"Richard Harrison" wrote in message
...
Reg, G4FGQ wrote:
"Naturally, laboratories can differ one from another."

A lab may put its stamp of approval on your instrument, but your best
assurance may be measurement of known values. The temperature of
ice-water or the voltage of new dry cells, for example You usually can
try several dry cells for confirmation or averaging.

In antennas, one strategy for successful gain determination is
comparison with an antenna of known gain.

Whow, thats a good idea, write it up for QST. They are looking for pearls of
wisdom
that can be useful for ham radio operators so that we may maintain our
perceived
leadership of the art of antennas......'Compare with a antenna of known
gain'...... Revolutionary!
Now why hasn't any Guru on this group thought of this before today?
Now we have to decide what we use to measure the gain and more important
not to compare or to compare at a single recieving point especially if the
receiving depends
on skip or propagation. Is it possible that Guru's are unaware that
elevation angles
can be different when comparing antennas? Another gem for the ARRL and
provided
solely by the leading gurus of AMATEUR radio operators no less. Ofcourse we
need
a telephone link with the country that we wish to hear the transmission,
some thing on the simple lines of
....."can you hear me now"
question as we switch antennas
between a dipole and a drape / curtain array every 5 minutes

Art

To determine the gain of a SW BC curtain antenna, we hung a 3-wire (to
match 600-ohms) folded dipole alongside and at the same height as the
curtain. We swiched transmission back and forth every 5 minutes between
the dipole and the curtain. We continuously measured and recorded the
signal strength for several days in the target area. We averaged
strengths of each signal and compared them for periods of the
recordings.

The HF dBd of the curtain agreed very well with that measured on the
model at 400 MHz in the lab before the curtain was built at full scale.

Best regards, Richard Harrison, KB5WZI