Thanks very much for showing me HYpower Anntennas. They look very interesting, and I am going to call them with questions. Gerry
Sent from my iPhone this time > On Jun 26, 2014, at 9:39 AM, Walter Underwood <[email protected]> wrote: > > For pre-built antennas, HyPower is a good choice. He has lots of options, fan > dipoles, loaded dipoles, even combinations. I have a fan dipole made from a > full-size 40m element and an element that is full-size for 80 and loaded for > 80. He also sells the loading coils if you would rather DIY. > > http://www.hypowerantenna.com/ > > wunder > K6WRU > >> On Jun 26, 2014, at 5:30 AM, "Charlie T, K3ICH" <[email protected]> wrote: >> >> Don't rule out traps. >> >> Also, the RF Connection and probably others, sell a nice stranded copperweld >> wire that has a black polyethylene insulation. If I remember correctly, it >> is 13 ga and is ideal for antennas. For all practical purposes, it doesn't >> stretch, is fairly slippery and only a little "springier" than hard drawn >> copper. >> >> I use those double ferrule aluminum crimp on's that are designed for >> flexible wire cable to hold everything together. I was concerned about them >> holding through the poly insulation, but the following antenna has been up >> for about ten years now. It consists of a double (fan) dipole with a pair >> of 80 meter traps in the top leg for 160 & 80 M coverage and a pair of 40 >> meter traps in the lower leg for 60 & 40 M coverage. It is fed thru a 1:1 >> balun with RG-213 and is tuned for resonance. Basically, I operate SSB 99% >> of the time, so the antenna is tuned for that end of the bands. An MN-2700 >> tuner in the shack takes care of small excursions from resonance. It's >> only up about 50 feet, so performance is what you'd expect. It's not >> straight either and is sort of a lazy Z, being strung between two 55' >> telephone poles that are 105 feet apart. The ends droop down at about 45 >> degrees to tie-off points in trees. A compromise? Yes, but it works. >> >> 73, Charlie k3ICH >> >> >> >> >> ----- Original Message ----- From: "Jim Brown" <[email protected]> >> To: <[email protected]> >> Sent: Thursday, June 26, 2014 1:55 AM >> Subject: Re: [Elecraft] RF in the Trees >> >> >>>> On 6/25/2014 5:43 PM, Dauer, Edward wrote: >>>> So, I've been selecting two of the tallest >>>> candidates a couple of hundred feet apart and stringing a stout nylon rope >>>> between them. In the middle of the cord I attach the balun for the Vees, >>>> thereby allowing the legs to be in the clear, moveable from side to side, >>>> and tied to smaller (8') trees at their distal ends. In one variation on >>>> the theme I had a 40 meter dipole as the center section of the supporting >>>> rope, tied to the same balun as an 80 meter vee. In another I tried a >>>> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't >>>> perform as well as the full length version. >>> >>> If you can suspend a flat antenna between two tall trees, why would you >>> want an inverted vee, which is a less effective radiator? >>> >>> Your two trees 200 ft apart could support a full size 80/40 fan and a >>> 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good >>> antenna, and is easy to build. >>> >>> My technique has evolved to starting with #8 bare copper from the big box >>> store, stretch it VERY slowly between a tree and a trailer hitch until it >>> breaks. Do this carefully where there's no one around to get hurt. Now you >>> have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use >>> that for the longest dipole in each fan. Use #12 or #14 THHN (house wire) >>> for the other elements. I make spacers by cutting 1/2-in PVC conduit into >>> lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire >>> fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in >>> place by soldering short lengths of copper around the spacer to the bare >>> copper of the long element. >>> >>> The higher your antenna is, the more robust your center insulator should >>> be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50 >>> ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending on >>> the Z at resonance. Don't waste a dB or two with small coax. My 110 ft >>> 80/40 fans are fed with Belden 8213. >>> >>> For weights, I fill 6 gallon water jugs with dry sand, and tie one to one >>> end of each span. The other end can be fixed. I have pulleys high my trees. >>> If you don't have a pulley and weight, your antenna WILL end up on the >>> ground, and it won't take a big storm for that to happen. >>> >>> My HF antennas are all at the 110-120 ft level in a dense redwood forest >>> that towers 50-75 ft above them. They work. My "seat of the pants" >>> observation is that attenuation increases with frequency, and is greatest >>> with vertical polarization. 432 MHz is a waste of time, 2M sort of works, >>> and 6M works pretty well. >>> >>> For an analysis of the value of height, study this. It supports the >>> statement earlier in this thread that a high dipole beats a low tri-bander. >>> >>> http://k9yc.com/VertOrHorizontal-Slides.pdf >>> >>> When Fred observes that the ends of antennas are "hotter," he means that >>> this is voltage maxima and a current minima, so good insulation is needed >>> to whatever the antenna is attached. I once melted heavy dacron rope that >>> was tied directly to the end of said dipole (well, twice, actually). The >>> extra ingredient was that it was wet. Duh. >>> >>> 73, Jim K9YC >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [email protected] >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] > > -- > Walter Underwood > [email protected] > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
