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#11
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Not much of an antenna per Cebik
BTW, bought the "Vhf" collection from Cebik
and the model eznec files are pretty good! Would recommend them, BUT be awa SOME will NOT work as downloaded (as ELNEC/EZNEC is limited to 500 segments). At least one had over 1000 segments! be sure to reduce these segments IN SAME (or similar) amounts, until they are under 500 segments (right hand column) total! then they run fine! A very interesting collection of antenna files and worth every penny! As info, Jim NN7K Irv, you are correct when you stated it was a big site! I spent a lot of time reading readers comments until my eyes glazed over. It was like reading every quabble from our own archives for the last twenty years. I think I will have to read the Cebik articles for myself and trace it down that way which will be much more educating. I am glad however that I used the word "atributed" rather than stating it as a fact. I will continue with this progect Regards Art |
#12
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Not much of an antenna per Cebik
Jim - NN7K wrote:
BTW, bought the "Vhf" collection from Cebik and the model eznec files are pretty good! Would recommend them, BUT be awa SOME will NOT work as downloaded (as ELNEC/EZNEC is limited to 500 segments). At least one had over 1000 segments! be sure to reduce these segments IN SAME (or similar) amounts, until they are under 500 segments (right hand column) total! then they run fine! A very interesting collection of antenna files and worth every penny! As info, Jim NN7K EZNEC+ allows 1500 segments. Roy Lewallen, W7EL |
#13
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Not much of an antenna per Cebik
how many s-units more exseptional gain does your v have compared to my
dipole at 20 feet? On May 30, 9:02 am, art wrote: I read a comment attributed to Cebik where he stated that any antenna that is not 1/4, 5/8, 1/2 or 1 wave length is not much of an antenna ! This is a false statement especially when one considers an antenna element based on 1 WL. This antenna is widely used and well described in all antenna books. I have modelled a similar arrangement in Gaussian form where the elements are bent into a Vee shaped like yagi with elements extremely close together where it provides exceptional gain and pattern and can be related visually to a bent long boom but without elements. A planar antenna can also be made with a similar length of radiator with a variable resonator that makes it applicable to a continuous10 thru 20 antenna wherein the resonator serves as a radiating portion instead of the normal coax stub. Also ideal for S.W. listeners on intervening frequencies.( See Cecil's antenna page which uses variable stub lengths instead of a variable resonator) Seems like a lot of mis information is being given out with respect to antennas apparently with the silent agreement of perceived antenna experts and where caustic opinions out weigh technical content . Regards Art |
#14
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Not much of an antenna per Cebik
Richard Clark, KB7QHC wrote:
"Sonething of a parasitic half Rhombic (or parasitic V)". Yes, but the rhombic or Vee antenna usually needs sides which are wavelengths long to produce significant gain. I don`t know what Art has proposed. The TV antenna on the roof near me looks like a Yagi with its elements all bent to the same angle with the boom. Their lengths aren`t multiwavelength even at 200 MHz. Maybe at UHF? VHF gain would depend on phasing between the reflector and the driven element, and the multiple directors and the driven element. Thus its performance would begin with its similarity with the straight Yagi, I`d wager. Before cable and satellite were available, many configurations were tried for TV. Some were sold more on appearance than performance. It`s tough to cover a 4 to 1 frequency range smoothly, but they tried. Some produced decent pictures at some distance from the transmitters over many VHF channels. Amazing! Best regards, Richard Harrison, KB5WZI |
#15
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Not much of an antenna per Cebik
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