Big fan of direct fed !
Agreed, the loss is low in most matching devices, but still....
there is...so if always wondered why anyone would see the "need" for it ?
Besides that i really dont think it is needed, i honestly think more then 75percent of all failure in CB yagi's lies within the matching device, perhaps thats whats in my mind....
Lets put it otherwise....give me 1 GOOD reason as "user" to use any matching device ?
The "downside" is, you can not "adjust" a yagi that much.
That most likely (in my opion) is one of the reasons manufacturers like to use a gamma-match / hairpin or whatever....it allows "failure for the manufacturer".
You know if you have a direct fed yagi, and the SWR isnt accurate....there is something going on. With all those other yagi's they all keep explaining how to adjust the matching system. Why adjust ? .. It shouldnt be adjusted...or at maximum, agreed... marginal adjusted.
If the antenna is free up in the air, it should be 1;1 no questions asked.
If it isnt..it should ring a bell.
Again, there is absolute no need for it.....(gamma-match etc)
There are a couple things you can do:
1- Direct 50 ohms, most likely this would be an owa style yagi
(roughly 5.5...6 meters boom 5 elements just below 10dBi just above 20..25dB FB is the most known example).
You could do.....with just 4 elements on that boom, with roughly the same figures, but it will be low impedance and narrow banded.
2-Design a 12,5 Ohm impedance yagi and add a folded dipole.
Thats the link you are refering to Marconi
(its a folded dipole not a bend radiator as your pdf provides).
3- design something in the 20 ohm regions and bend the radiator backwards
(k6sti V-radiator)
There are so many ways to go....
The only thing you can put on and will need is an RF choke.
RG 213, 5 turns 10cm diameter ( other diameters and numbers are not correct)
And you are good to go for as much power as the RG213 can handle.
Almost forgot...Sirs: ...shockwave&marconi, Not sure if there was a point, but agreed, there is no gain in CMC in aspect to a bent radiator..in fact the opposite would be more creditable (?) (due to change of angle in time) .
hope it was of use, 73 H/.
73 Henry.
