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Locked Question About Tuning Diodes

 

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
 


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
 

Kits and Parts (aka The Toroid King, aka 'Diz') sells the MVAM109:



Andy
[email protected]
 

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


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


Dave
 

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:



Dave
 

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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