[TowerTalk] Re: 80 Meter Hybrid Triangle Loop

[Guy Olinger, K2AV]

> * 2nd...I am on a city lot so an antenna with
> multiband versatility, within range of the rigs
> internal tuner is a consideration.

The art of the do-able. Articles, canned designs are fine, but do they 
match your possibilities. You can suspend wires in a model with fairy 
dust, not availble at Lowe's and banned by HOA rules, and leaving you 
in the lurch. Your remaining attack is messing with the designs in 
models to get a "tweaked version" that can be hung on supports you 
actually have.

> *  3rd...The configuration of this hybrid loop
> provided an easy feed point, laid out nicely in trees,
> and was vertical in nature. The feed point in the
> article allowed some vertical and horizontal
> polarization.

Common misconception, see Tom's comments. Getting it stamped out in 
favor of reality seems as impossible as killing all the roaches.

> Best of both worlds...which from your
> comments may be an impossibility.

> * 4th...At this point I do not know how to model
> antennas. This puts me at a disadvantage with regards
> to deseminating the information currently available.
> A good tutorial would help.

Not at all meaning to be dismissive, but how many books did you have 
to read before you got behind the wheel of a car. It's true it took 
you time to become experienced and worthy of passengers in the other 
seats. And for many the classroom time is prerequisite. But that's 
only because a car can be an unintended lethal weapon.

In modeling it's probably the best approach to just get one, and start 
driving. You don't have to worry about crashing or using up 
construction materials. If it doesn't work, just hit the bit bucket. 
Dig in the books as you go. Go post to Antennaware if you're having 
trouble with the fine points.

The antenna you are working on is a straightforward model. A good one 
to start with actually. It will show you what the currents are doing.

> * 5th...Gain with a loop at its fundamental frequency
> is basically equal to that of a dipole.

Only at the same height and orientation as the resultant transmitted 
wave from the "loop".

A vertical dipole is a poor performer by contrast with a horizontal 
unless you're over salt water or a copper-plated county. In ordinary 
circumstances the losses start with half your power dissipated in the 
ground and only get worse with clutter and proximity to the ground. 
City lot problems make "vertical" difficult to do well. Not 
impossible, but difficult.

Also if the loop is "irregular", meaning "sufficiently" different from 
a circle or square, the irregularities can squeeze out some of the 
possibilities, and make the basic loop/dipole comparison invalid.

> * 7th...Given the site, trees available, distance
> between endpoints, +/- 55' height, and location to
> house/shack, a vertical loop is do able.

All the more reason to get a modeling program and learn the currents 
and feeds. Your problem is an excellent starting point.

73, Guy.