17-01-2018, 09:20 PM
Hi Jayson.
That is how I have traditionally fed my yagis, from the DE over the back of the reflector then under the boom. On my old yagi I used three clamp on ferrite cores, which I think were not enough when I did it.
The distance between the DE and REF is 164mm which means I can theoretically fit 5 on there before the bend over the reflector. I could try that, or just see if they will go around the bend.
I have had limited success with the pawsey stub when I have tried to make it. I don't think the 1/4 stub is technically a "pawsey stub". I won't be mounting to the shield of the coax, only the boom, which I guess, is technically grounded if you have a good low impedance ground through the antenna mast clamps, mast, rotator, tower etc.
I have had static issues in the past with split dipoles on my yagis, thus one reason for going the LFA. I simply think the 1/4 stub does exactly the same thing, only that it has to be a 1/4 wave length for it to not affect the impedance at the feedpoint, adding losses too. I'm not so sure it's classed as a balun either.
The role of the ferrites will be to stop common mode current radiating down the coax line, forcing it to go back out the DE (if it is asymmetrical).
The ferrites you have chosen look good, they should work well.
Regards
Hayden
That is how I have traditionally fed my yagis, from the DE over the back of the reflector then under the boom. On my old yagi I used three clamp on ferrite cores, which I think were not enough when I did it.
The distance between the DE and REF is 164mm which means I can theoretically fit 5 on there before the bend over the reflector. I could try that, or just see if they will go around the bend.
I have had limited success with the pawsey stub when I have tried to make it. I don't think the 1/4 stub is technically a "pawsey stub". I won't be mounting to the shield of the coax, only the boom, which I guess, is technically grounded if you have a good low impedance ground through the antenna mast clamps, mast, rotator, tower etc.
I have had static issues in the past with split dipoles on my yagis, thus one reason for going the LFA. I simply think the 1/4 stub does exactly the same thing, only that it has to be a 1/4 wave length for it to not affect the impedance at the feedpoint, adding losses too. I'm not so sure it's classed as a balun either.
The role of the ferrites will be to stop common mode current radiating down the coax line, forcing it to go back out the DE (if it is asymmetrical).
The ferrites you have chosen look good, they should work well.
Regards
Hayden