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<H1><A name=top><FONT color=#ff0000 size=7
face="Times New Roman"><STRONG><U>Tony's Antenna
Corner</U></STRONG></FONT></A></H1>
<H1><FONT color=#0000ff size=5
face="Times New Roman"><STRONG><U>CONTENTS</U></STRONG></FONT></H1>
<UL>
<LI><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#6m-10m"><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">6m/10m Duo band mobile
whip</FONT></FONT></A>
<LI><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#4bandHF"><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">4 bander HF dipole
system</FONT></FONT></A>
<LI><A
href="http://users.picknowl.com.au/~wavetel/antennas.htm#2mdipole"><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">2m folded
dipole</FONT></FONT></A>
<LI><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#melrose"><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">6m "Melrose" 1/2 wave
vertical from coax</FONT></FONT></A>
<LI><A
href="http://users.picknowl.com.au/~wavetel/antennas.htm#lakeeyre"><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">"Lake Eyre" 40/80m
portable antenna easy errect</FONT></FONT></A></LI></UL>
<P><FONT size=3 face="Times New Roman">All These antennas have been constructed
and tried with good results. If they didnt work then I would not bother putting
them on here.</FONT></P>
<P><A href="http://users.picknowl.com.au/wavetel/antennas.zip"><FONT size=3
face="Times New Roman">Download all Antenna Diagrams Here as Zipped JPegs (file
is about 210k)</FONT></A></P>
<P><A href="http://users.picknowl.com.au/~wavetel/default.htm"><FONT size=3
face="Times New Roman">Back to Wavetel Main Page</FONT></A></P>
<HR>
<H2><A name=6m-10m><STRONG><U><FONT face="Times New Roman">6m/10m Dual Band
mobile whip</FONT></U></STRONG></A></H2>
<P><FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">This antenna has
been constructed using either a old CB whip or a 2m 5/8 whip stripped down. I
have been using it on my 4WD for years and had many good contacts. If you strip
down an antenna and heat srink it again then be aware that some heatshrink tubes
have a habbit of shifting the antenna resonance particularly when there are
helical windings involved. The former for L2 could be a peice of 20mm conduit
with a few adjustments. Build the antenna roughly to size and adjust the 6m
section first below L2 . Then move on to the 10m adjustment above L2
after.</FONT></FONT></P>
<H2><U><IMG src="http://homepages.picknowl.com.au/wavetel/6-10mmob.jpg"
width=524 height=944></U></H2>
<P><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#top"><U><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">Back to
Contents</FONT></FONT></U></A></P>
<HR>
<H2><A name=4bandHF><STRONG><U><FONT face="Times New Roman">VK5AH -HF 4
Bander</FONT></U></STRONG></A></H2>
<P><FONT face="Times New Roman"><STRONG><U><FONT
style="FONT-SIZE: 13.6pt">Construction Tips:-</FONT></U></STRONG><FONT
style="FONT-SIZE: 13.6pt"><SPAN class=Apple-converted-space> </SPAN>None of
the dimensions could be said to be critical except perhaps the 80m Tips (B) and
the G/H spacings. Build the Antenna complete before adjusting or trimming
anything. The Antenna was erected at about 25 feet in reasonably free space in a
horizontal plane. Dimensions would differ in a sloping configuration and extra
ropes may be needed from the bottom of the spacer conduits to the ends of the
inductors perhaps. Feed the antenna with a 1:1 balun and be careful the common
feed points dont get twisted up near the balun. The coils are not critical. Half
a dozen turns here or there wouldnt be critical but would tend to affect the 80m
tips a little. The resonant frequency will tend to drop typically 20-30 Khz on
both 80 and 40m when the coils are soaked in rain. They could be sealed perhaps
with polyresin but be careful they dont become too heavy. The spacer conduits
were drilled through and threaded onto the A section and held in place using
cable ties to stop it from sliding along the wire. The coils were wound with
fine stranded insulated wire of about 2mm total thickness (insulation included)
. The important thing is to be able to get that many turns onto the former close
spaced.</FONT></FONT></P>
<P><FONT face="Times New Roman"><STRONG><U><FONT
style="FONT-SIZE: 13.6pt">Adjustment:-</FONT></U></STRONG><FONT
style="FONT-SIZE: 13.6pt"><SPAN class=Apple-converted-space> </SPAN>Start
by adjusting the 40m sections (A) and then the 80m tips (B) then adjust the 20m
section followed by 15m lastly. Be careful to make all adjustments so as to keep
the antenna symetrical particularly the 80m tips. As a guide the 80m tips will
adjust at about 40Khz per inch and the A section will adjust 40m by about 10Khz
per inch. The 20 and 15m legs have little effect on 80 or 40 but the 20m legs
will effect the 15m section. Do not be tempted to bring the 15m sections up
closer to the 40m section as strange things start to happen on 15m. Dont be
decieved adjusting the 15m legs. The SWR will appear to drop nicely at about
20.8 Mhz but this is in fact the 40m section coming into play. If problems are
encountered making it work on 15m then disconnect the upper section of the
antenna (A) from the balun but leave it physically in place. Then adjust the 15m
section and finally reconnect the upper section. The SWR will rise slighly on
reconnection and the best you will get is about 1.6:1 SWR . My solid state
radios seem quite able to still deliver 100 % power forward into this sort of
load.</FONT></FONT></P>
<P><FONT face="Times New Roman"><STRONG><U><FONT
style="FONT-SIZE: 13.6pt">Performance and
Characteristics:-</FONT></U></STRONG><FONT style="FONT-SIZE: 13.6pt"><SPAN
class=Apple-converted-space> </SPAN>The antenna performs as a standard
dipole on all bands except 15 and 10m. It has a bit of end fire on 15 and 10m
making the antenna work almost omnidirectional. Particularly so on 15m due to
the 1.5 wavelength section from 40m The Bandwidths of the 2:1 SWR points is as
follows on each band.</FONT></FONT></P>
<P><FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">80m - 40 Khz,
40m - 250 Khz, 20m - 500 Khz, 15m - 21.0-21.350</FONT></FONT></P>
<P><FONT face="Times New Roman"><STRONG><U><FONT style="FONT-SIZE: 13.6pt">Other
Bands:-</FONT></U></STRONG><FONT style="FONT-SIZE: 13.6pt"><SPAN
class=Apple-converted-space> </SPAN>I have not tried the WARC bands but the
antenna seems to work reasonably well on 10m using a tuner. The SWR without is
about 5:1 .</FONT></FONT></P>
<P><FONT face="Times New Roman"><STRONG><FONT
style="FONT-SIZE: 13.6pt">160M</FONT></STRONG><FONT style="FONT-SIZE: 13.6pt">-
Try adding about 6.9m to the 80m ends and it works on 160 . I used some aligator
clips near the 80m end Egg insulators to clip/unclip the 160m sections as i can
get my antenna ends up and down fairly quickly on pulleys. The antenna adjusts
on 160m at about 3Khz Per Inch.</FONT></FONT></P>
<P><IMG src="http://homepages.picknowl.com.au/wavetel/5ah4band.jpg" width=924
height=455></P>
<P><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#top"><U><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">Back to
Contents</FONT></FONT></U></A></P>
<HR>
<H2><A name=2mdipole><STRONG><U><FONT face="Times New Roman">2m Folded
Dipole</FONT></U></STRONG></A></H2>
<P><FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">This folded
dipole has a 200 ohm feedpoint providing a good match for 50ohm coax through the
4:1 coaxial balun shown. The feed impeadance is achieved by making one side out
of a thinner conductor (2.5mm square building wire) .The SWR is very low across
the band. This antenna has been in use on the Adelaide 10m repeater, 2m
gateway.</FONT></FONT></P>
<P><IMG src="http://homepages.picknowl.com.au/wavetel/2mdipole.jpg" width=742
height=578></P>
<P><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#top"><U><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">Back to
Contents</FONT></FONT></U></A></P>
<HR>
<H2><A name=melrose><STRONG><U><FONT face="Times New Roman">6m 1/2 wave Melrose
vertical</FONT></U></STRONG></A></H2>
<P><FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">This half wave
vertical is made from coax. Both RG8 and RG58 is used. Pull out the inner
conductor of a length of RG8 and whilst doing this pull through a length of RG58
in its place. The coil can be adjusted to shift the centre frequency of the
antenna. Just take turns off to shift the frequency up or add turns to shift it
down. I have put my own antenna into a length of 40mm plumbing pipe. I made this
antenna up whilst on holidays in a place called Melrose so its called a
"Melrose" .</FONT></FONT></P>
<P><IMG src="http://homepages.picknowl.com.au/wavetel/melrose.jpg" width=665
height=956></P>
<P><A href="http://users.picknowl.com.au/~wavetel/antennas.htm#top"><U><FONT
face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">Back to
Contents</FONT></FONT></U></A></P>
<HR>
<H2><A name=lakeeyre><STRONG><U><FONT face="Times New Roman">40m/80m Lake Eyre
Portable</FONT></U></STRONG></A></H2>
<P><FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt">I made this
antenna up while camping near Lake Eyre. It was a great improvement on the
mobile whip. It just clips onto the mobile mount instead of the whip, the other
end is hoisted up into a nearby tree or support. I have generally used the
antenna at a 45 degree angle as a sloper. The coil is essentially a RF choke
like the 4 Bander dipole design. Try adding about 6.9m to the 80m ends and it
works on 160 . The antenna adjusts on 160m at about 3Khz Per
Inch.</FONT></FONT></P>
<P><A name=lakeeyre><IMG
src="http://homepages.picknowl.com.au/wavetel/lakeeyre.jpg" width=664
height=956></A></P></SPAN></DIV></DIV></BODY></HTML>