HFU HF Underground
Technical Topics => Equipment => Topic started by: Fansome on January 08, 2011, 0041 UTC
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Posted to rec.radio.shortwave:
Portable Wire Antenna [PWA] -by- Tom Sevart [N2UHC]http://www.reocities.com/n2uhc/portablewire.html
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Nice idea, much quicker and neater than wrapping insulated wire around a telescoping antenna.
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I think I first read about that trick in Joe Carr's receiving antenna book several years ago. Works well. I've used that trick with thin magnet wire indoors and outdoors. Wrap the wire around a hollow plastic tube just large enough to slip over the telescoping whip. Also works with ferrite toroids or even with those hollow core tubes used as RF chokes on computer cables - it's easier to overload with magnet wire wrapped around these than with plastic tubes, and takes fewer windings to accomplish the same purpose.
It's a little handier than the similar trick I heard about from Arnie Coro back in the 1990s about wrapping insulated wire around the whip - which also works pretty well as long as the insulated wire coil holds a set and doesn't need to be redone every time you want to use the expedient random wire antenna with your portable.
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I used to do the same trick with a 3-4 inch piece of drinking straw,(I recommend a Wendy's or Rally's straw,they're slightly bigger in diameter than most straws) and a length of insulated wire from a phone cord,enough to give you 18-20 turns on the straw and a 7-8 inch pigtail to hook to your longwire antenna w/ an alligator clip. You slide the straw up and down the antenna to find the "sweet spot" for best reception,ie; coupling w/ the internal ferrite antenna.
It does a nice job on radios that don't have an antenna jack or ones that do but overload w/ more than a few feet of wire.
To soup it up you can use the tuning capacitor from a junked radio between the straw's pigtail and the longwire. It acts like a combo antenna trimmer and frequency trap. When you've got it set up this way,you can move the whip away and back towards the radio for phasing,knocking out a lot of qrm and giving your longwire some directionality. When you're hearing what you want you peak it up w/ the capacitor for best listening.
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When on vacation I have a pocket Grundig with ssb I take a slinky along with me and hang it up in the window and clip my antenna lead to it and have had excellent results.
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Yeah, I use one of these when I'm on vacation with my G5. works nicely.
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Try the slinky with a random wire tuner inline,it really makes a difference from 160 meter band up to 10 meters. I use an old MFJ tuner I picked up at hamfest for princely five bucks. The thing is probably four inches by four inches and two inches deep.