This afternoon just before 75 died I was listening on 75 to a bunch of guys including W1IA. He flipped the phase on his antenna and I was shocked.
I only wish my SDR set up was turned on to get an accurate DB reading but it was well over 10 dB. I never tried the 135 degree delay line but I see by simulation the reason he went that way.....very cool!
Still testing, but after additional modeling with the feedlines we ended up at 90 degree delay.
The feedlines play a huge part in the model. I experimented with 70, 90 and 125. It came back to 90 degrees. Final numbers are 9.51 dBi gain with 15 dB front/back. Take-off angle is 45 degrees. It is amazing on the air; I agree with Gary...I am spoiled instantly.
Advice...stick with 1/2 wave feedline lengths. Antennas cut for 3.8 mhz. All feeders are tuned 1/2 waves at 3.8 mHz. I have 3 half-waves total into the shack and made for easier feedpoint impedances. Much smoother resistive component. Mark KA2QFX and I have been working on this system for 2 months now and will publish all the info soon.
In a nutshell: Antenna cannot be lower than 55 ft (model falls apart) Maintain 55 feet spacing. Use 1/2 wave multiples of feedline. Measure, measure , measure you cannot do this without an analyzer (MFJ or other) Tuning feedlines, antennas, stubs etc. If you don't hae an analyzer use the free TLD software by ac6la. This is dead on and you can calculate your feeders without an analyzer and be almost perfect.
Stayed tuned for addtional data....p.s. I have 1 uh of series inductance 500 pf shunt and add 500 pf more to move the antenna up to 3885 khz....Antennna cover from 3.5 to 3.93
Brent W1IA