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SWL portable Antenna.

Discussion in 'Survival Communications' started by Tikka, Dec 18, 2011.

  1. Tikka

    Tikka Monkey+++

    As this is sold commercially I borrowed the idea and typically a Ham I modified it.

    The antenna is based on a retractable clothesline. The clothesline was replaced with #14 wire.

    Amazon.com: Kaito Radio antenna, T1: Electronics


    The red "alligator clip" to attach it to the radio's antenna. I added added a 3.5mm jack for radios which have a jack for external antennas. The jack requires having a male to male adapter with you. Typically the jack is better on receive than the red clip attached to the radio's antenna.

    As the wire can get tangled; choose a reel which can be taken apart easily. ;)
    Georgia_Boy likes this.
  2. ghrit

    ghrit Ambulatory anachronism Administrator Founding Member

    How long is the wire, and what bands can it transmit on? (I assume the xmitter has an antenna tuner in it.)
  3. Tikka

    Tikka Monkey+++

    For swl as much as you can fit on the reel. These reel antennas were sold or came with the radio by the Sony, Grundig and others. I said that is too simple to pay $15 + shipping. As I have SWL portables with and without an external antenna jack; I tweaked the design to do either.

    To transmit using reels you'd need two configured as a dipole. Or feed one in a similar fashion to an end-fed Zepp etc. In either case you'll need an antenna tuner and a ground.. As a good ground may not be easily available a dipole and a small tuner is preferred.

    This is a real nice SWL/QRP antenna; however it is overkill for SWL. ;)

    HF Reel Type Portable Antenna for QRP
  4. ghrit

    ghrit Ambulatory anachronism Administrator Founding Member

    Tx is what I was driving at, listening is whatever you can manage, if I remember all I think I remember. Thanks.

    (Wish I'd held on to the SWR meter I had back in the day.)
  5. BTPost

    BTPost Old Fart Snow Monkey Moderator

    Ghrit, Wire Length for SWL is a case of "More is Better"... Minimum would be 100 Ft, I would think. As Tikka says, an UNBALANCED Antenna requires an RF Ground. to work, correctly for Receiving OR Transmitting. For Receiving, this can be as easy as a coil of cooper tubing, buried in a 3 Ft Hole, that is refilled with Gravel/Sand and interspersed with some Salt. Then when you want the best reception, you go water the RF Ground. For SWL Listening, you don't even NEED to connect it, to the Radio, necessarily. What I teach, for the Alaskan Bush, is buy a 500Ft roll of Stranded #14 Copper Wire. Stretch out 300 Ft between the local Trees, and then coil 100 Ft in a 6 - 8" coil using TyWraps, and use the last 100 ft to connect to your RF Ground as designed above. Then you set your radio, near the coil, tune in a station, then rotate the coil, and radio, in relation to each other, for best signal strength. Really works well, and anyone can build it in an hour or so, after the hole is dug. This type of external antenna was well used out in the bush, until XM and Sirius SAT based Radios come online. Now, they dominate the Bush, and are good for everything, EXCEPT local News. .... YMMV....
    Tully Mars and dragonfly like this.
  6. DKR

    DKR Interesting ideas, interesting stories

    That is until the XM/Sirius go under (again) and your multihundred satradio becomes an expensive paperweight.
    BTPost likes this.
  7. Tikka

    Tikka Monkey+++

    Which one did you have?

    IMO, for rx or tx work a good match is important. I listen on SWL on frequencies which are way out of my antenna's resonant bands. The tuner makes it possible.

    This isn't mine but mine has pretty much the same things (two 24-240 6Kw and 30 mH roller inductor) inside:

    As BT said; for SWL it is a case of more is better.
    BTPost likes this.
  8. ghrit

    ghrit Ambulatory anachronism Administrator Founding Member

    20 years ago, I do NOT remember. Used it to tune quarter wave mobile whiskers (2 base loaded coils and a helical) and both half and 5/8 wave house mounted omni directionals on different houses. It had an rf power detector that I used to map the field on both vehicles. Had an inline power meter that I think robbed a whole lot of rf out of the radio, seemed like everything worked better with it out of the line.

    Both the house mounted antennas were Radio Shack. The mobiles were an el cheapo, a K40 and the Firestick. Had the SWR under 1.1 on all of them.
  9. Tikka

    Tikka Monkey+++

    As it had everything it sounds similar to what was called a "Port-a-lab" ?? Lossy or corroded circuits will do that; most electronics will list their insertion loss, etc.
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