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Question About Tuning Diodes

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  • nickrumple
    Hi All..... I have a question that I hope someone can help me with. I am planning to build an outdoor remote tuned loop antenna. I have read that you can find
    Message 1 of 6 , Feb 1, 2014
      Hi All..... I have a question that I hope someone can help me with. I am planning to build an outdoor remote tuned loop antenna. I have read that you can find tuning diodes in the range of 40 - 700 pF. Does anyone have any experience with such diodes, and if so, where may I find them. Where I live, there are no electronic parts stores, so I will have to order them. Thanks in advance.


      Nick Rumple
      Kannapolis, North Carolina
    • Chris Trask
      ... I ve done a number of remotely tuned antenna designs and the varactors I like to use have been the MVAM109 and MVAM115. But, those and their direct
      Message 2 of 6 , Feb 2, 2014
        >
        >Hi All..... I have a question that I hope someone can help me with. I am planning to build an outdoor
        >remote tuned loop antenna. I have read that you can find tuning diodes in the range of 40 - 700 pF.
        >Does anyone have any experience with such diodes, and if so, where may I find them. Where I live,
        >there are no electronic parts stores, so I will have to order them. Thanks in advance.
        >

        I've done a number of remotely tuned antenna designs and the varactors I like to use have been the MVAM109 and MVAM115. But, those and their direct replacement, the NTE618, are difficult to obtain and pretty expemsive. The 1SV149 is currently available for a very low price in eBay (#200609638692) and has been used by a number of people as a substitute.


        Chris Trask
        N7ZWY / WDX3HLB
        Senior Member IEEE
        http://www.home.earthlink.net/~christrask/
      • Andy
        Kits and Parts (aka The Toroid King, aka Diz ) sells the MVAM109: http://www.kitsandparts.com/parts.php Andy
        Message 3 of 6 , Feb 2, 2014
          Kits and Parts (aka The Toroid King, aka 'Diz') sells the MVAM109:


          Andy



        • wa4qal
          Hans Summers has a decent writeup on using power diodes and/or LEDs as varicap diodes: http://www.hanssummers.com/varicap.html Dave
          Message 4 of 6 , Feb 3, 2014

            Hans Summers has a decent writeup on using power diodes and/or LEDs as varicap diodes:


            http://www.hanssummers.com/varicap.html


            Dave

          • bubnikv .
            I would not use LEDs as varactors. The LEDs act as photodiodes to some extent, generating noise. It s better to use a zener diode, if you have to. 73, Vojtech
            Message 5 of 6 , Feb 3, 2014
              I would not use LEDs as varactors. The LEDs act as photodiodes to some extent, generating noise.
              It's better to use a zener diode, if you have to.

              73, Vojtech OK1IAK



              On Mon, Feb 3, 2014 at 6:20 PM, <wa4qal@...> wrote:
               

              Hans Summers has a decent writeup on using power diodes and/or LEDs as varicap diodes:


              http://www.hanssummers.com/varicap.html


              Dave


            • n3ikq
              I got mine on eBay. Sometimes you can get 10 MVAN109 tuning diodes for $10 from a guy that goes by username twisttwinkle. Have fun they are fun to use! I got a
              Message 6 of 6 , Feb 10, 2014
                I got mine on eBay. Sometimes you can get 10 MVAN109 tuning diodes for $10 from a guy that goes by username twisttwinkle. Have fun they are fun to use! I got a lot of good info from this link: http://randombio.com/loopantenna.html, I used his design (in pairs) with success. 
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