K0GKJ – Just Another Ham
The New QTH – A Floating Shack

Quarter Wire to Copper Tube Slim-Jim

Well, after the hex beam came down (being shipped to the next proud owner – in Missouri), I was left antenna-less, so until the feedline conduit comes down, I experimented with a “quarter wire” (quarter wavelength ground plane vertical whose magnet mount I stuck to the top of a steel air conditioner compressor:

Made a few contacts in Punta Gorda (ten miles or so away), but weak and noisy. So I had homebrewed a slim jim copper tube antenna whose design is supposed to sport some gain (not a ground plane like the wire, but rather a tuned stub that I tuned to minimum SWR with my antenna analyzer).

Tied the SJ to my old HF feedline instead of the quarter wire, and now am talking to folks 30 miles away simplex (no repeaters). Huzzah!

Still playin’ around, but seems to be a good design with lower noise and longer range on these (line-of-sight) frequencies.

No good, obviously, for anything longer range than that, but one step at a time, as they say. Not bad for an antenna that’s only a few inches wide and just a tad over four feet long.  

 

I continue to investigate equipment that will allow me to relocate my primary QTH to my boat – things like backstay insulators (allows me to convert one of the wires that holds up the forty-two foot mast – 54 feet AGL) into a long-wire antenna), copper foil (which connects the antenna to the tuner to the grounding shoe on the hull, i.e., the RF ground), lengths of 450Ω twin lead that will serve to enhance my counterpoise to better launch signals, big honkin’ fused power leads to the batteries, etc. Then, of course, installing all this stuff is tricky and time-consuming so as to avoid nasty RFI on the marine electronics (unacceptable when this stuff helps navigate the ship to avoid hostile waters, grounding, sinking, and all that undesirable stuff)!

Watch this space…

73 de Gene K0GKJ dit dit

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3 Responses to “Quarter Wire to Copper Tube Slim-Jim”

  1. Hi,

    I’m a big fan of the slim jim, I have a 300 ohm ribbon feeder one at my QTH, current DX record is 90 miles SSB with 30w!

    73

    De Matt 2E0FNG

  2. yup, in an earlier post on this same blog, I documented my construction of the plan for this antenna located at http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=12033. 73 Gene


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