There has been much written about the G5RV.
Unfortunately, much of it is incorrect. The claims of most commercial antenna
builders is simply fantasy. The record was set straight when the G5RV's
developer, Louis Varney published an article in the ARRL Antenna Compendium #1.
Unfortunately, most G5RV builders haven't paid much attention to Mr. Varney's
article. We did!
The original G5RV is an efficient, all band, antenna. It
is shorter than a full size 80 meter antenna. This makes it appealing to those
who have limited space. The G5RV will give good results on most bands with
minimum effort.
The RADIO WORKS' 'NEW G5RV PLUS'
embraces over the many copy-cat versions of the G5RV on the market.
First, I have added a Y1-5K, our precision, Current-type balun at the
transition between the balanced stub and unbalanced coaxial cable feedline. The
second improvement is the choice and length of matching stub and RG-8X feedline
combination. The matching stub is reactive on most bands. The reactive nature
of the antenna and stub makes matching difficult unless a wide range transmatch
is used.
Before purchasing this antenna, take a
look at the CAROLINA WINDOM. Unless you have a compelling reason for using the
G5RV, the CAROLINA WINDOM will give you far better performance on every
band. |
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After careful analysis, I changed the matching
system for the best compromise on all bands. A change in stub resonance and a
specific feedline length was necessary to achieve the best match on each band.
Still, the match is not perfect on any band. It is lowest on 20 meters where
the SWR drops to around 1.8:1 under ideal conditions. On all other bands, the
SWR will be higher. Even with a slightly elevated SWR, losses in the system are
low. Unless you are using a rig with tube finals which can accept a moderately
high SWR, a transmatch is necessary. This advice goes for any G5RV. Contrary to
what many antenna makers claim, the G5RV requires a transmatch unless your rig
can tolerate a moderately high SWR.
The Y1-5K, Current-balun keeps RF off the coax and reduces any
chance of RF feedback problems. Combining these technical improvements
with the G5RV's own attributes produces a very good antenna system. The RADIO
WORKS' NEW G5RV PLUS is an excellent combination of performance modifications,
high quality, and high power parts.
The reduced size of the G5RV is one attractive feature. A
second is multiband operation with coax feed. Coax is so much more convenient
than ladder line or open wire. Further, most modern transmatch circuits do not
work well when feeding reactive, high impedance feedlines. The G5RV does not
require a balanced output transmatch. This means that you can use the NEW G5RV
PLUS with nearly any transmatch, including those neat little 'automatic tuning
units' that some rigs have. One short caveat though, the SWR may get out of the
tuning range of the automatic tuners on some bands. It all depends on your
particular installation. |
