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Loop On Ground Antenna

Discussion in 'Amateur Radio News' started by KD5W, Jul 18, 2021.

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  1. AA4MB

    AA4MB XML Subscriber QRZ Page

    Yet: "DXpedition ops have told me Im often 10 dB+ above the pileups and Im in the log on the first call." It's hard not to believe all the modeling software and such - but real world results seem to have given KM1H's inverted vee the nod for long distance as well.
    M1WML and UT7UX like this.
  2. KM1H

    KM1H Ham Member QRZ Page

    Modeling software doesnt take ducts or various propagation related path distortions into consideration. A duct has low attenuation no matter what band including VHF/UHF.

    Several thought I was running 10KW or more and several YCCC members showed up unexpectedly over the years to catch me at it.
    M1WML likes this.
  3. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Antenna modeling software is not intended to take ANY propagation into consideration.
    M1WML, UT7UX, MW1CFN and 1 other person like this.
  4. KM1H

    KM1H Ham Member QRZ Page

    I have no idea what the VSWR is, the wire was cut to formula, fed in the center with coax and the amp pi network was tweaked to work into it. I do not believe in external antenna tuners when the amps pi network is already an impedance matching device. Additional feedline loss on 160 was ignored.
    M1WML and UT7UX like this.
  5. KM1H

    KM1H Ham Member QRZ Page

    No kidding but some act as if it is the last word.
    N1IPU, M1WML and MW1CFN like this.
  6. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    It IS the last word in describing how an antenna performs i.e. pattern and gain.

    Input the figures from the antenna modeling software into a Propagation Modeler for propagation estimating.
    M1WML likes this.
  7. KM1H

    KM1H Ham Member QRZ Page

    Only when the physical location agrees with the software assumptions. You can import/export all sorts of things to better understand a particular situation but I have no interest in counting leaves or raindrops for 160M.

    Build it and use it with a minimum of fuss.
    N1IPU, M1WML and WN1MB like this.
  8. W1YW

    W1YW Ham Member QRZ Page

    One should never keep one's mind so open that your brains fall out.

    The LOG is a poor antenna. It is a poor antenna because it is placed in the extreme nearfield of lossy ground, which invokes the transmission line effect and thereby produces substantial phase canceIlation.

    That is not a question of being open or closed minded, It is a physical explanation as to why the performance is poor.

    Have a great day:)

    Chip W1YW
    KR3DX, M1WML and AD5HR like this.
  9. W1YW

    W1YW Ham Member QRZ Page

    1) that company is out of business;

    2) The cited patent---US 4825224-- actually states that the efficiency of the antenna will be poor and recommends increasing performance by RAISING the ELPA (Eyring) ANTENNA OFF THE GROUND-- by means of stakes. Even shows a figure to represent that.

    Read the patent to see for yourself.

    Why did they recommend 'raising the antenna off the ground'? Because that diminishes the transmission line effect's phase cancellation, thereby enhancing the efficiency.
    Last edited: Jul 24, 2021
    M1WML likes this.
  10. W1YW

    W1YW Ham Member QRZ Page

    I found the assertion (by the Brit here) that my--alleged-- "narrowness of mind puts the U.S. to shame" a better attempt at insult.

    Last edited: Jul 24, 2021
    M1WML likes this.
  11. WN1MB

    WN1MB Ham Member QRZ Page

    Thanks for reporting that and not being bashful with the red text characters and font size enhancement. Stylish! The amateur radio world is forever in your debt for donning the Captain Obvious leotard and cape to deliver a paraphrasing of the age old suggestion of "as high and in the clear as possible" when it comes to antennas.
    M1WML and KC2G like this.
  12. MW1CFN

    MW1CFN Ham Member QRZ Page

    Welsh. I'm Welsh. Or Dutch/Polish, if you prefer ethnicities. Sorry your insular worldview hasn't helped on this occasion. And made you appear a little bit racist, to boot.

    Oh, and you appear to have gone off topic in the manner you previously asserted was "important" didn't happen.

    M1WML likes this.
  13. MW1CFN

    MW1CFN Ham Member QRZ Page

    How about ground gain? It's not very often I find plots by the excellent HFTA shown in antenna model discussions (arguments!) Ground slope also seems to be irrelevant to most modellers, but not to those using antennas in the real world.

    Both are very important in the final consideration of antenna performance, because we all (bar a few in low Earth orbit) have ground to put up with, and even gain from. And we don't all live on a desert mesa, where many modellers seem to spend their spare time, fiddling.
    M1WML likes this.
  14. PA0MHS

    PA0MHS Ham Member QRZ Page

    Soft crimping?
    M1WML likes this.
  15. UT7UX

    UT7UX Premium Subscriber QRZ Page

    QRO is the thing that far not easy to deal with as some enviers may suppose. To deliver some 10kW to antenna one needs some 20kW from supply. Plate voltage depends on tube, sure, but we’re talking about up to ten kilovolts so plate transformer, entire isolation, and variable capacitors could not be taken from old TV parts. Even feedline is not easy deal due high voltage and current. And every RFI-related problem becomes much harder to solve. So in fact it is harder to work DX with 10kW than with legal power: obviously the more is power the better are chances to be heard over pileup and QRO stations have their tickets in the first row by default but the more is power the harder is build and manage it.

    They seem just envy. :D When someone has good results especially on the top band this person immediately becomes suspected in illegal power. This is probably because so few hams may build decent antennas for top band so QRO is the only chance to be heard for most of them.
    M1WML, KM1H and MW1CFN like this.

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