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HELP please AO40 RHC Crossed Yagi connections

Hi all,I am currently setting up for operation on AO40 but am a bit
unsure how to connect up a F9FT Tonna 435MHz 2 X 19ele crossed Yagi for
RHC polarisation.
Now both yagis on the boom are 50 ohms. The horizontal Yagi is
positioned 20cm in front of the vertical Yagi on the boom. 

What I think it needs to bring the impedance of the paralled antennas
(25ohms) back to 50 ohms is a 1/4 wavelength of 75ohm coax coming from
each Yagi to a T-piece (maybe use BNC connectors and BNC T 75ohm). Then
have a BNC plug to N socket adaptor so I can connect my 50ohm RG213/

  Now do I need an extra length of 50 ohm or 75ohm coax on the Yagi that
is spaced 20cm in front, to get the 90 deg phase shift or not ? If this
is the case Im going to have a lot of loss in connectors.

I have searched the net and books but cannot find any good examples on
phasing RHC yagis.

After sorting the above out what is a good 75 ohm coax for 435MHz TX
use. I have found a length of RG62AU which some websites and books claim
it low loss 75 ohm and other sites say it Ethernet style 93ohm. I guess
BNC connections would be the best choice as I can use the correct
impedance connectors to match the coax. Are T-pieces generally 75 ohm or
50 ohm or should I not worry.

Sorry for all the questions but trying to get the setup right. 
My downlink will be FT847 WITH DB6NT MKU24 downconverter to 144 with
G3RUH 60cm dish and patch feed. Hopefully I will get it sorted by the
time AO40 is fully running.
73s Darren G4VTQ

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