On Wed, 19 Nov 2008 22:45:19 GMT, Rich Grise wrote:

But I've been searching the web for some weeks now, and I can't
seem to find any kind of formula, except there was this program
I downloaded - LPDA.EXE, which runs on DOS. Unfortunately, it's
in Russian or Polish or Uzbekistani - one of those East Yurp
languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif

Which I went through pretty much by-guess-and-by-gosh - can
anybody read that stuff?

Hi Rich,

Someone else has already provided the translation, so that will take
care of some of the wholes in data entry and reading.

There are a lot of factors I don't know about, like "Tau", and
all of the specific designs on the web are flat - something is
telling me I want one of those pyramid-shaped ones, but I really
don't know the difference (between that and flat) - it's probably
something to do with bandwidth or F/B ratio or whatever.

Tau is related to the shape of what you call the pyramid, or more
actually to the angle of the taper. This defines the smoothness of
matching across the span of frequencies you entered into the program.
As you can see, it also relates to the available gain. Another
correlative is it also relates to its length. All of these things are
trade-offs that lend to the rule of choosing what you want most and
giving up on the rest.

I note elsewhere that you wanted something about 1 foot long. There
is a Tau that will give you this boom length, and you got it on the
first guess.

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to
send myself to Log-Periodic School, where should I start?

You should start building what your screen shot gave you IF that is
the span of frequency you need (already questioned by other
correspondents).

73's
Richard Clark, KB7QHC