[TowerTalk] Re: 5el-20m KLM monobander-High SWR

[DF3KV at aol.com]

Dale, VE7SV wrote:

Hello Dale, 

you wrote very interesting stuff concerning my problem

> 
> 
> 
> The top one was installed across the face of the
> tower at 120' with no other antennas on the tower and after
> installation showed minimum SWR at approximately 14.350.
> This was confirmed with a MFJ antenna analyzer.

so it went up from the original frequency as well


> 
> The 2nd 5 el KLM was then installed across the face of the tower
> at 60'. It also shows a minimum SWR at approximately 14.350.

so no influence with each other, same as my 204BA



> 
> We were using RG213 to feed each antenna thru homemade 4:1
> coaxial baluns. These were replaced with KLM baluns but this made
> no difference.

same here...


> 
> This system has been in use for several years here and I have just lived
> with the high resonant frequency of the array but at the prompting of VA7NT
> we have decided to try and lower the system resonant frequency. Hence
> the question of a few days ago.

the tubings are probably not long enough to suffently lengthen the elements 

what do you think of my theory of capacitive loading of the driven element
by the towerface?
If so, it could probably be compensated by a coil (like betamatch-theory)


> 
> Your response does make me wonder about the effect of the tower.
> At some point we may attempt to retune our antenna's so please continue
> to post your findings to the reflector.

Perhaps I have to postpone that to spring, as I have other antennas to be 
prepared 
for the WWDX and the lowband dx-season. ( 3° centigrade only already)
But my plans are for a 4 high stack of those yagis, the upper two rotatable
and the lower two fixed to the US, sidemounted to the tower, fed as two 
hardwired stacks
with a homemade BLU-relaybox.Even the tower will not be finished this year, 
this single
yagi problem makes me nervous if thinking about the problems approaching with 
the stack..

I hope to get some more feedback from this reflector until then and 
experiment a bit to solve that problem 

73
Peter