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Old March 8th 11, 06:13 PM posted to rec.radio.amateur.antenna
Wimpie[_2_] Wimpie[_2_] is offline
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First recorded activity by RadioBanter: Mar 2008
Posts: 329
Default Trap Vertical Antenna Questions

On 5 mar, 16:25, ka7niq wrote:
I have a tree here in the Tampa Florida area just begging to have a
Hustler 4 or 5 BTV stuck in it. I have had great luck with ground
mounted Hustler Verticals when I lived near the sal****er of Tampa Bay.
I am now in Brandon Florida, east of Tampa, and far from salt water. I
have stuck Hustler Verticals in trees before with radials for most
bands, but had access to a bucket truck back then, and did not have
stents in my heart. I got to thinking WHY not take a hustler vertical
with only ONE *Tuned "radial" for each band in the form of the lower
part of a 1/2 wave dipole. In other words, make the Hustler Vertical
into a multi band center fed 1/2 wave dipole. It will be a lot easier to
deal with only one radial for each band if they hang straight down the
tree vertically. Has anyone ever done this before ?

--
ka7niq


Hello Chris,

From another thread I concluded you have a flat membrane roof.

If you plan to use the 80/75m antenna for NVIS (local traffic) mostly,
why not putting a horizontal dipole above your roof. It will be very
likely below resonance length, but you can match this to 50 Ohms. This
will almost certainly result in better efficiency w.r.t. the
commercial vertical. For 40m and below, you can go vertical.

If you like to experiment and know the problems w.r.t. RF high
voltage, you may try a vertical resonating antenna that is in half
wave resonance. You will get end-fed voltages in the kV range, but the
common mode current will be significantly less w.r.t. a quarter wave
resonating structure. This reduces the requirements for your ground
provision and the ground loss.

What is the height of the tree that you plan to use as support (in
other words what is the maximum vertical height you can use)?

With kind regards,


Wim
PA3DJS
www.tetech.nl