[Elecraft] OT - SteppIR Vertical and Elecraft Products

[WILLIS COOKE]

David, whether a vertical is the best antenna or not depends on where you are and what you are trying to achieve.  Some things to consider are:
1. Verticals are generally more subject to man made noise than horizontal antennas.
2  When putting down radials the first radial is most important.  How many you need depends on your local conditions.  You will probably get about 50% as much good from your second radial as the first.  You will not get much after about 16, but you will get a little.  Think about parallel resistors because you are coupling to the ground.  The subject is very complicated and if you interview 100 vertical owners you will find that either what they have is the very minimum or that they need more, whether they have one or two hundred radials.  Putting the antenna in the middle of the ocean is the best, but few can manage that.
3.  The angle of radiation above the horizon depends mostly on the conductivity of the surface well beyond the radial area, not the number of radials.  You can't do much about the conductivity of the soil beyond your property, but it is important.
4.  If you want to contact stations that are farther than 10 miles away and less than 1,000 statute miles away you are better off with an inverted V at about 40 ft or so.  If you want stations beyond 2,000 miles away the vertical is usually best.
5.  The shorter the vertical, the lower the radiation resistance and the lower the efficiency, up to about 0.33 wavelength.
6.  Don't use a half wavelength at your desired frequency because it is very difficult to match an antenna with nearly infinite reactivity.  You can put a coil in series to make it about 0.75 wavelength so you can match it, but it will not be easy.
7.  The SteppIR BIG IR vertical has a tape that runs up a fiberglass tube so the vertical can be any length.  Usually 0.25 wavelength at your frequency of operation.  They work well, but they are not inexpensive and they require a control cable as well as a coax.  The same radial rules apply as for any other vertical.
8.  An antenna tuner at the base of a vertical is a good thing.  Weather proof antenna tuners are not common and usually only accommodate low power, 100 to 200 watts.  If you coax is fairly short and your SWR is not really high you usually can use the tuner in your transceiver in the house.

Selecting an antenna is great fun, but not easy.  Good Luck.

Willis 'Cookie' Cooke 
K5EWJ


--- On Sat, 5/16/09, David Wilburn <dave.wilburn at verizon.net> wrote:

> From: David Wilburn <dave.wilburn at verizon.net>
> Subject: [Elecraft] OT - SteppIR Vertical and Elecraft Products
> To: "Elecraft Discussion List" <elecraft at mailman.qth.net>
> Date: Saturday, May 16, 2009, 10:52 AM
> Recent discussion regarding verticals, internal antenna
> tuners and 
> remote antenna tuners was very interesting.  Based on that
> discussion, 
> it seemed the "optimized" solution was a
> vertical, with good radials, 
> and a remote tuner at the base (generalization).  Based on
> a quick 
> check of remote tuner cost, new they seemed to start around
> $400 and 
> go up from there.  I have not looked at used cost.  I have
> been burned 
> too many times on eBay.
> 
> Some have used cheaper tuners and put them in a waterproof
> bin.  A 
> worth while option to consider.
> 
> I would like to try a vertical here, and possibly a setup
> for when I 
> travel.  Being on the east coast, it is not hard to get
> near salt 
> water for major contests.  I only have basic wire antennas,
> no beams, 
> no quads, and no tower.
> 
> In the near term I want to try out (experiment with) a
> 33' vertical. 
> At Frostfest this year I picked up 32' or so of
> fiberglass mast.  I am 
> going to tape a wire to this that is 34' long, twist
> the mast to wrap 
> the slack up, much like a widely spaced helical.
> 
> When setup at home, it would (eventually) have a good
> ground field 
> (would start out with 16 radials and work my way up to
> 60'ish). The 
> coax run when used at the house would be less than 40'.
> 
> When setup for portable operation (connected to mount I
> have for my 
> trailer hitch, to use when parked) it would have 4 radials
> of a length 
> not yet determined and the coax run would be less than
> 20'.
> 
> In both cases I would be using the tuner for the K2
> (portable) or K3 
> (at home).
> 
> In the long term, I am thinking about the SteppIR vertical
> (haven't 
> decided which one).  Same deal with the radials.  It would
> inherit 
> what I had down, or start at 16 and work up.
> http://www.steppir.com/files/vertical%20brochure.pdf
> 
> Current plans are for ground mounting.  I understand that
> as radials 
> go, more is better. The radials would be black insulated
> wire on, or 
> within 1" of the surface of the ground. They would not
> be cut to 33' 
> or less if the space was not available.
> 
> I am curious on the experience of the group with a similar
> vertical, 
> tuner at the rig, and short coax run.
> 
> I am also curious of the experience of the group with the
> SteppIR 
> verticals.  There is similar up front cost as the vertical
> / remote 
> tuner solution (assuming a new weather proof tuner).
> 
> Thanks for the always enlightening discussions.  73
> 
> Dave Wilburn
> NM4M
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