regen experts where you at??

Discussion in 'Homebrew and Kit Projects' started by KB2WVO, Oct 28, 2018.

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  1. KB2WVO

    KB2WVO Ham Member QRZ Page

    http://www.vk6fh.com/vk6fh/12au7regen.htm

    link above i did this regen.. i can get com am all day long.. will 700khz to around 1400khz. i try to add to the coil for com am. but it didnt help to get lower to 590khz. local good music station there..
    i can not get it out of the am band. grrrr.. diff coils diff turn count. size. spread out a little tight on form...

    just not gettin it.. i have a coil of wire from a microwave fan. i think it would be in the 30g range. thin thin thread like.. i have some 20 or 22 mag wire. it would be pieced togther for any high count turns..

    ideas what iam doin wrong?

    there is a link on the page to so called build of it.. and it works great it seem.. always that way hey lol .. works for others lol ..

    checked the coil sort of like the one in his image... it is top to bottm 5uh top to tap 3.3uh tap to bottom 2.3uh...

    that should put me in the 5 to 8 mhz range and nothing... no regen at all..
     
    Last edited: Oct 28, 2018
  2. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Well, the source information is vague and contradictory. The first reference has been deleted. The Second shows a coil wound a an unspecified mix ferrite rod, but the accompanying photo shows an unsupported air coil, which doesn't appear to be tapped at the indicated 25% point.

    I don't see any way to give you specific fixes other than ensuring you use an appropriate mix ferrite for below BCB frequency. Part of the charm of regens is experimenting with less than optimum designs and construction. There are dozens and dozens of designs. Keep experimenting and having fun! bill.
     
    KB2WVO likes this.
  3. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    An additional thought. You might consider using the Litz wire of the appropriate size/type for your desired frequency range. Litz wire decreases the skin resistance which affects the coil performance
    .
     
  4. KB2WVO

    KB2WVO Ham Member QRZ Page

    yeah lita be down road. like you said work with try diff things. it is the fun of it for sure.. i been tinkerin with it. but grrr lol once u know coils. there no trick lol. but till then there is a bit of a trick.. i think lol .. black magic lol
     
  5. VK2HHS

    VK2HHS Ham Member QRZ Page

    That unsupported air spaced coil would be an absolute nightmare ...
     
  6. VK2TIL

    VK2TIL Ham Member QRZ Page

    As others have said;

    * The schematic on that link shows an iron or ferrite core (the two dashed lines) and

    * That unsupported air spaced coil would be an absolute nightmare ...

    Wind the coil on a cylindrical form; a toilet-roll cardboard tube was much-used in the old days (and is still a good choice for tinkering) or use a piece of plastic tube.

    Use a calculator such as this;

    http://www.pronine.ca/lcf.htm

    to find the required inductance for a certain frequency (you know the maximum capacitor value and you can guess the minimum at about 15pF for a 365pF maximum).

    Once you have determined the inductance that you require, use a calculator like this;

    http://www.66pacific.com/calculators/coil-inductance-calculator.aspx

    or this;

    https://hamwaves.com/antennas/inductance.html

    to design your inductor. Note that there are quite a few such calculators and they often give different results but they will get you "into the ballpark" for a simple design.

    Inductance can be raised, ie frequency lowered, by inserting a ferrite core into the tube; the best and easiest to obtain is an antenna rod from an old transistor radio (the rods can also be bought new) which is usually #61 ferrite or another maker's version of #61.

    You should be able to "tune" the radio to a lower frequency by slowly moving the rod into the coil.

    Many years ago I used this technique to lower the frequency of my home-made GDO;

    [​IMG]

    The piece of antenna rod, epoxied inside the coil, can be seen here;

    [​IMG]

    Some radios were tuned this way in the old days using a mechanism to slide a core in & out of a coil; it is called permeability tuning.
     
    KB2WVO and VK4FFAB like this.
  7. KB2WVO

    KB2WVO Ham Member QRZ Page

    i have a rod from a old rad shaft SW RX. old side to side dial style.. was junk.. and its just wht i did.. slide inside the coil.. got me down in AM area.. from a pill bottle coil.. il check the links out ty .. lot to learn about coils. i sort of figured more wire lower freq. but wasnt sure. ok off to read up on the links and see how blood shot i can get my eyes tonite lol .. ty for the info..

     
  8. KB2WVO

    KB2WVO Ham Member QRZ Page

    yeah it does suck lol .. i get rite in the 6mhz area. +- 100hz. if that.. its sad..

    not a lot of videos on theroy and building of a regen... tons of built regens and hours of showin them working.. but i hate reading lol always have.. i learn from doing.. but wire is a lot of money to waste lol
     
  9. KB2WVO

    KB2WVO Ham Member QRZ Page

    http://members.iinet.net.au/~cool386/kits/ace.html linked in the orig post above..
    seems to work much better. with antenna side changes..
    got CAM working fairly good. 500hz to around 1450hz. nothing much up there in daytime..

    now to get it on other bands. site is sayin if i read it rite... it is doable by using the caps on antenna.. but not working as of yet..
     
  10. N5WVR

    N5WVR Ham Member QRZ Page

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