WA3WSJ: Bead-Wire Antenna
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Hello all, I received lots of emails concerning my "Bead-Wire Antenna." I've decided to post on the reflectors rather than send out to each Individual op. Here's what I did to make my antenna. I went out to my local craft store called " The Rag Shop" and bought a 40' spool of flexible bead wire. This stuff is very strong, has a clear tough plastic coating over it, but won't take solder. My wire has seven strands to it. It comes on a plastic spool that's about 2.75" in diameter and 5/8" thick. It even has a clear plastic cover that snaps over half the spool to keep the wire etc on the spool. The wire measures .012" in diameter so it's very small and light. In fact my 40' of wire and 40' fishing line with spool weighs-in at less than 1oz! I tie one end of the bead wire to 40' of 30lb test fishing line. On the on the fishing line I tie a loop. I tie about an 1" loop on the end of the fishing line so I can attach a 1oz lead sinker. The sinker is one that is egg shaped and has a wire loop at the top. In the field I simlpy slip the fishing line loop through the wire loop and double back over the sinker. This makes for a solid tie that can be taken off easily anytime. This sinker makes it easy to throw up the bead wire into a tree too. At present I use three ground radials each 16' in length made from #26 black stealh wire. I plan to make my ground radials out of the bead-wire too to save on space and weight. I tried this setup yesterday in my back yard with my KX1. On 30m I had 4.0W out with a 1.0:1 swr. On 20m I have 3.8w out with a swr of 1.2:1 and on 40m I have 2.8w out with a swr of 1.1:1. My entire trail radio package weighs-in at 1.6lb. Here's what I use on the AT: Radio: KX1 with 30m option Battery: Powerizer 11.1V 1800mah 3-cell Lithium Polymer ~4.5oz Antenna: Bead-Wire Ant. Attached with 2-post to bnc adapter Paddle: AT Paddle Mini (plugs directly into KX1, 3.5mm stero plug) The entire package stores in a small camera case! p.s. You can buy silver coated bead wire to solder to, but it's expensive! 72, Ed,WA3WSJ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Ed,
Some of this stuff is plastic coated steel or stainless steel, similar to a fishing leader. This could explain the difficulty in soldering to it. If it's truly not copper based, I would be concerned about potential resistive losses for long antenna runs. Is there a way to determine what material this wire is made from? Steve aa8af > -----Original Message----- > > I received lots of emails concerning my "Bead-Wire Antenna." > I've decided to post on the reflectors rather than send out > to each Individual op. > > Here's what I did to make my antenna. I went out to my local > craft store called " The Rag Shop" and bought a 40' spool of > flexible bead wire. > This stuff is very strong, has a clear tough plastic coating > over it, but won't take solder. My wire has seven strands to > it. It comes on a plastic spool that's about 2.75" in _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: WA3WSJ: Bead-Wire Antenna
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Since RF current flows only along the very surface of the conductor, the
silver plated stuff ought to be very good even if a bit expensive! Ron AC7AC -----Original Message----- Ed, Some of this stuff is plastic coated steel or stainless steel, similar to a fishing leader. This could explain the difficulty in soldering to it. If it's truly not copper based, I would be concerned about potential resistive losses for long antenna runs. Is there a way to determine what material this wire is made from? Steve aa8af > -----Original Message----- > > I received lots of emails concerning my "Bead-Wire Antenna." I've > decided to post on the reflectors rather than send out to each > Individual op. > > Here's what I did to make my antenna. I went out to my local > craft store called " The Rag Shop" and bought a 40' spool of > flexible bead wire. > This stuff is very strong, has a clear tough plastic coating > over it, but won't take solder. My wire has seven strands to > it. It comes on a plastic spool that's about 2.75" in _ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Steve-292
Since the wire is quite thin, the resonant element which results will
have a rather high-Q and therefore best used for a narrow range (such as the CW sub-band). My wife does beading and uses the stuff; it looks to me like stranded stainless wire with a nylon jacket. My guess is that the high Q will win out over the skin effect of the SS. Furthermore, although nylon is lossy at RF, that usually applies where the tangential electric field is relatively intense, such as when the nylon serves as an insulator or a capacitor dielectric, rather than merely as a jacket. I also think Ed will have loads of fun in spite of the losses. :) Stay dry, man! Marshall, WA3VPZ Steve wrote: > Ed, > Some of this stuff is plastic coated steel or stainless steel, similar > to a > fishing leader. This could explain the difficulty in soldering to it. > > If it's truly not copper based, I would be concerned about potential > resistive losses for long antenna runs. > > Is there a way to determine what material this wire is made from? > > Steve > aa8af > > > -----Original Message----- > > > > I received lots of emails concerning my "Bead-Wire Antenna." > > I've decided to post on the reflectors rather than send out > > to each Individual op. > > > > Here's what I did to make my antenna. I went out to my local > > craft store called " The Rag Shop" and bought a 40' spool of > > flexible bead wire. > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: WA3WSJ: Bead-Wire Antenna
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Doing the math, a wire self-resonant at 7 MHz exhibits 2:1 SWR limits that
vary with the wire size as follows: #8 wire = 280 kHz #12 wire = 270 kHz #30 wire = 160 kHz Since the antenna is probably less than self-resonant length (1/2 wave or 1/4 wave over a perfect ground) the bandwidths will be greater than that owing to the matching network or ground losses. However, these numbers provide some idea of how the size of the wire affects bandwidth. The original poster was using a KX1. He didn't say, but I'd assume he's using an ATU, perhaps the KXAT1 built into the KX1. Ron AC7AC -----Original Message----- Since the wire is quite thin, the resonant element which results will have a rather high-Q and therefore best used for a narrow range (such as the CW sub-band). My wife does beading and uses the stuff; it looks to me like stranded stainless wire with a nylon jacket. My guess is that the high Q will win out over the skin effect of the SS. Furthermore, although nylon is lossy at RF, that usually applies where the tangential electric field is relatively intense, such as when the nylon serves as an insulator or a capacitor dielectric, rather than merely as a jacket. I also think Ed will have loads of fun in spite of the losses. :) Stay dry, man! Marshall, WA3VPZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: [QRP-L] WA3WSJ: Bead-Wire Antenna
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In reply to this post by WA3WSJ
Hi Ed,
I find your SWR readings a bit contradictory to my antenna modeling in EZNEC. Modeling 4 radials 17.28' each and a radiator of the same length with the radials 7' off the ground and the ends and the feed point and feed end of the radials at 10 feet I get a SWR of about 1.6 to 1. If I change the radiator to a 40' length and feed it the exact same way and heights I get a feed impedance of 325 ohms and a reactance of -1147 Ohms for 14.06 MHz. which isn't what I would call acceptable. For 7.04 MHz I get it near perfect with SWR of 1.19 to 1, at 59.5 Ohms and -1.169 Ohms reactance. Very Nice. 30 meters comes out at 10.12 MHz with 283 Ohms and +828.7 Ohms reactance. SWR of 54.2 to 1. Not very nice. So, unless you are running a tuner and that was the best your tuner would adapt the antenna to your rig, then I can see where you got your numbers. Either way, the antenna on any band except 40 meters is not going to radiate very well UNLESS you install the tuner AT THE FEED POINT of the antenna so the COAX is not contributing to the losses in the system. Even then I would recommend looking at the radiation pattern and angle of attack for that antenna and see it is what you wanted. A 20 meter ground plane antenna as I first described has a very nice single lobe pattern with an angle of attack of 20 degrees and a very acceptable SWR. On 40 meters with the 40' radiator it runs 22 Degrees angle of attack so again, a nice antenna with a very nice SWR. Make the entire antenna as a 40 meter ground plane (double the 20 meter wire lengths with same height above ground) and you get 1.12 SWR will NIL for reactance and the same attack angle of 22 degrees. Very close to your 40 foot radiator model. So, how did you get your SWR readings? Tuner or No Tuner? And located where? Best 73 72 Michael Baker K7DD [hidden email] -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Edward R. Breneiser Sent: Friday, October 06, 2006 7:55 AM To: [hidden email]; [hidden email]; [hidden email] Cc: [hidden email] Subject: [QRP-L] WA3WSJ: Bead-Wire Antenna Hello all, I received lots of emails concerning my "Bead-Wire Antenna." I've decided to post on the reflectors rather than send out to each Individual op. Here's what I did to make my antenna. I went out to my local craft store called " The Rag Shop" and bought a 40' spool of flexible bead wire. This stuff is very strong, has a clear tough plastic coating over it, but won't take solder. My wire has seven strands to it. It comes on a plastic spool that's about 2.75" in diameter and 5/8" thick. It even has a clear plastic cover that snaps over half the spool to keep the wire etc on the spool. The wire measures .012" in diameter so it's very small and light. In fact my 40' of wire and 40' fishing line with spool weighs-in at less than 1oz! I tie one end of the bead wire to 40' of 30lb test fishing line. On the on the fishing line I tie a loop. I tie about an 1" loop on the end of the fishing line so I can attach a 1oz lead sinker. The sinker is one that is egg shaped and has a wire loop at the top. In the field I simlpy slip the fishing line loop through the wire loop and double back over the sinker. This makes for a solid tie that can be taken off easily anytime. This sinker makes it easy to throw up the bead wire into a tree too. At present I use three ground radials each 16' in length made from #26 black stealh wire. I plan to make my ground radials out of the bead-wire too to save on space and weight. I tried this setup yesterday in my back yard with my KX1. On 30m I had 4.0W out with a 1.0:1 swr. On 20m I have 3.8w out with a swr of 1.2:1 and on 40m I have 2.8w out with a swr of 1.1:1. My entire trail radio package weighs-in at 1.6lb. Here's what I use on the AT: Radio: KX1 with 30m option Battery: Powerizer 11.1V 1800mah 3-cell Lithium Polymer ~4.5oz Antenna: Bead-Wire Ant. Attached with 2-post to bnc adapter Paddle: AT Paddle Mini (plugs directly into KX1, 3.5mm stero plug) The entire package stores in a small camera case! p.s. You can buy silver coated bead wire to solder to, but it's expensive! 72, Ed,WA3WSJ ______________________________________________________________ QRP-L mailing list Home: http://mailman.qth.net/mailman/listinfo/qrp-l Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.407 / Virus Database: 268.13.0/465 - Release Date: 10/6/2006 ______________________________________________________________ QRP-L mailing list Home: http://mailman.qth.net/mailman/listinfo/qrp-l Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] |
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