Since October 2016 i use now bigger tower, so higher system but the original placement of the sloper doesn’t allowed me to lift ants up than 13m high.
So after 1 mounth of test , i have at least found a solution to have my tower completely pulled and a 160m system with a kind of half sloper working.
Since 2013 ,for the Top Band , i use a Half Sloper originaly based on wd8dsb design but i have rectif it to some European dimensions and materials.
So since Jully 2013 , i use my « version 4 » , definitiv antenna design : with some 2.5mm² wire, coil 71 turns on 40mm PVC pipe + 19.4m slop wire until 1.5m ground on a insulate support.
Nice SWR curve , 45Khz SWR under 1.5, 110Khz SWR under 2, 180Khz under 3 SWR.
Tower need radials, i have add arround 30, lenght between 10 and 20m longs and do not forget that beams on the tower upper the sloper act as Hat-cap.
Coil should be 40-44uH and arround 500Ohms react. So theorical value est near pratical value.
I have begin this antenna the 20 Feb 2013 and at 16h local time , the antenna is on tower , I ve begin with 80 turns on the coil @14.5m gnd and + 20m slop until 1.5m gnd :
with 1.5mm2 on coil : 1620Khz / 1.2SWR .
.. So i’ve redesign the antenna , it was my « 1st Prototyp » .
So now need to found the good compromise with numbers of turn in the coil and lenght of the sloper wire to change Z and X.
During tests ,40 radials, 10-20m longs are connected to the tower and grounded.
I will try 70 turns and cut 50 cms of the sloper …
RX is a bit noisy but gain is here, i ve done a french QSO on 1843Khz with ATU of the 756P3 cause Z is 13 Ohms … so 3.2 SWR.
24 Feb 2013, Sloper is QRV… on band but 1.9 swr 1850… Z:27Ohms, X … high ! Too much capacity with slop wire.
1795Khz 1.1 swr Z: 41 but snow is falling , must found a new solution… carbon in matching coil can have an effet…time to try…
27 Feb : so after few adjust 1.2swr 1820Khz , 68turns + 19.2m sloper untill 1.5m gnd… seems on good ways … but still some SWR, R 32 , X : 10. Must have a look reactiv and capacity.
28 Feb 2013 : New coil with less carbon, 65turns + 19.2m sloper untill 1.5m gnd 1.16swr 1840Khz .