Here is some more practical info for you.
Just yesterday I finished putting up a 135' doublet. I am in a new QTH
that prohibits towers and the like, and am just now getting back on HF
after about a 10 year absence. The antenna is currently in a
"temporary" location in inverted V configuration with the apex at about
15' above the snow (we have 10-12 feet of snow on the ground here near
Lake Tahoe) and the ends at about 8'. I feed it with 100 feet of 450-ohm
ladder line. The feedline is long because I have to take a circuitous
route to my shack, passing through an exterior wall and an interior
Frankly, I wasn't expecting much from the antenna. I grew up with a
tower, tribander, and slopers for the low bands. I considered anything
as low as my doublet to be a cloud burner.
Last night I fired up my new rig (FT-1000D) on 40/80 and after spending
about an hour reading the manual and figuring out what all the knobs and
buttons do, I looked for DX. I worked the following over a period of
about 3 hours:
LU2 (80m SSB)
JA (2 on 80m CW, 1 on 40m CW)
RA0 (2, 1 on 80m SSB, 1 on 80m CW)
DS5 (80m SSB)
Certainly nothing ***, but I was pleasantly pleased that my low
doublet could get out at all! The signal reports I was getting were
either equal to other west coast stations or 1 S-unit lower. One
station actually said I was "loud". I almost fell out of my chair on
that one! I suspect many of the US guys (especially 80m SSB) were
running amplifiers. My FT-1000D was putting out 150W.
Today I'l see how well it works on 10m/15m/20m if the bands open up.
I've already verified that my tuner can load it on all bands except
Anyway, I don't know how well my configuration would compare to a G5RV.
It seems to me that if you have an antenna tuner and the space, why not
put up the extra length to go to 135' (full 1/2 wave on 80m)? I can't
wait to get mine up 10 feet higher to its final configuration of a
whopping 25' above the snow!!
I have both antennas up right now. On 80 meters I think the 135 does a little
better. On all the other bands the G5RV USUALLY does about 1 S unit better and
sometimes wins on 80. I'm going to take down my 135 I think and just go with
The G5RV is at 66 feet because the feedpoint is at the end of the 34 foot
vertical piece of 450 ohm ladder line. 66 + 34 puts the 51 foot elements at
100 feet just like the 135 foot dipole.
73 de Tom, K4NR
>I looked at the web page and yes he did a very nice job. But, notice that
>modeled the 135 at 100 feet and the G5RV at only 66 feet. Most people are
>lucky if they can get their wire up 50 feet. I wonder how the 135 would
>if lowered to the same height he modeled the G5RV at. I'll bet the G5RV
>becomes the clear winner.
The choice of 100' was more by accident, as that was the length of
ladder line that I bought. I figured that if I had trouble matching on
any band, I would experiment with adding/subtracting length until a
better match was achieved.
Today I spent more time listening rather than transmitting, trying to
figure out how the dual receiver feature in the FT-1000D works. I did
give P49M (Aruba) a call on 12m SSB and he came right back with a 57
report. A W7 received the same report, so I'm still pleasantly
surprised with the doublet's performance. Lots of JA's booming in on
15m but I didn't give any calls (I have 2 shoeboxes full of JA QSL's
from past contests).
I am using an MFJ-962B tuner which I picked up several years ago. It is
rated at 1.5 kW. Eventually I will get around to hooking up my TL-922
and will see if the tuner can really handle the power.
I had planned to build a 9:1 balun, put it outside the wall, and let the
FT-1000D built-in tuner handle the antenna (via coax from the balun),
but I read on W6RCA's page that he had made that mistake in the past
with a G5RV. I can't blame Cecil for trying, it sure seemed like a good
idea to me! (see http://www.geocities.com/CapeCanaveral/8476/wron
FYI, these are the pages I reviewed prior to selecting the doublet:
FYI2, I used 22 gauge insulated wire for mine. I wanted the antenna to
be as invisible as possible, and the green insulation blends in nicely
with the forest in the background. 22 gauge was about as small as I
thought I could go and still survive the regular blizzards.
Electrically, I believe the only difference in using small wire vs. the
more typical 12/14 AWG is that you will get higher Q/smaller bandwidth.
But since I am tuning the antenna anyway, I don't care. I can get 1.1:1
VSWR on all parts of all bands and the tuner settings seem repeatable.