Do you need to be careful when turning antenna 90 degrees that your boom
is not a fundamental length of the band you are concerned about or you
might create other pattern issues?
W0MU
On 3/23/2021 9:08 PM, David Propper wrote:
Al,
I have had a 6 mtr beam mounted above my TA-33 tribander in several different installations for the past 40 plus
years. There has been no significant interaction between the two antennas (50 MHZ DXCC and WAS/WAC are the
proof…………DXCC Honor Roll on HF as well, all antennas never higher than 45 feet). The
6 mtr beam has been either a 4 or 5 element beam on a 12 foot boom. My rule of thumb has always been to mount the
6 mtr beam 5 feet above the tribander. If you need to mount the two meter beam on the tower, you could follow
Chuck’s recommendation below or extend the mast by coupling a smaller diameter mast to the top of your
existing mast. The two mtr beam has minimal wind loading, so shifting down to a smaller diameter mast coupled to
your main mast would be ok for the 7 element beam.
FYI, when you mentioned that you tuned the antenna on the ground, just how
close to the ground was the antenna ? Was it in a horizontal plane, or was it
tuned on the tower and the tower folded over, so that either a director or
reflector was close to the ground ?
Good luck and hope to hear you on 6 mtrs once the Sporadic E season starts.
73,
Dave, K2DP
St. Louis, MO
On Mar 23, 2021, at 6:00 PM, Chuck Dietz <w5prchuck@gmail.com> wrote:
Try the 6m perpendicular to the C3 to see if that helps. It could be placed
at the top of the mast for best separation and the 2m in the middle.
Chuck W5PR
On Tue, Mar 23, 2021 at 2:30 PM Al Kozakiewicz <akozak@hourglass.com> wrote:
Still have a foot of snow on the ground, so I'm not quite ready to climb
yet.
See photos on QRZ page.
I have 3 antennas on a 10' mast sticking a total of 8' out the top of the
tower. From top to bottom, 2M7, 6M3 and a C3, all equally spaced. All were
tuned to resonance on the ground.
Now up in the air, the C3 and 2M7 are fine, but the 6M3 is useless. The
SWR is about 3:1 and Z=~70 ohms at the minimum for both.
Is this symptomatic of interaction, i.e. feed point characteristics change
while resonance frequency remains the same? If so, what is a recommended
solution? The one possibility I haven't checked yet as it requires climbing
is a bad rotor loop cable.
Al
AB2ZY
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