Topband: Quarter wave sloper ?

[Jim Brown]

On 7/27/2024 12:47 PM, jim.thom jim.thom at telus.net wrote:
> Has anyone had success with a 160m,  1/4 wave sloper....hanging off a 90'
> tower, with a 40m yagi just above the top of the tower ?

Yes, I've successfully used a sloping wire, suspended from a piece of 
large PVC conduit running horizontally through the tower at the top. I 
feed it against radials at the bottom, about 20 ft off the ground. N6BT, 
who has done a lot with verticals and elevated radials on 160, told me 
that they need to be near that height for reasonable efficiency. I've 
also added a dozen or so on-ground radials to the tower, which causes in 
to act as a passive reflector, yielding a few dB gain in the direction 
of the slope.

An important piece of advice -- if your sloper is shorter than a quarter 
wave, do NOT add a loading coil, just feed it with a decent RG-213/RG8 
size coax and tune it in the shack. Loss is quite low in that size coax 
on 160, but the feedpoint is a high current point, which makes it an 
important part of the antenna; a loading coil at that point eliminates 
part of the high-current, making the antenna a bit less efficient.

73, Jim K9YC