[Antennas] 5-Band Quad VSWR

Thu, 2 Jan 2003 04:10:10 -0500

Dear Group,
During 2002, I purchased the Lightning Bolt retrofit kit and upgraded my
2-element (8' boom) quad to a 4-element (24' boom). The design is typically
for a single coax feed line through a balun, using a 150' run of LMR-400
coax from the tower to the shack. I was very careful to cut the wire loops
with precision to the specifications that come with the kit. When completed,
I raised it to about 65' and graphed VSWR readings on all 5 bands. My
concerns are that the readings are substantially increased over my old
2-element unit and well over 2.5:1 in some parts of the band. Previously,
the quad had excellent bandwidth with pretty flat SWR readings with
excursions not much higher than 1.5:1 with fairly decent directivity and
side lobe attenuation. With the retrofit 4-element unit, I now have to use a
tuner to get back to 1:1 SWR but this think kicks some serious tail.
Directivity seems unimpressive but I get through the nastiest dogpile on the
first few calls but because I am aware of the crappy VSWR, I will never be
satisfied until the quad can be tuned for a better VSWR. I have tried just
about everything but am open to helpful suggestions short of junking it and
going back to a manufactured tri-band beam.
Any ideas?
Walt KF2XN