On Nov 27, 5:31 am, "Richard Fry" wrote:
"John Smith" wrote I don't believe any of the modeling programs are "aware" of what dynamics
are causing the DLM to outperform expected/modeled results--

__________

Using Vincent's own numbers for the performance of a 3.5 MHz standard DLM
shows otherwise, and that doesn't necessarily take a modeling program to
discover.

As I stated in my last post in this thread, I was NOT using NEC to model the
DLM in any form. I modeled a standard, base loaded monopole of the same
physical height as the 3.5 MHz DLM, and compared the NEC result for that to
the DLM data in the URI test report, and the DLM data to the well-known
performance of a standard 1/4-wave monopole -- which performance has been
accurately measured.by broadcast stations thousands of times over the last
70+ years.

That DLM system radiated only about 59% of the power applied to it, which is
well below the ~95% radiated by a standard 1/4-wave monopole using a
"broadcast type" buried radial ground.

Check the numbers for yourself.

RF

It doesn't matter. He mounted one on his bike, and he can
make contacts, so all the rules go out the window... :/
What I'd still like to see is the reinvention compared against
a same height short monopole which is purely top hat loaded.
I bet the DLM reinvention loses a bit of it's gee whiz status...
If the DLM is all it's cracked up to be, the LW aircraft beacon
boys should all be switching over real soon..
I'm not going to hold my breath waiting..
Using extended helical windings for short whips is nothing new
either.
The CB'ers have been doing it for years and years.
It's a valid concept which in *some* cases can give an
advantage, but it sure isn't anything new.
People whine that no one tries the DLM in the real world.
But I already tried my own versions of basically the same thing
many years ago. "for mobile use"
But I don't use any versions of that basic design any more because
it is proven inferior vs other more standard methods such as
top hat loading, or using a single large high Q loading coil
instead of a bunch of split narrow wound coils of lower Q and
higher overall loss.
I still stand by my previous statements that the DLM is not an
optimum design for a short vertical. It has various warts, which
I won't bother elaborating on.. There is not much point since it
will just fly off into space ignored by the usual DLM-Gaussian
campers.
MK