On 25 Oct, 08:22, Cecil Moore wrote:
art wrote:
Gentlemen
In constructing "slow wave" antennas for top band I am finding that a
wavelength in equilibrium is a bit longer than expected.
As I am using large diameter formers for circular radiation I suspect
the reduction in number of turns is the reason.
Does anybody know of a turns versus length graph has been made for
this phenomina and where I could find it?
At present I start with scaling up a Tesla coil as a starting point
but that is becomming somewhat laborious after winding a few antennas.
( I will be placing a photo of my antenna on my page in a few days)

Here you go, Art. Equation 32 and Fig. 1 should be within
10% of what you need assuming your device meets the test
equation boundaries given between Equation 31 and Equation 32.

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf
--
73, Cecil http://www.w5dxp.com

Thanks so much for that article by the most formost
scientists on this subject.
I have not made things easier on myself lately as I
have migrated to tinned
copper braid for extra gain which obviously increases
the slow wave length somewhat because of the added
indunctance which some would considered as being cancelled Hi.
At first I was considering the actual wire length
in the braiding b ut that influence became little
compared to the current pertabutations. Also have
found that the standing waves do not completely
disapear until the top band radiator is up at a
one wave height which was a bit of a dissapointment
but still acceptable at 850 feet.
Thanks again for what appears to be a jewel
Art Unwin KB9MZ....XG....(uk)
Can't wait to add a flyback transformer so I can
make a radio wave missile launcher.