[50mhz] Re: antenna stacking question

[Anthony W. DePrato]

At 11:30 AM 7/12/2006 -0500, dpease at adams.net wrote:
>I agree with JV, BUT, we had a 5 element 6 meter yagi on a 16' boom only 
>3' above a 5 element 10 meter yagi on a 24' boom and it really worked 
>well!  I am not saying the spacing didn't affect the pattern, but it still 
>worked well.  My guess is your a reason for asking about the close spacing 
>has to do with mast length or loading.  I suggest go with the most spacing 
>you feel you can get by with.  I asure you it will still work plenty of 
>stations.
>JV writes:
>>
>>      All beam antennas should be 1/2 wave above the lower frequency to
>>achieve max low angel take off. The closer the antennas are, the more
>>vertical the signal becomes. I would place the antenna no less than 1/4 wave
>>apart. JV


all this is true and they will work but if you check the books try bill 
orr's book you will find that you need the H and E planes to just touch for 
max gain when you stack say two 2 or 6 meter ants. for six meters if i 
recall would be 49 ft. that is why the stacked 11 element array Cushcraft 
had years ago for FM did not work well had too many side lobes. but when 
you spaced it out to about 12 ft it worked like gang busters..as for a 6 MT 
ant above a say tribander. i think you need to be a half wave at the top 
ant freq. as the tribander will look like ground to the six MT beam. they 
will work even if you put them 6 inches above the other but for max pattern 
performance go with a half wave
73 Tony wa4jqs