Checking SWR of LDG Balun with a MFJ-269.

1. 

   signaljunkie says:

   January 12, 2012 at 8:48 PM

   I printed off the specs for this awhile back but never got around to it. I think I will make this a friday night project! Cheers

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2. 

   gccengineering1996 says:

   January 12, 2012 at 7:53 PM

   Good loop antenna there. I would like to learn more about this project. Thanks for showing.

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3. 

   Scotscan says:

   January 12, 2012 at 7:03 PM

   that’s incredible what a signal

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4. 

   boyprodegy says:

   January 12, 2012 at 6:43 PM

   Wish I understood how to make one.

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5. 

   iseemedia says:

   January 12, 2012 at 6:15 PM

   Very mice – I use a similar antenna for SWL.
   Belfast, right? Me too 😀

   Reply
6. 

   MARTINDAVIES756 says:

   January 12, 2012 at 5:49 PM

   I’ve made and sold loads of these and they’re great fun. The standard design I use is to make a 20 inch square of wood 2″ by 1″ and wind 10 turns of enamelled copper wire (usually taken from a TV scanning coil) around it, finally connecting the ends to a 600 – 800 pf tuning cap to complete the loop. Ive made various other sizes to a max of 4 ft square and pulled in lots of stations.

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7. 

   MARTINDAVIES756 says:

   January 12, 2012 at 5:35 PM

   Just to clarify the prev post. A 500pf will not always (in my experience) cover the complete MW band. So usually use a twin ganged cap with 350 & 450 gangs I think and joined the 2 gangs together. These aerials are easy to make. I usually apply varnish to fix the wire to the wooden frame.

   Reply
8. 

   northwestusa says:

   January 12, 2012 at 5:00 PM

   Thanks for the demo! This is sure an interesting antenna. Thank you for putting this up!

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9. 

   XRayCam says:

   January 12, 2012 at 4:12 PM

   Oooow!! Please send me the link to instructions on the LOOP antenna build!! I just paid $345 for a “quantum qx v2.0 plus+” loop antenna with accessories…but not arrived yet. Yours looks like a VERY good build 🙂

   Reply
10. 

    XRayCam says:

    January 12, 2012 at 3:34 PM

    Found your info on first video (build) what sony receiver is that (SW-77)?? I am using a SW-55 for SWL.

    Reply
11. 

    CindyBradyTooh says:

    January 12, 2012 at 3:18 PM

    Wow! GREAT antenna! Very well explained and demonstrated. WELL DONE! 😀

    ~Cindy! 🙂
    ..

    Reply
12. 

    kc7fys says:

    January 12, 2012 at 3:14 PM

    Not bad. I’m going to build my first copper tubing loop antenna. This weekend. Let’s see what happens!

    Reply
13. 

    G0IFI says:

    January 12, 2012 at 2:51 PM

    Is this a passive loop, or do you have a liitle fet preamp circuit or something? I’m looking into loops for lower freq reception due to the horrendous s9+ computer, powerline and ADSL noise pollution round here, anywhere below 5 mhz.

    Reply
14. 

    Strekmann says:

    January 12, 2012 at 2:23 PM

    Oh.. Its not even connected? O.o

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15. 

    sz42781 says:

    January 12, 2012 at 2:03 PM

    could I use a clock radio variable capacitor

    Reply
16. 

    sammyreed says:

    January 12, 2012 at 1:25 PM

    Yeah – AM and Longwave modes use the internal antenna.
    Now this has got me wanting to make a “Navtex antenna” for 518Khz!
    I don’t usually think of myself as savvy enough to make one of those kinds of antennas, but for me, sometimes necessity is the fuel that gets me going and able to get things done.

    Reply
17. 

    Dreamlgider says:

    January 12, 2012 at 12:48 PM

    Nice, it’s útvarp Føroyar 😛
    the transmitter is located at Akraberg
    (61°23’46.12″N 6°41’34.15″W)
    It’s a 200kW transmitter running at 50% usually but cranked up to 100% when the news is on so that ships and boats around the islands hear it.

    Reply
18. 

    NG9D says:

    January 12, 2012 at 11:54 AM

    excellent demonstration. Thanks!
    Lynn, NG9D

    Reply
19. 

    BoshkoIgich says:

    January 12, 2012 at 11:10 AM

    How many turns your loop antenna has? And how many centimeters/milimeters is 2 feet?

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20. 

    yogi540 says:

    January 12, 2012 at 11:08 AM

    @BoshkoIgich 16 turns – 2 feet = 61 cm

    Reply
21. 

    KC8YOQ says:

    January 12, 2012 at 11:06 AM

    @yogi540 Plans please! Great antenna

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22. 

    genesisfan3 says:

    January 12, 2012 at 11:02 AM

    Try ferrite cores. Unless you just enjoy building large things out of wood pieces.

    Reply
23. 

    renekenshin6573 says:

    January 12, 2012 at 10:24 AM

    It almost act’s the same way as a front end except it’s not physically connected to the circuit

    Reply
24. 

    iamIegion says:

    January 12, 2012 at 10:22 AM

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    Reply
25. 

    patchcords says:

    January 12, 2012 at 9:24 AM

    Variable capacitor of 365uf across the coil :-)

    Reply
26. 

    tonytonytee says:

    January 12, 2012 at 9:18 AM

    interesting demo.. thanks n0amy..
    

    Reply
27. 

    mieleman9 says:

    January 12, 2012 at 8:47 AM

    How were the resistors connected on the Balanced side? Were the leads connected or soldered together at the top? His explanation on this is not clear. Thanks for posting this though.

    Reply
28. 

    N7JFP says:

    January 12, 2012 at 8:09 AM

    @mieleman9 I soldered two 100 ohm in series. This gives a resistive load of 200 ohm. The should present about 50 ohms to the MFJ269 analyzer thru the 4:1 balun. 73, N7JFP

    Reply
29. 

    Tritone217 says:

    January 12, 2012 at 8:05 AM

    Not sure exactly what this is testing. The lead length is far too long for a meaningful test, especially on 6m. The reactance values are probably the most interesting thing – which is likely a result of the self-capacitance in the balun, which is more pronounced at higher frequencies.

    There is no look at the choking impedance of the balun.

    The video itself is well done, but not sure of the value of what is presented.

    Reply

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