For One and All,

A common Question Asked by many Shortwave Listeners
(SWLs) concerning Vertical Antennas is :

How High will my Shortwave Listener (SWL) Quarter Wave Length
(1/4 WL) Vertical Antenna Need To Be ?
http://groups.yahoo.com/group/Shortw...a/message/7157

Shortwave Meter Band and Quarter Wave Length
1/4 WL Vertical Antenna Height :
120 Meter = 97.5 Feet
90 Meters = 70.9 Feet
75 Meters = 59.2 Feet
60 Meters = 47.7 Feet
49 Meters = 38.5 Feet
41 Meters = 31.8 Feet
31 Meters = 24.5 Feet
25 Meters = 19.7 Feet
22 Meters = 17.1 Feet
19 Meters = 15.1 Feet
16 Meters = 13.2 Feet
13 Meters = 10.8 Feet
11 Meters = 9.1 Feet

For the 120M to 60M Shortwave Bands the Coax Cable
Feed-in-Line can be Equal to the Height of the Antenna.

For the 49M to 11M Shortwave Bands the Coax Cable
Feed-in-Line can be Twice the Height of the Antenna.

TIPS - For the Shortwave Listener (SWL) :

The Longer (Higher) the Verical Antenna the Better.
With 50, 60, 75 and 100 Feet being OK - Provided that the
Feed-in-Line is of Equal Length. This gets the Vertical
Antenna away from the House and helps to reduce the
Man-Made Noise pick-up from the structure itself.

Remote Ground Rod.
With Vertical Antennas Grounding is very important.
Placing a Ground Rod (and several 1/16 WL Radials
if needed) at the Base of the Vertical-Up-Leg of
the Antenna is a good construction technique.

Bury the Coax Cable.
Common Mode Noise can be a real problem with Vertical
Antennas and Burying the Coax Cable can be the First
Step in Reducing this Noise Source. Or use a Snap-On
Ferrite Core at each end of the Coax Cable.

Matching Transformer.
For a Multi-Band (All-Band) Vertical Antenna a 9:1
Matching Transformer (UnUn) can provide broadband
matching for 500 kHz to 30 MHz.

Trees as Vertical Antenna Support Structures.
For that Long Tall Vertical Antenna Trees are good
Vertical Antenna Rigging Structures for the Top-End
Mounting Point. Normally Tree Limbs are used as
the actual Mounting Point and the Tree Trunk itself
is not use. Try to use a Tree Limb that is at least
2"-3" Thick. Locate the Mounting Point about 3 to 5
Feet Away from the Truck of the Tree. Making the
Mounting Point Mechanically Strong with little
physical movement of the Wire Antenna Element.


hope this helps - iane ~ RHF
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/