Rick, wow what a useful and appreciated response. A quick question = how
well do the so-called "inverted WYE" wire verticals perform? I don't have
nearly enough room in my tiny yard even for 16 or 32 buried radials. In
fact, I will probably have to extend the counterpoise wires at the time of
operation. We live in a rental flat, though luckily on the ground floor.
PS You may have already answered the question, but I have to open mail in a
cell phone (g). Tough for me to read with my shaky Parkinson's hands and
arms.
Thanks and 73,
--Doc/K0EVZ
On Nov 5, 2016 5:25 PM, "rick@dj0ip.de" <Rick@dj0ip.de> wrote:
> Doc, I forgot one VERY important point: DO NOT USE CARBON-FIBER POLES for
> vertical antennas. Running a wire snug against them results in a
> significant amount of loss, often as much as 10dB.
>
> Therefore always use pure fiberglass poles for vertical antennas.
>
> That point does not apply when you are using the pole the hang a horizontal
> dipole from.
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt, Germany)
>
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
> rick@dj0ip.de
> Sent: Sunday, November 06, 2016 12:22 AM
> To: 'Discussion of Ten-Tec Equipment'
> Subject: Re: [TenTec] Fiberglass poles?
>
> Doc,
>
> You will find a good selection of plans for wire verticals on my web site.
> http://www.dj0ip.de/vertical-antennas/
>
> All of these antennas have been built and used by one or more of the
> Spiderbeam team members.
> They are all field proven and many DX-peditions use them. I know that for
> a
> fact because I sponsor them and they send me pictures.
>
> These are quick and easy antennas to build. Of course the purest might
> want
> to optimize the feedpoint impedance to get a lower indication the SWR
> bridge, but that doesn't bring anything in performance. Performance is a
> function of two factors: 1) the height of the vertical radiator (radiation
> resistance) and 2) the efficiency of the ground network (radials) under
> it.
> Many of these antennas have an SWR of 2:1 or higher and they work just fine
> like that.
>
> A couple of rules to remember when working with fiberglass poles:
>
> 1) NEVER drill holes in a thin wall telescoping fiberglass pole; that's
> the best way to break them.
>
> 2) Best practice is to mount the retracted pole securely to something
> (i.e., long wooden ground stake), attach the wire to the top segment of the
> pole, and then push (telescope) the segments up, one after another. If you
> mount everything to the fully extended pole when it is laying on the
> ground,
> then try to pivot it up, it may break.
>
> 3) Guy lines should be thin rope and kept light (2mm Kevlar is perfect);
> they should always have a little slack in them, not be pulled tight.
>
> 4) Spiral the wire around the pole on its way to the ground, with about
> one
> turn every 2 to 3 ft. This reduces flopping in the wind.
>
> 5) When pressed tightly against the pole, it tends to reduce the velocity
> factor of the wire by about 0.01. Example, if the vf of the wire is
> normally 0.98, then it will be about 0.97 when snug against the pole. So
> your radiator will be a little shorter. Regardless, start with full size
> and trim to resonance.
>
> 6) A quarter wavelength 80m vertical, 67' long, fits easily onto the 60'
> Spiderbeam pole, due to the reduced vf and the spiraling of the wire.
> Start
> with the normal full length of wire (according to the formula) then as you
> approach the bottom of the pole, wind the wire a bit closer together (2
> turns per ft. for the bottom 5 ft.). The antenna will be resonant too low.
> Unwind a little wire, space the turns a little farther and trim off a
> little
> to raise resonance.
>
> 7) Though traditionally we have used 1/4 wavelength radials, they may be
> shorter (as short as 1/8 wavelength) and though it is better to have them
> all the same length, that is not absolutely necessary. 24x 1/8 wavelength
> radials will give you better performance than 12x 1/4 wavelength radials
> and
> uses the same amount of wire.
>
> 8) If you use elevated radials, you will find it works "OK" with just one
> radial, better with two, a little better with 3 but more than 4 doesn't buy
> much more gain. Each elevated radial is usually as good as 6 ground
> mounted
> radials (YMMV). However these radials must all be the exact same length
> and
> resonant 1/4 wavelength long.
>
> Rumor has it that with each fiberglass pole, Scott is throwing in a bag of
> sunspots... though I haven't confirmed this.
> Check here: http://www.spiderbeam.us/index.php?cat=c2
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt, Germany)
>
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Doc
> Sent: Saturday, November 05, 2016 9:27 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Fiberglass poles?
>
> Barry, thanks a lot for this feedback re Spiderbeam. I have had some
> questions about the cost, which seem too low for such length.
>
> PS Could you send me the formula for making up some wire verticals?
>
> 73,
> Doc/K0EVZ
>
> On Nov 5, 2016 1:46 PM, "Barry N1EU" <barry.n1eu@gmail.com> wrote:
>
> > The Spiderbeam poles are also worth considering. Our good friends
> > W4PA and DJ0IP are intimately involved.
> >
> > 73, Barry N1EU
> >
> > On Sat, Nov 5, 2016 at 3:20 PM, Doc <k0evzdoc@gmail.com> wrote:
> >
> > > What has been your experience with the MFJ or Jackite collapsible
> > > fibreglass poles, either 33' or 43' in length? I have been
> > > considering a purchase in order to construct a wire vertical.
> > >
> > > Would really appreciate hearing from you, please.
> > >
> > > GL in the SS!
> > >
> > > 73,
> > > --Doc/K0EVZ
> > > _______________________________________________
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