[VHFcontesting] 6m Array Switching

[Mike Clarson]

Ev/David: I'll have to check out the AO program. The 2.15 dB is simple
enough--Isotropic vs Dipole, and rightly belongs in an antenna prediction
program. Ground reflection, however, to me, belongs in a propagation
prediction program since it seems to apply equally to all antennas, it must
vary according to local conditions, and, it is just as likely to cancel the
arriving signal as it is to enhance it. Wisely, David cautions the results
due to "Ground Gain". None of this really applies to my actual situation as
I am lucky just to get one antenna in the air!--Mike, WV2ZOW

-----Original Message-----
From: vhfcontesting-bounces at contesting.com
[mailto:vhfcontesting-bounces at contesting.com]On Behalf Of Ev Tupis
Sent: Saturday, July 03, 2004 6:04 PM
To: VHFContesting eMail Remailer
Subject: Re: [VHFcontesting] 6m Array Switching


 > It only takes a few minutes to construct a model of this antenna in
K6STI's
 > AO program.
 >
 > All antennas:   14.14 dBi @ 7 degrees
 > Upper pair:     12.67 dBi @ 6 degrees
 > Lower pair:     11.84 dBi @ 12 degrees

> David: Is the "ground gain" a real number?

Hi Mike,
Gain is best understood as a relative (as opposed to an absolute) indicator.
What David cautioned me was to subtract 6dB for "ground gain" and 2.15dB for
"dipole gain".  When all is said and done, things end up looking like this
in
"reality" (whatever that is <smile>) -- including some information that was
on
the graphical plots that Dave (so kindly) sent me:

Dipoles at (1) 50'
            (2) 38'
            (3) 26'
            (4) 14'

Antenna       First---Lobe---Elevation   Gain @
Constellation -10dB    Max dB    -10dB   Lobe Max
------------- -----    ------    ------  ---------------------------------
(1,2,3,4)     3-deg    7-deg     15-deg  14.14-6-2.15=5.99 dBd
(1,2)         3-deg    6-deg     11-deg  12.67-6-2.15=4.52 dBd
(3,4)         4-deg    12-deg    34-deg  11.84-6-2.15=3.69 dBd

There are many aspects to a proper antenna analysis...the above is only
one...but it answers your question (I think).

Kind regards,
Ev, W2EV