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14854Re: AW: AW: [SDRSharp] ebay antenna

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  • MCH
    Jun 24, 2014
      Wish I could find an inexpensive LP antenna for 30-900 MHz...

      Joe M. 

      On Jun 24, 2014, at 6:43 PM, "Ken Alexander k.alexander@... [SDRSharp]" <SDRSharp@...> wrote:

      Speaking of inexpensive scanner antennas, Kent Britain WA5VJB makes several excellent wideband log periodic directional antennas on printed circuit boards.  I have a model that covers continuously from 400 to 1000 MHz.  It costs U.S. $28 and works very well for 4xx and 8xx MHz public service monitoring.  It covers the digital TV bands as well, although I haven't tried it there yet.  It's roughly 12" x 12".   http://www.wa5vjb.com/index.html

      Build it Yourself -- While you're there, you should also visit http://www.wa5vjb.com/references.html and read the article Planar Disk Antennas for Ultra Wideband Applications for a description of an antenna that covers from 144 MHz to 1296 MHz and everything in between.  Read the article then note that if you make the disks a little larger it will work better on frequencies below 144 MHz.  Simple to build.

      Hope people find this of some interest!


      Ken Alexander

      On Tuesday, June 24, 2014 5:38:29 PM, "Ken Alexander k.alexander@... [SDRSharp]" <SDRSharp@...> wrote:

      Seems to me I read somewhere that one of the advantages of silver is that not only is it a good conductor, but the oxide (tarnish) coating that forms is an equally good conductor.  I'm going from memory, so feel free to shoot down this assertion if you know better.  *:) happy

      Gold of course doesn't oxidize.  Another great reason it makes a good contact material.


      Ken Alexander

      On Tuesday, June 24, 2014 5:32:16 PM, "Ken Alexander k.alexander@... [SDRSharp]" <SDRSharp@...> wrote:

      It reminds me of what I have read about the Yaesu ATS-100/120/120A mobile HF antenna.  It has been fairly widely reviewed on eHam.net, almost 300 reviews.  I figure only about 10% of ham equipment owners post reviews on eHam.net...so Yaesu has sold a lot of them at $300+ each.

      People are generally happy with them, but they seem to suffer from reliability problems, so there are a number of low ratings that drag down the average ratings shown on eHam.  Those who haven't had reliability problems love them!

      Interestingly, K0BG a U.S. ham whose main interest is mobile HF operating has built a very comprehensive website on the subject says more than once that the ATS-100/120/120A is the least efficient mobile HF antenna available at any price and that it should be avoided.  Read here:  http://www.k0bg.com/antennas.html.  (Anybody interested in mobile HF operation would do well to spend an evening or two browsing through K0BG's website).

      Moral:  People spend a lot of money on antennas that doesn't work so well (and aren't built so well) made by a company that has the know-how and resources to do much better.  But they're happy with them because a) it's their first mobile antenna and they have nothing to compare it to, or b) it's better than what they had.  Compare that to our EBay seller who may or may not have a good grasp on the theory behind how his scanner antenna works, but sells plenty of them to 600+ satisfied customers.

      Sorry for rambling on like that!  There's a point in there somewhere!


      Ken Alexander

      On Tuesday, June 24, 2014 4:48:11 PM, "'siegfried jackstien' siegfried.jackstien@... [SDRSharp]" <SDRSharp@...> wrote:

      > construction techniques on the Internet, realized they weren't difficult
      > to build and saw an opportunity.

      Yepp ... 27k opportunity :-)

      It probably is better than what he and
      > many of his customers were using before, so his antenna deserves to be
      > called a success.

      If he really sold some pieces of pvc tube with hand-wound coils for that
      money ... yepp success ... as minimum moneywise for him

      Performance on the frequency range??? Who knows what frequency it is built



      Ps you said "I`d wish I thought of it!" ... you still can do better maybe!

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