[TowerTalk] Why does KT34XA/KT36XA stink on 15 ?

[john at kk9a.com]

I seem to recall reading about 15m SWR complaints but not gain. The KT36XA
is a very complicated antenna. If it always acted this way for you perhaps a
component was out of spec. Many 40m beams are not resonate on 15 but I
believe yours is. Since it is 30 feet away and rotating does not have an
effect I am guessing that is not the issue but it's easy to model.

GL,
John KK9A


Steve London n2ic wrote:

I know I'm not the first one to observe this...

I have a KT36XA on one tower, and reference monobanders for 10, 15 and 20
on other towers. On 10 and 20, the XA always performs within a few dB of
the monobanders (sometimes, even better than the monobanders). On 15, the
XA is always down about 6 dB from the monobander. This is consistent
regardless of distance, direction, skip length, etc. Even the "band noise"
is down by this amount. The SWR on all 3 bands is reasonable. Long ago, I
also measured the resonant frequency of each element. See
http://www.kkn.net/~n2ic/kt36xa.xls . There is a 40 meter beam about 30
feet above it, but the 15 meter SWR does not change when either the XA or
40 is rotated, so I don't think there is significant interaction.

What did KLM/M2 do wrong on 15 ?

Before you tell me your KT36XA works great on 15, what are you comparing it
with ?

73,
Steve, N2IC