Chameleon DIY Magnetic Loop Starter kit First Build

Discussion in 'Amateur Radio News' started by OH8STN, Feb 19, 2017.

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  1. OH8STN

    OH8STN Ham Member QRZ Page

    Hello operators
    starter-kit.jpg For those interested in the DIY Magnetic Loop Starter Kit from Chameleon, this is my first build video using that kit. The video details two different models of a man portable magnetic loop antenna.
    • The first is a 40-10M single turn loop based on the Chameleon P-LOOP.
    • The second is a 80, 60, 40M, double turn loop with switched capacitor to quickly convert between 80, 60, 40M and 40-10M.
    You can watch the video here.


    Amongst my build goals was a desire to build a practical field deployable magnetic loop antenna, which would fit easily into my skipulk or backpack. I certainly could have build a larger more efficient system, but only at the expense of mobility. The design is heavily based on aspects of the Chameleon P-LOOP and Alexloop man-portable loops.

    I hope my video helps other beginners get started with their Chameleon Magnetic Loop starter kit, and would love to see builds from other operators who have also chosen to use this starter kit.

    73 de oh8stn
     
    W5KV, AA8GK, N4GST and 5 others like this.
  2. K5TED

    K5TED Ham Member QRZ Page

    You paid $99 plus shipping for a $20 capacitor, some UHF connectors and a piece of feedline.
     
    AD5KO likes this.
  3. VA7UO

    VA7UO Ham Member QRZ Page

    Yeah that's it be condescending and rude.. What is wrong with you?
    Maybe he is getting into the radio side of things on HF..Myself, V/U and microwaves, it's comments like yours that throw people off.
     
    N1PRH, AA8GK, N4GST and 8 others like this.
  4. VA6ERO

    VA6ERO Ham Member QRZ Page

    nice guy shows how to assemble loop and grumpy old ham jumps on him.
    sure hate to have k5ted,s life.not too good i think??
     
    N4GST, K0PIR and OH8STN like this.
  5. K7LZR

    K7LZR Ham Member QRZ Page

    Very good, and perhaps this will inspire some folks to try their hand at building a small loop :).
     
    N1PRH, K3RW, AA8GK and 2 others like this.
  6. F4HPX

    F4HPX XML Subscriber QRZ Page

    if this costs 99$ it's still more interesting than finished product Chameleon is selling and you have some fun bulding it and understanding how this is working.
    I have a commercial version and not fully tested yet but I would not expect miracles on 40 or 80 (with extension).
    Surely it does tune and possibly receives pretty well, but taking into account loop size and loop thickness the transmitting performance will be quite bad
    If already topped at 20 to 25W PEP you will get probably 2-5W equivalent radiating on 80m comparing to the dipole.
    But it shall work well on higher bands 15-12-10 -I had good experience on 10m with FT817ND so 5W out.
    The only issue is the propagation getting worse on these bands recently.

    You can still experiment with longer loop and thicker one using copper or aluminium tubing with higher diameter - performance will increase on lower bands.
    But capacitor will have some limits both for power/voltage and frequency range coverage.
    For QRP shall be still fine.

    73 Thomas
     
    N1PRH, OH8STN, AD5KO and 1 other person like this.
  7. KI6TRA

    KI6TRA Ham Member QRZ Page

    A dipole will almost always be more efficient than a magnetic loop...but you need to be able to deploy it first. I wonder how many QSO's people can do with a 40M dipole deployed in their living room:



    That was from a customer few months ago:

    "Just for fun… F-loop (standard) from Aug 28. Indoors. 5 watts. I’m a newly upgraded HAM to hf and really enjoying it. Your antennas are good stuff! Cheers, Mark"

    [​IMG]

    A more powerful magnetic loop will be released in few weeks from now:

    http://us3.campaign-archive1.com/?u=e1cdcbe4da58e8277f75bd6b9&id=cdf412e790&e=[UNIQID]

    Carl
     
    N4GST, OH8STN and K0PIR like this.
  8. KF5FEI

    KF5FEI Ham Member QRZ Page

    FYI for those wanting to build their own QRP mag loop -- Midnight Science and several other vendors sell the dual-section 365 pF caps and the reduction drives. Typical price is $20-22 for the cap, $11 or so for the reduction drive, and $3 or so for the reduction drive bracket.
     
    K3RW, N4GST, K2MOB and 2 others like this.
  9. F4HPX

    F4HPX XML Subscriber QRZ Page

    Agreed
    not much space in living room for a dipole
    In US homes are often made from wood so you can use it possibly inside.
    I tried it in Lisbon in 20 something storey hotel - concrete and steel
    Did not work for me even close to the window. Ended by putting 30 feet of thin wire outside on small fishing rod because I could slightly open the window. The staff did not see that despite the hotel was lit entirely from outside...

    What can stop us to make a QSO done!
     
    OH8STN likes this.
  10. K2EIR

    K2EIR Ham Member QRZ Page

    OH8STN, Thank you for posting publicly accessible videos. I've seen a number of your loop videos and find them interesting. I was glad to watch them. I encourage you to keep up the good work!

    Attention K5TED:

    Anyone who has to order parts these days knows that it often means going to multiple vendors each with its own shipping charge, typically $9 per order stateside. A capacitor such as shown may cost $20 to $25 and the knob, vernier, and mounting plate $20 or more. ( sub total so far $45 + $18 shipping). While LMR 400 can be had for $0.65 per foot, sometimes you can't buy limited lengths alone. A 12 foot or 16 foot prepared jumper may have connectors on it and will be in the $20 range. ( Add $20 + $9). Oh, and don't PL-259 and SO-239's sell for about $5 - $7 each depending on quality? Didn't I see 5 of them? So one approaches $99 very quickly.

    ****

    Although loops may be less efficient than a dipole, the radiation pattern may be more favorable for distance, especially if the antenna must be height limited to just a few feet above ground, and that is why many choose to employ them. They also may yield noise reduction on receive.
     
    W6TUS, K3RW and OH8STN like this.
  11. KK5JY

    KK5JY Ham Member QRZ Page

    On the one hand, I'm very happy to see so many people experimenting with magnetic loops. This is the future for a lot of hams, keeping them on HF, or getting them on HF from limited spaces. And $99 for a starter antenna isn't too outrageous. My first HF antenna was a $99 MFJ "apartment antenna," and after making something like $99 worth of upgrades to it, I had finally learned to just build my own antennas. ;)

    On the other hand, I remember the first time I saw an AlexLoop for sale in the US. It proved to me that I was in totally the wrong business, because I could build two or three QRO loops for the same frequency range, for the same price as a single QRP AlexLoop. Again, I'm glad these kits are around as starter antennas for folks who want to tinker with magloops, but they are a little overpriced (or in the case of the AL, a lot overpriced) for something that is so easy to outgrow.

    The best antenna supply retailer I have found to date is Lowe's [lowes.com]. I still remember the first time I went to Lowe's for something that was actually a home-improvement item, and it was so strange to get such things from a ham store... ;)
     
    OH8STN and AD5KO like this.
  12. AD5KO

    AD5KO Ham Member QRZ Page

    That's where I go. :)

    They talk about these loops like it's a new idea but they have been around since before WW1. It's just that newer hams don't know about them. You can tune just about anything with a good sized capacitor.. wire fence, iron bath tub, flag pole, etc. It's not magic.
     
  13. KK5JY

    KK5JY Ham Member QRZ Page

    I think that's a lot of it. Proper construction requires more care than a dipole, so most antenna books don't treat the magloop as a starter antenna. Wire antennas dominate the literature.

    I also see a lot of senior ham "experts" around the web who talk trash about magloops, as if it is impossible for a magloop to perform well. One Aussie ham in particular emailed me about one of my antennas, asking questions that made me realize that he hadn't even read my web article, because most of his questions were answered in the article. Then, he wrote his own article, reviewing my antenna, and after making numerous false and/or unsubstantiated assumptions about how all the extra losses that he knew my antenna had that I hadn't thought of, he pronounced my antenna to be a poor design. He did this to other people, too. I have done the models, so I know how it performs, but he went out of his way to make up bogus loss figures on an antenna he had never seen, because he was apparently on a quasi-religious quest to denounce magloops as poor antenna designs.

    People who do that kind of thing float around QRZ from time to time, and their "help" isn't "helpful" to the practice of magloop-building, either.
     
  14. AD5KO

    AD5KO Ham Member QRZ Page

    Well, I didn't say it didn't work, I just said it wasn't worth $99.00 :rolleyes:

    Now, I'm old and I'm going to bed. :D

    73.
     
  15. KK5JY

    KK5JY Ham Member QRZ Page

    My comments were "present company excepted," of course. ;)

    Yeah, I'm hoping for nice enough weather tomorrow to put up my most recent 20m QRO loop. :cool:
     

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