BPNJ,

When back and checked the eBay Auction Listing.

The main Photo/Image shows Two (2) 'separate' "Individual" Ferrite
Rod Loop Antenna Heads (VLF & AM/MW) with one Base Unit.

AFAIK - The Coil is the Coil and for the same 'type' Ferrite Material
and Cross Sectional Area: The Coil will not vary too much in its size
and length for the same band of frequencies.
? Comments Please . . .

Most Ferrite Rod Antenna Coils that I have seen for AM/MW are Single
(One) Layer Wrapped: Most likely because for the at home builder
'doing-it-by-hand' this is the easiest method.
? Comments Please . . .

However - I have seen Coils that a
- Evenly "Spaced" over the 'full length' of the Ferrite Rod
- Single Coil = One Coil near one end of the Ferrite Rod
- Twin Coils = One Coil near each end of the Ferrite Rod
? Comments Please . . .

For the same 'type' Ferrite Material and Cross Sectional Area as the
Ferrite Rod gets Longer and Shorter the amount of RF EMF Energy
{Signal} gathering Increases or Decreases respectively.
? Comments Please . . .

The Ferrite Rod is used to gather and concentrate the RF EMF Energy
{Signal} and reduce the physical size of the Antenna Element for
an effective smaller antenna.
? Comments Please . . .

It is my understanding that for a given 'type' Ferrite Material with
a given Cross Sectional Area the Ferrite Rod can only be so long
before the Gains are overcome by the minuses of using a longer
Ferrite Rod. At some point as the Ferrite Rod gets longer; then
the Cross Sectional Area has to Increase too. The result is a
Longer and Thicker Ferrite Rod and these are Costly Items that
usually do not warrant the cost based on any potential or actual
improvement Signal Handling.
? Comments Please . . .

iane ~ RHF
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