2 Operating Positions For Testing

....... "Typical Portable Site"...... and ...... "Worst Case Site" .......

POSITION #1: Typical Portable Site:

Operating Portable  has always been popular amongst ham radio operators, but for many hams today, it is out of necessity.  
  • Home Owner Association rule and regulations make it impractical or even impossible for many OM and YL to even get on the air from home.
  • Many hams live in appatment buildings with no possibility of installing an outdoor antenna.
When operating portable in the field, one usually has a less than perfect ground.  REASON:  unless it is going to be a longer operation, people typically just don't bother to do much, other than driving a simple ground stake into the ground - if they do anything at all.

 

I chose what I think might be a typical operating position, based on my 25 years of experience travling by motorbike and setting up the station in a tent. 

 

The Typical Portable Operating Position chosen was directly beside the antenna pole (or mast), directly under the antenna.

 

POSITION #1:
Typical Portable Operating Position.
  • The table is positioned directly next to the pole.
  • The ground stake is right beside the pole.
  • The coax is run straight down the pole which keeps it equal distance from the two legs of a symmetrical dipole.
  • This is only 100% symmetrical when nothing is influencing eather side of the dipole more than the other side (e.g., a garage, a parked car, another antenna, etc.).

 

The length of the coax depends on the height of the antenna's feedpoint on the pole.

For my tests I used 11m for the dipoles and 12m for the OCFD antennas.

 

In theory the extra meter of coax will skew the measured results slightly, but in practice, assuming CMC is much worse on the fundamental frequency than on the harmonic frequencies, 1m of coax on 40m will not make a significant difference.

 

POSITION #2: Worst Case Operating Position

 

to be continued...