Topband: 160m T-loaded vertical antenna

[w2pm at aol.com]

YC0LOW Writes:

>>

-----Original Message-----
From: Jo,YC0LOW <yc0low at gmail.com>


Last weekend, I finished installing the T-loaded vertical antena using 
the
18m Spiderbeam fiberglass pole. It has 3 wire spokes for top load, each 
at
15 meter long. Also, 3 elevated radials at 1/4 wavelength long in the 
height
of 3 meters each. The elevated radials are still bended here and there
according to my limited land-lot area. The SWR 1,6:1 at 1825 kHz. The 
lowest
1:1 is at 1800 kHz. I think I must pull out radials in 
straight-and-level
form to obtain the SWR match and resonance (at 1825 kHz) and will see 
if the
radial wires would need trimming.

I am using coax Andrew 7/8 inch about 21 meters in length as feeder 
line. My
shack is in the first (not ground) floor. So, both (coax and radials 
are
elevated). I am using home-made UNUN dual impedance (12.5 & 24 Ohms) a 
la
W2FMI

This is my first time to build vertical antenna for TX on topband. 
Would be
very grateful to hear any advises on what to do best to optimise the
antenna. TIA. Also, I'd like to express my gratitude to Bjorn, SM0MDG, 
for
his suggestions and guidance in making this antenna.

I hope I can continue to present YC-land on topband. 73 de Jo, YC0LOW


W2PM Replies:

Jo - how much better a match are you lookiing for with 1.6:1??  ALso, 
are you using a current balun choke at the feedpoint at the base? Very 
important to avoid losses with the raised radials and coax coupling to 
the earth unless they are high, over 15 ft.

73

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