[Elecraft] Less Than Perfect Antennas [was Flumoxed]

[Bob McGraw K4TAX]

For what appears to be a modest antenna installation, look at the 
obtained results  of KE4PT.   Where on QRZ.COM he writes;

""At home, my Icom706mkIIg pushes 100 W through a coax-coil + ferrite 
current choke to an AH-4 automatic tuner unit at the bottom of a 4.3 m 
tall, 14.6 m long dual element inverted L that is strung in the attic of 
my one-story home [/QST/, Oct. 2007, pp 33-37]. The antenna covers 160 m 
- 6 m. It's a modest station, but good enough for///WAS-TPA/,/WAC 
[8-bands]/,/DXCC [225 cfm]/, and/6m-VUCC/, and to copy HAARP lunar 
echoes on 6.7925 MHz with "/no visible means of antenna/". I'm always 
looking for Asian stations hidden behind the Auroral "ion curtain".  I 
enjoy chasing DX. The extra 17 dB that CW has over SSB helps with my 
modest station, so please look for me at the CW end of the HF bands!""


Yes, what appears as a modest antenna works, and becomes a good bit more 
than modest when correctly designed, installed and operated as Kai, 
KE4PT explains.   Wire antennas do work.  They are the least expensive, 
easiest to construct, easy to erect and they do work.   Yet many hams 
seem to think there is some "magic" to many of the various designs.   In 
fact some of the commercial antenna designs are just "lousy" antennas.   
   One often hears that  "a bla bla is a great antenna".  Well maybe so 
to them, that is until they encounter a true great performing antenna. 
And that great antenna is one which usually does not try to defy the 
laws of physics.

Thus a basic 1/2 wave center fed wire, cut to the electrical length for 
frequency/band of choice, and fed in the center with good quality low 
loss 50 or 75 ohm coax and erected in the clear as possible and as high 
as possible is one of the best performing simple and certainly not a 
mediocre antennas.   Of course it is a single band antenna.  Buy that 
fact!  I do suggest a 1:1 current balun at the feed point and unless the 
coax feed is perpendicular to the antenna, a good common mode choke at 
the station end of the coax is advised for resolving most Common Mode 
Current issues.   Common Mode Currents are not caused by SWR as some 
seem to believe.

As I have the space, my antenna of choice is 250 ft of #10 THHN in the 
air.  {There is no need to strip off the insulation and a choice of 
white makes it darn near invisible}.  Otherwise, space lacking, one can 
use a length that is about 1/2 wavelength at the lowest frequency one 
desires to operate. 80/75M = 125 ft, 40M = 66 ft, 20M = 33 ft. etc. To 
make it a multi-band antenna, change the feed line to 450 open wire, or 
450 window line, or 300 ohm window transmitting line, and feed it with a 
1:1 current balun and a wide range antenna tuner.   Just keep the coax 
between the tuner and the balun as short as practical.   Mine happens to 
be about 24 inches as I bring the balanced line from the antenna feed 
point all the way to the balun and tuner at the operating position.   {A 
balanced feed system is really easy to use and install and, not as about 
99% of the hams will say, it is asking for trouble.  Most that say this 
have never actually used one but are only repeating what others have 
said.  I've used balanced feed on at least one or more antennas at every 
station location of mine for the past 58 years.}  My K3S ATU and/or my 
KAT500 ATU will put this antenna on any frequency from 1.8 MHz to 52 MHz 
with less than 1.3:1 SWR.

And I do agree with Kai, KE4PT that CW offers about a 12 dB advantage 
over SSB.


73

Bob, K4TAX