[TowerTalk] Two 15M stacking

TexasRF at aol.com TexasRF at aol.com
Sun Feb 25 09:29:43 EST 2007


 
One added thought that will help reconcile K1TTT's experience with others  on 
this subject:
 
>From K1TTT into Europe, say a 3500 mile path,  a 54 degree angle will  have a 
3dB coverage of about 3200 miles in width. From this part of the world,  that 
path would be about 1500 miles longer, encompassing about 4500 miles in  
width.
 
Yes, I can see that more antenna movement will be needed from New England  
for the same signal strength. Finally a factor that favors "the rest of  us"!
 
73,
Gerald K5GW
 
maybe In a message dated 2/24/2007 10:46:15 P.M. Central Standard Time,  
k5go at cox.net writes:

W4ZV:

Check the results in my link above
versus other MMs  using much larger systems...I don't
think you will find their much larger  antennas
make a significant difference.

Obviously you have a good  antenna system on 10M but (the real compliment 
follows, Bill) in my opinion  the VAST majority of the reason for your results or 
anyone else's results is  the operating ability as opposed to the 
effectiveness of their antenna  system.

You originally said:

My 6 element KLM array has a 3 dB  beamwidth of about 54 degrees, which is 
plenty for Europe.

There was  dispute from K1TTT, I think, who said that more than 4 or 5 
elements was too  narrow from the East Coast for Europe.  My example was to add food 
for  thought regarding a higher gain antenna and just how many degrees off 
you have  to be to have a weaker signal than with the original antenna.    

In my example I said suppose you doubled the boomlength and achieved  another 
3 dB which would narrow the beamwidth.  Doesn't matter it's a  little 4 
element 15M Yagi on a 24 foot boom or what.  My point was, that  in order to 
compare two antennas to know whether you could possibly lose  anything because of 
the narrow beamwidth, you would have to look at the 3 dB  beamwidth of the one 
with X gain and then compare it to the 6 dB beamwidth of  one with X + 3 dB of 
gain.  I have seen some compare the - 3 dB points  and say, for example, that 
because the 3 dB beamwidth narrowed by 20 degrees  that it is too narrow not 
realizing that they would still be nearly as strong  at the original beamwidth 
with the additional gain of the larger  antenna.  

I'll still take all the gain I can get pointed at  DL.

Stan,  K5GO
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