[VHFcontesting] Antenna stacking question

[Charles.Morrison@apcc.com]

When stacking vertically, the horizontal beamwidth remains the same.
When stacking horizontally, the vertical beamwidth remains the same.

On HF stacking vertically is used to gain a large "foot-print" of 
coverage.

On HF stacking horizontally is used for a narrow target. i.e. Japan from 
USA.
This is also used when a long-boom solution is needed but is physically 
not practical. 
The height of the array is determined by the predomiant propagation angle 
of the target distance and frequency.
Ex. USA 15M array to JAPAN @  ~70ft.
Ex:  Fixed 20M H-frame arrays of 4ele's are in use in EU/Russia to cover 
USA. ( W1 through W6,7.)

When stacking vertically, the VERTICAL beamwidth increases slightly 
compared to a single antenna.
A single 3ele may be 14degs (tall) at 7dbi,  but a pair may be 16 or more 
degrees (tall) at the same 7dbi strength.

On VHF, where skywave is of little concern, efforts are focused at the 
lowest angles ( high antenna heights )
and focusing the radiation. (0deg) 



Charles Morrison
ProStaff : Documentation Specialist at APC - East Providence
40 Catamore Blvd
East Providence, R.I. 02914 USA
Tel Ext. 6652
charles.morrison at apcc.com
Amateur Radio callsign: N1RR



"David L. Martin" <dlmarti at kc2lcf.net> 
Sent by: vhfcontesting-bounces at contesting.com
05/17/2005 09:21 PM
Please respond to
dlmarti at kc2lcf.net


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Subject
[VHFcontesting] Antenna stacking question






When you stack antennas you get a gain of a little below 3dB, twice the
antenna equals twice the signal.  Makes sense.

Do stacked antennas with a combined gain equal to a much longer antenna
have a wider beam than the longer single antenna?

You guys probably already know this, but I just recently began to
suspect it.  I would like to hear someone confirm or deny it.

-- 
David L. Martin <w0snj at arrl.net>
http://www.kc2lcf.net

There's a fine line between fishing and just standing on the shore like an 
idiot.


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