am obviously a bit frustrated, because I have been more than patient in correcting that position previously, yet we continue to see more of it. It's not dissing and its not anti-social. Its exhortation to 'think things through'---being ignored. Now, if you think that expressing ignorance is OK, I certainly agree with you. But ignoring correction is bordering on the realm of belief. Or fantasy. Both are dangerous as portrayals of the universe of reality.
The Cult of Anti-Observable-Reality's key belief system has gone viral recently, driven by Social Media algorithms engineered for clicks-not-facts. The core disciples of the cult remain perhaps less than 25% of the general population; but, they are supported by an additional 15%~20% in temporary power-sharing alliances. Ham radio really has a triple-faceted existence: Technical: Science-Invention-Engineering Hobby: Competition-Collecting-Appliance Operating Social: Club Networking-Social Media Hams who care about the 1st facet (Technical) should speak up to resist those efforts from the 3rd facet (Social) which promote clicks-not-facts in the Amateur Radio Service. .
Chip, Gee some are misguided ! The "Freedom of Speech" argument - the prime defensive cry and rally of the BULLY. For the record, I am a huge supporter of free speech - yet I am also a huge supporter of ensuring that there are also community and interest group standards in place that respect all. That is where regulation comes in. Some term regulation restriction of free speech … that is crap... its attitudes to maintain decorum. Yet within the freedom of speech argument comes decorum and acceptable behaviour. See that is where the whole right that some nations have to free speech in-law argument falls flat - common decency and basic human rights and standards and the right to defame and defile others is promoted and encouraged by law. Oh you can get your justice in courts, if you can prove it, but then the only winner is the Lawyer and Tesla - who lawyers purchase their cars off !!! Only the bully usually has the resources (i.e. the psych bent to have no feelings towards others) to deal with defamation... Standards internationally in AR have gone out the door... just look at "pile ups" on HF and some of the comments you hear on repeaters... some linked internationally ! Remember that some of these comments, even just heard by some of our community in some nations, can lead to imprisonment ! Hence the extreme need for standards and decorum. Some also state heavily that picking up and correcting ignorance is important. I stated clearly that guidance and support is the way to cure ignorance - not bullying and attack. There are soooo many myths in AR (i.e. some of the statements that prompted this thread, concepts such as "off centre fed dipole" … the usual statements/comments etc...) - and the only way we get rid of these "common misguided acceptances" is by guidance through effective communication. HAM - Help All Mankind. Communication. We must all make AR an inclusive, inviting place where people WANT to follow our leadership roles and want to be involved with all of us - especially our ladies, partners, children, grandchildren, nieces, nephews etc. . That is our future. At the moment comments that we see here and in many other places clearly demonstrate the "cigar smoking" attitudes of "glory days gone past" … supplemented today with internet-based "trolling". Such behaviours have led many in the community to see AR as an irrelevant grumpy-old-man's ego pit ! And or those who also put percentages on the social aspect or look at clubs etc. as the element... Crap. Remember, for communication someone needs to transmit and someone needs to receive. Otherwise what is the point? AR is about Communication - whether you be a club member or just a HAM sitting at home. That makes our activity 100% social and all other activities around this supporting social conducts. Being social means people and respect of people (and their feelings ... even if misguided) involved with our activity first; respect of people and their differing views is paramount. Steve I VK3VM / VK3SIR Grumpy Old Man when it comes to Arrogance and poor people behaviour !
Complete Clap-trap ! Demonstrative of the old glory-days "cigar smoking" attitudes that some hold in AR. This looks one inch in front of one's nose at one's self interests. Now lets look a couple of miles down the road ... and into the collective good and future? How does AR survive? The people focus; making AR a place that people want to come to. That is fully within all our interests … more people to talk with … more DXCC entities …. More importantly … more in our activity, making us more significant to the community and thus making it harder for the community that wants to sell off our resources (i.e. spectrum allocations) to business interests. Look at the BIG Picture ...
Vitriolic attack. Instead of addressing my sincere and reasonable questions (on Australian hams), you attack me, again. This time with an off-topic discursive diatribe. Then pretend that my 'opinion' is unique and that I am a sole, bad, person, while you ignore others' educated comments along my same lines. So let me ask again, in another way: does Australia have a 'starter' ham license that does not require basic technical knowledge in order to get a callsign? Note that I am "expressing my ignorance" on this matter--and asking you, cordially, for information. Ham radio is a technically oriented activity which requires a mastery of simple scientific and applied basics for the privilege of world- wide communication ability. That is my understanding of what international telecom treaties define. Am I wrong? Some may wish to stop there on the technical end, but all are encouraged to learn more, and have fun in the process. The premise under which we all undertake this enterprise-- a mastery of basics-- should never, ever, be abandoned nor trivialized. Nope. Not goin after your 'comments'. Not happening. Best to you in this new year. 73 Chip W1YW
