Hello,

in the last weeks I have been fighting againts my two Tonna's crossed
Yagis: a 2x19 elements UHF and a 2x9 elements VHF.

I still cannot manage to have them up and running. Here are the
details of the story:

UHF
Both dipoles, when feeded separately, resonate perfectly between 420
and 426 MHz. Faston climps feed the diples (dont agree with this
solution but there must be a valid reason if they adopted them).
I have coupled them using two lamda/4 sections of RG-59. Each section
is 11.3 cm long... ### ((300/436) * 0.66) / 4 ###. They terminate on a
BNC wich goes on a Tee-BNC down to the RTX.
After the coupling the resonance is a little bit tighter, but still in
the range of 421-425 MHz. SWR for 436 MHz (the desired frequency), is
around 2.
RHCP coupling is done by the antenna itself. In facts, the H antenna
is 20 cm ahead the V antenna... this allowed me to opt for a simmetric
coupling solution: the quick and dirty lamda/4 75 ohm transformer.
The ideal distance would be 17 cm ### (300/436) / 4 ### but I dont
mind having a little elliptical polarization.


VHF
Both dipoles, when feeded separately, resonate perfectly between 144
and 145.5 MHz. Around 145.9 (the desired frequency) their SWR is
around 1.5.
The dipoles use two bazookas each about 50 cm long wich require RG-213
to be fittend in. N-Connectors (provided by Tonna) feed the dipoles.
Since the dipoles are only 10 cm distant from each other, this time I
had to phase the antennas using a delay line.
To implement such line I have fed the dipoles with two sections of
213, one 34 cm longer than the other ### ((300/145) * 0.66) / 4 ###.
So those two lines are 50 and 84 cm long.
On each line I connected PL-259 connectors and, trought double so-239
females, two sections of lamda/4 long RG-59. These 75 ohm sections are
intended to reuse the quick and dirty solution wich couples two 50 ohm
loads trought a triple female Tee-SO-239 connector.
Unfortunately after coupling SWR never drops below 3.


Now the questions:

How come that antennas intended for Satellite use resonate on
frequencies lower than satellite sections?
They dont have any kind of stub or other tuning device so will I have
to keep them just like they are?

I think my coupling solution for VHF is theorically correct. Isnt it?
Then why no resonance at all? Would the Tonna antenna coupler fix the
problem?

Is anybody else using same antennas? How did you couple the dipoles
for RHCP / LHCP and what is the SWR you obtained on satellite freqs?

Thanks for reading this.
Any kind of help would be highly appreciated.

Alain De Carolis
IZ6BYY, WW3WW

in the last weeks I have been fighting againts my two Tonna's crossed
Yagis: a 2x19 elements UHF and a 2x9 elements VHF.

I still cannot manage to have them up and running. Here are the
details of the story:

UHF
Both dipoles, when feeded separately, resonate perfectly between 420
and 426 MHz. Faston climps feed the diples (dont agree with this
solution but there must be a valid reason if they adopted them).
I have coupled them using two lamda/4 sections of RG-59. Each section
is 11.3 cm long... ### ((300/436) * 0.66) / 4 ###. They terminate on a
BNC wich goes on a Tee-BNC down to the RTX.

It has been a long time but I think when I put up a Tonna that 50 ohm coax
was used between the elements and the T . I know this does not make for
matching as normally 1/4 wave sections of 70 ohm coax is used in a 50 ohm
system. Not sure what the lengths were seems that differant lengths were
used for right or left hand circular but not very sure on that at all.