I can't speak to the possible problem with the KT 34XA in the tri-bander
tests. The KT 34XA must be assembled correctly and tested for correct
operation and this is not often easy due to the connections that K6LL
mentioned.
I do want to correct one point. The KT 34 and KT 34XA were a big break
through on tri-bander design. K6MYC applied the Oliver Swan Log cell design
to to build a Tri-bander that shows low SWR across all of 20 and 15 and 1
Mhz of 10 meters. The log cell has gain by itself over a dipole(you can
refer to his notes in 73 and ham radio magazines) add to this parasitic
elements on the KT 34 and you had the best tri-bander on a 16 foot boom in
1979. Competitors used something similar (TH7, TH11, X-7, X-9). Adding
two additional directors for 10 and one for 15/20 and making them near
optimum in spacing made the KT 34XA a real break through in big tri-banders
24 years ago. A couple of hams added two more directors on 56 foot total
boom lengths with great success. KLM decided there was not enough market
for this and stayed with the 32 foot boom 6 element version.
When KLM folded K6MYC again took over the design and made the improvements
to mechanical problems (mainly connections) that correctec the problems that
plagued the beam. Most who have upgraded or modified their beams find
better gain and front to back on each band. One 36XA owner in Florida says
its just feels better and another tells me the new design overcomes some
problems with 15 which was the weak link in the compromises thast appear in
all tri-banders. When I got my KT34X (the early XA) I replaced 5 element
KLM Big Sticks for 10/15/ and 20. My 34X outperformed the original stack on
10 and was at least the equal on 20. On 15 the compromise was mainly a
lower than expected front to back (maybe 10 DB or so).
M2 (K6MYC) would like to add 17 and 12 to the KT36XA as those like myself
work band countries and it would be nice to get the same results on those
bnads. It look like that is the place where 4 elment SteppIR beam has a
large advantage over the KT34/KT36 series.
The weakness of the C 31XR is its only 3 elements on 20 and with the
sunspots in decline 20 will be carrying more of the DX and Contest load. If
you have the room and the tower the C 31XR's big brother is a killer even
against the mon banders.Beside the 31XR.
Which is best...depends on your location. Paul N4PN (they also use NF4A in
contests) finds that a big tri-bander, 2 el 40 meter beam, and various
antennas for 80 and 160 work as well at his place as the big stack he left
in Atlanta and even the big antennas at N4RJ (9 TOWERS!!). His St. Georges
Island Florida QTH feels like a Caribbean location and sure plays like it.
The SteppIR is really the first real break through in tri-band design since
the KT 34. Only time will tell if the fixed boom length will limit its
optimum gain and front to back. The early results are encouraging.
73 Dave K4JRB
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|