On 30 ago, 02:53, VK3XL wrote:
Wimpie;590418 Wrote:


[removed]
My intention is to use this antenna on the 10 meter FM section of the
band. I have been given a 1/2 wave "Ringo" antenna that is missing the
ring. I intend to convert it to the "stationmaster" type antenna as I
think it will be easier to get the matching system right using a coil
spaced from the bottom of the radiator than try to make a new matching
ring etc. Thus if I could locate plans for the making of such an
antenna it would save me a fair amount of time in the calculations and
cut and try type of antenna building.

The info collected so far is at least a starting point for the
conversion of this antenna.

Thanks to all who have given input, it is greatly appreciated.

Mike
VK3XL

--
VK3XL

Hello Mike,

In your case, I would try to rebuild the ringo. The construction is
not that difficult and the capacitance between the radiator and
support is designed to provide the right capacitance for doing the
matching. To get your whip to resonate as a half wave, you need that
capacitance for making the step from 50 Ohms to about 1500 Ohms (also
when using the series coil solution). Instead of aluminum strip, you
can use heavy copper wire.

The ringo gives you the freedom to change the inductance (smaller/
shorter ringo) and the tap. Because of the DC short it gives some
protection against the high energetic LF components in nearby
lightning strikes. Disadvantage is the somewhat less useful
bandwidth.

http://www.ea8zq.com/ant27.htm gives some info, the text is Spanish,
but the images are nice.

http://www.elettronia.it/Catalogo-d.asp?cod=A052 shows a picture of a
ringo antenna (Italian site). The ringo has about 2 turns.

Somebody living close to me had also a ringo antenna (with about 2
turns). The antenna could be tuned at the antenna base by extending a
tube downwards. I'm sorry I don't have picture.

Best regards,

Wim
PA3DJS
www.tetech.nl