[Top] [All Lists]

[TowerTalk] TH11 and Shorty 40, Revisited

To: <>
Subject: [TowerTalk] TH11 and Shorty 40, Revisited
Date: Fri, 6 Aug 1999 18:37:30 -0600
Hi Steve,
You didn't say how high the tower is.

In the ideal world, half of the signal will come from the incident wave
and half will come from the ground reflected wave.

The low band antennas MAY skew the pattern up or down some,
but one would assume that the amount would be almost identical
for whichever configuration you use.   Let us assume that with the
low band antennas above, the high band patterns are skewed DOWN
a few degrees.   With the low band antennas on the bottom, then the
high band patterns would be skewed UP, by approximately the same
number of degrees.  Net gain change would be nearly identical.

If the mast can support the low bands at the top, that is how I would
arrange them.  Most people need all the height they can get on the 
low bands.  On the high bands, lower is often better.  I find 80 to 100
ineffective over flat land on 10/15M during daytime conditions.  Lower is
better!  (40 to 60 ft)  At 110 to 120 ft, the second lobe on 10 / 15M
in the range of supportable angles so one gets both low and high angles
but with less pattern width in the vertical plane.

Hope that answers your question!

73,  Tom  N4KG

On Tue, 3 Aug 1999 16:03:01 EDT writes:
>In a message dated 99-08-03 13:37:14 EDT, writes:
>> It is highly unlikely that any high band elements will affect 40M
>>  performance
>>  when the booms of the high band antenna and 40M beam are parallel.
>>  This is due to the fact that all high band elements are less than 
>50% of
>>  a half wavelength on 40M.
>Hi, Tom --
>      Welcome back & tnx for your comments.
>      I have a question. For mast windloading purposes, I'm 
>mounting a F12 230/240 on the top of the mast with 12 foot spacing to 
>the 5BA 
>five-bander below it. Any (significant) problems with this proposed 
>configuration? My question has more to do with the bigger antenna 
>the lower antenna than the actual spacing distance (should be okay 
>to F12).
>Cheers,  Steve   K7LXC

Get the Internet just the way you want it.
Free software, free e-mail, and free Internet access for a month!
Try Juno Web:

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>