[TowerTalk] Vertical radial wires.....how many and length

Jim Reid kh7m@hsa-kauai.net
Sun, 13 Feb 2000 13:53:56 -1000

>     I need a little education from the group.  I have won an HF2V 
> 80/40 antenna at a raffle.  I have not worked with a vertical before 
> but in doing some research it has become obvious that a 
> significant amount of ground radials helps in performance.  

Here is some info,  from earlier TT posts:

> With a ground mounted radial system, it
> takes about 60 radial to make it play, but with raised verticals
> and radials, you can get by with as little as 4 radials and make
> the antenna play.  

Per the experience of some,  if the raised vertical is about
1/4 wave up,  then 8 elevated radials will essentially
equal the boost in transmit efficiency about as much
as 60 to 90 ground mounted ones,  or will recover about  4 to
5 dB of what would otherwise be lost to ground loss, "heat",
warming the worms,  etc.  

If mounted quite "near" the ground,  much less than 1/4
wave high,  then  four elevated radials should save
around  half the ground loss,  or 3 dB which would otherwise
be available to the worms.  120 or more radials,  on the
ground,  will supposedly recover "all"  the xmit power
which might be lost in the ground,  said to approach 6 dB
saving of total power.  Or,  said another way,  a ground
mounted vertical without radials,  will deposit about 75% 
of the available power from the rig into the ground,  for 
the purpose of diathermy for the worms! (More than
half the rig power to ground loss, as the vertical antenna
radiation resistance,  in ohms, will be less than  the 
ohmic loss of the coupled ground resistance.)

I have had verticals,  down to 40 meters,  raised up as high,
or higher than 1/4 wave.  But,  IMO,  a 40 meter dipole up
around 35 feet high, or so,  will "work" better;  at least it
seems to not be so sensitive to noise.

73,  Jim,  KH7M

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