[Lowfer] Ultimate LOWFER Transmitter?

[John Davis]

>
>Ha-ha.   Very funny :-)    A little early for April Fools isn't it Stewart
>my old mate ?    Or just back to your "energy creation out of thin air"
>tricks again ?
>


I'm sure Stewart is funnin' us a bit (as all of us Americans say...in the
Western movies:) but not in the way you think.  He is correct, if one key
assumption is true: namely, that all of the radiating antennas are equally
bad!

A better way to think about it is to split the power from one source into
multiple parts and apply each feed to a separate antenna.  If the losses
associated with each antenna are very high compared to the theoretical
ideal, and if the induction zones around each don't couple very tightly, the
efficiency of the whole system *is higher than* that of the individual
radiators, by a factor of 3 db for each doubling of the number of radiators.
This is the principle behind multiple tuned vertical radiator systems of the
type used at VLF stations such as SAQ, for example.

Thus, if you double the number of radiators and provide them *each* with the
full original power level (thus doubling the applied power, as well as
doubling the efficiency) --and the sources are coherent with each other, of
course-- you do achieve 3 db + 3 db = 6 db more output from the whole
system, rather than just 3 db more.

Note that this is only true if the efficiency is very bad to begin with!
Thus, it is increased antenna efficiency, not power from nowhere.  (Stewart
and Bill Cantrell and I had a long discussion about this a year or so ago,
and it finally soaked through to me what they were saying.)

What you are getting with each doubling of radiators is the same received
signal voltage as if you had four times the power going into ONE of the same
VERY BAD RADIATORS.  If you quadruple the sources, you might get 16 times
the apparent power as if applied to ONE VERY BAD RADIATOR.  And so on--up to
a point!

Depending how bad the radiators were at the start, at some point,
multiplying the radiating efficiency of the whole system is going to make it
start looking halfway respectable, and you will enter a point of diminishing
returns.  Doubling the number of sources then will then only slightly more
than double the radiated power; it will no longer quadruple it.

And, if the antenna efficiency were high enough in the first place (as with
a full-size radiator, or with an extraordinarily efficient system of short
antennas such as I seem to haveachieved with a multi-source MedFER I tried
some years ago) the whole concept falls apart.  Doubling the number of
sources working into closely spaced GOOD antennas only gives you double the
radiated power.

73,
John Davis