[Elecraft] [KX1 and KX3] QRP with AlexLoop while portable

[Doug Turnbull]

      For the past year I have been using the KX1 and KX3 portable running
QRP while using full length shock cord verticals and the AlexLoop.   The
following details my findings and surprise that the AlexLoop works so well.
For anyone travelling and forced to keep weight down the AlexLoop provides a
useful approach especially if you need to keep the antenna indoors or
inconspicuous.

     The great features of the AlexLoop are convenience, portability,
relative stealth and, most importantly, the antenna works.    The well-made
carrying bag is approximately 400mm / 15.5" x 290mm / 11.52 x 80mm / 3".
One can carry a KX1 and perhaps a KX3 inside with the antenna.   The weight,
including coax and case is approximately 1,600 grams or 3.6 lbs   Seldom is
there need for additional coax.

     For the past year I have used this antenna indoors and outdoors in the
USA, Ireland and Italy.  From both the USA and Ireland, it has helped make
QSOs across the Atlantic running 5W on CW using a KX1 or KX3.

	Set-up is accomplished with antenna tuner disabled.   Tune for
maximum noise, maybe in SSB mode rather than CW for greater noise; then to
fine tune, put out a few dits on a clear frequency and adjust for minimum
SWR.    In most instances I get down to 1.2 to 1.     Only in the presence
of steel reinforced walls have I used the built-in KX1/KX3 tuner.

      The SWR is 1.3 or lower on 40 meters through 12 meters but for me has
been excessively high (3:1) on 10 meters; perhaps the AlexLoop was not far
enough from metal objects while on 10 meters.

      Bandwidth is wide enough on 15M to leave the antenna set to the middle
of the CW band and never retune.    On 40 meters, retune the antenna about
every 20 kHz.    With the antenna beside the operator, this is convenient.


      The AlexLoop will not perform well near metal, be it steel reinforcing
in walls, springs in an easy chair, a stack of radios or electrical wiring
in a wall.  A power line to your transceiver is not a problem as long as you
do not drape it across the AlexLoop.  I have used the AlexLoop atop a steel
reinforced wall in Italy and found in this instance the need the need for
the KX3 antenna tuner once the AlexLoop was adjusted to frequency.  A number
of European QSOs were made with this arrangement but no North American QSOs
on this occasion.

      Shock cord whips at full quarter wave length without loading coils for
15M and 20M while using tow raised radials showed no significant improvement
when switching between vertical and AlexLoop.   This makes little sense, but
is my observation.  It is much easier to tune the AlexLoop to another band
than to adjust the vertical lengths.  For one thing you can do it at night
when the vertical is outdoors and the AlexLoop indoors.   The AlexLoop can
be used inside a frame house or concrete block building without steel
reinforcing.   Then there's no need to go outside and adjust the antenna.
Hotels with balconies ore outside terraces can also be useful locations. It
is convenience which convinced me to take only the AlexLoop on my travels.

     The meter diameter antenna does not arouse too much worry nor is it
likely to disturb neighbours with wires dropping down below their balconies.
I have had an Italian policewoman drive past me twice whilst operating on a
park bench in Monticatini Alto; she observed and just smiled.  The antenna
has even been carried assembled on a hotel elevator to the rooftop garden.
Small and light are major helps.

     The directivity is most useful in nulling local electrical noise, but
is far less evident as regards the received signal.  Do not expect great
front-to-back or front-to-side rejection.

     My favourite deployment for the AlexLoop is on a walking stick or broom
handle set in a tripod, but who wants to carry a tripod in aircraft luggage?
You do not need a tripod.   If your chair has no springs or metal in it,
then rest the antenna on the chair or against furniture. Do no place a metal
tube through the AlexLoop for support.  I have rested the AlexLoop against
concrete walls and extended it out beyond the wall tying the AlexLoop with
the supplied cord or dental floss.   The one meter diameter antenna is light
and easy to install.  Try to keep the antenna within arms' reach of the
operating position.   The AlexLoop site www.alexloop.com gives many examples
of installation.   I have rested the antenna atop shrubs and hung it from
branches.   Try to mount a meter above ground and forget masts.

     The AlexLoop is not Gotham Vertical, nor is it a G5RV thirty feet above
ground.   It does work though and whilst running QRP you can have many QSOs.
This antenna is for power of 20 watts maximum when operating SSB or CW- data
modes may require dropping to 10 watts.    I use the antenna on CW using
five watts.   I do not call CQ but look for stronger signals calling CQ or
in QSO for a call when the QSO finishes.  It is harder to rag chew, but such
contacts re enjoyed.  Some people get interested when you describe the
set-up. I never call with /QRP appended.   Some signals are so weak that you
are not likely to work them but can make QSOs and for me this is great fun.

     This 2014 CW WPX, the KX3 and AlexLoop were used for 197 QSOs on 40, 20
and 15 running 5 watts.   This was a casual effort with early to bed and
late to rise regime.   There were plenty of breaks for socializing, meals
and exercise.  The AlexLoop was inside my sister's Connecticut frame house
for most of this operation, with some periods outside on her patio running
from batteries.   I did not find much difference between indoors and
outdoors operation.  Strong European signals were easily worked on 15 and
20m.   Many west coast, South American and West Indies QSOs were made, plus
a few into Africa.  I heard Japan and Asiatic Russia but could not raise
either.   Europe was heard on 40M, but not worked; however a number of QSOs
up and down the east coast and into the mid-west were made on 40M.   I did
not work late into the night; concentrating on 20M during darkness.  Forty
did not get a fair shake.   The AlexLoop works on 40 and would work Europe
under favourable conditions.  Most of the European QSOs were made with the
antenna indoors a couple of feet from the radio.    Many cross Atlantic QSOs
have been made by EI2CN / KC1AV from both sides of the pond.

     The AlexLoop is not inexpensive, costing $300 plus $69 to ship to the
USA but this is a good price for an antenna which works and is both
convenient and portable.   Compare it to other antennas you will find the
cost looks reasonable.

There are other magnetic loop antennas available, but none I know of are as
portable.   You could of course make your own; finance is tough for many in
the hobby.   If you can put a G5RV up, then leave the AlexLoop for
problematic locations.

             73 Doug EI2CN and KC1AV