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Remember that the two most common "verticals", the R-7 series by
Cushcraft and the DX-77 by Hy-gain are not 1/4 wave verticals. The R-7
is a 3/16 wl vertical and the DX-77 is a hybrid windom fed 1/2 wave
vertical.
I've found that both antennas work better if they are elevated to
minimize ground losses. I have found the R-7 and DX-77 to be excellent
performers when elevated at least 1/4 wl above ground, or even better
1/2 wave above ground on their lowest cut frequency. That's about 66'
or 1 full wl on 20M. I read W4RNL's piece to say that the radials made
a difference of less than 1Db over poor ground diminishing as the
existing ground improved (less lossy). Note that this observation was
for vertical dipoles that were virtually ground mounted. Dipoles should
exhibit less ground loss than verticals since they are electrically and
physically complete.
Both the R-7 and the DX-77 use a counterpoise to minimize ground losses,
not eliminate them. I would love to see a direct comparison of these
"radial free" verticals and a true dipole vertical. The Force 12 ZR-3
is a short vertical dipole that uses linear loading by means of rings
to achieve electrical and physical length. Even as short as it is, I
would not be surprised to see it perform better than a ground mounted
"radial-free" vertical.
I have done rather extensive on-the-air comparisons of the R-7 and the
DX-77 as compared to a tribander and a dipole, but the antennas were all
mounted above 150' in one test and above 240' in the other so they won't
track most installations. I did find that the vertical often gave me
better DX take-offs than the dipole and on some occasions better than
the tribanders. I expect that was due mostly to polarization. I, for
one, think they are pretty good antennas for what they are. Simple to
install and small real estate requirements providing you can get them up
at least 33' in the air which is about 1/2 wl on 20M. A push-up mast
works pretty well. Automatic band switching for seven bands in a
compact package makes an attractive package for the real estate
challenged. I even installed a R-7 on a 10' mast on the roof of my
house in a deed restricted community rigged with a gate hinge and
pulleys. I made a small saddle for the antenna to lie in while
horizontal to protect the upper capacity hat. At night I simply pulled
my line and I was on the air. It even worked while horizontal with my
FT-1000D's built-in tuner. My neighbors believed it was an elaborate
lightening system.
Now that I have no restrictions, I'm back to yagis and wire arrays, but
I still keep one R-7 or DX-77 up as an alternate antenna.
Jon Hamlet, W4ZW
Casey Key Island, Florida
"A little bit of paradise in the Gulf of Mexico"
--Boundary_(ID_UEhCjPvkYqDnPn+0dOjHwQ)
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<P><FONT face=Tahoma color=#0000ff size=2>Remember that the two most common
"verticals", the R-7<SPAN class=156230318-07032002> series </SPAN> by
Cushcraft and the DX-77 by Hy-gain are not 1/4 wave verticals. The R-7 is
a <SPAN class=156230318-07032002>3/16 wl </SPAN>vertical and the DX-77 is
a
hybrid windom fed 1/2 wave vertical.</FONT></P>
<P><FONT face=Tahoma><FONT color=#0000ff><FONT size=2><SPAN
class=156230318-07032002>I've found that b</SPAN>oth antennas work <SPAN
class=156230318-07032002>better if</SPAN> they are elevated to minimize ground
losses. I have found the R-7 and DX-77 to be excellent performers when elevated
at least 1/4 wl above ground, or even better 1/2 wave above ground on their
lowest cut frequency. That's about 66' <SPAN class=156230318-07032002> or
1
full wl on 20M</SPAN>.<SPAN class=156230318-07032002> </SPAN> I read
W4RNL's piece to say that the radials made a difference of less than 1Db over
poor ground diminishing as the existing ground improved (less
lossy). <SPAN
class=156230318-07032002> Note that this observation </SPAN>was for
vertical dipoles that were virtually ground<SPAN class=156230318-07032002>
</SPAN>mounted.<SPAN class=156230318-07032002> Dipoles should exhibit less
ground loss than verticals since they are electrically and physically
complete.</SPAN></FONT></FONT></FONT></P>
<P><FONT face=Tahoma><FONT color=#0000ff><FONT size=2>Both the R-7 and the
DX-77
use a counterpoise to minimize ground losses, not eliminate them. I would love
to see a direct comparison of the<SPAN class=156230318-07032002>se "radial
free"</SPAN> verticals<SPAN class=156230318-07032002> and a true dipole
vertical. The Force 12 ZR-3 is a short vertical dipole that uses linear
loading by means of rings to achieve electrical and physical
length. </SPAN> <SPAN class=156230318-07032002>Even as short as
it is, I would not be surprised to see it perform better than a ground mounted
"radial-free" vertical.</SPAN></FONT></FONT></FONT></P>
<P><FONT face=Tahoma><FONT color=#0000ff><FONT size=2>I have done rather
extensive on-the-air comparisons of the R-7 and the DX-77 as compared to a
tribander and a dipole, but the antennas were all mounted above 150' in one
test
and above 240' in the other so they won't track most installations. I did find
that the vertical often gave me better DX take-offs than the dipole and on some
occasions <SPAN class=156230318-07032002>better </SPAN>than the
tribanders.
I expect that was due mostly to polarization.<SPAN class=156230318-07032002>
</SPAN> I, for one, think they are pretty good antennas for what they are.
Simple to install and small real estate requirements providing you
can <SPAN class=156230318-07032002>get </SPAN>them up at least 33' in the
air<SPAN class=156230318-07032002> which is about 1/2 wl on 20M</SPAN>.<SPAN
class=156230318-07032002> </SPAN> A push-up mast works pretty
well.<SPAN class=156230318-07032002> Automatic band switching for seven
bands in a compact package makes an attractive package for the real estate
challenged. I even installed a R-7 on a 10' mast on the roof of my house
in a deed restricted community rigged with a gate hinge and pulleys. I
made a small saddle for the antenna to lie in while horizontal to protect the
upper capacity hat. At night I simply pulled my line and I was on the
air. It even worked while horizontal with my FT-1000D's built-in
tuner. My neighbors believed it was an elaborate lightening
system.</SPAN></FONT></FONT></FONT></P>
<P><FONT face=Tahoma><FONT color=#0000ff><FONT size=2><SPAN
class=156230318-07032002>Now that I have no restrictions, I'm back to yagis and
wire arrays, but I still keep one R-7 or DX-77 up as an alternate
antenna.</SPAN></FONT></FONT></FONT></P></DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2>Jon Hamlet, W4ZW</FONT></DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2>Casey Key Island,
Florida</FONT></DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Tahoma color=#0000ff size=2>"A little bit of paradise in the
Gulf of Mexico"</FONT></DIV></B></STRONG></BODY></HTML>
--Boundary_(ID_UEhCjPvkYqDnPn+0dOjHwQ)--
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