G5RV vs. 135' dipole RESULTS

G5RV vs. 135' dipole RESULTS

Post by K7j » Sat, 13 Feb 1999 04:00:00

Tom, K4NR, was a true saint and modelled both of these antennas for me. You
must see his homepage...he did a superb job and a great service for our
community. Check it out: http:home.earthlink.net/~k4nr/antenna/135-G5RV.htm
Thanks to Tom and all who responded. Best 73, John, K7JY.
 
 
 

G5RV vs. 135' dipole RESULTS

Post by Eric Ju » Sat, 13 Feb 1999 04:00:00


John,

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
wall.

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
160m.

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!!

--
Regards,

Eric June
KU6J

 
 
 

G5RV vs. 135' dipole RESULTS

Post by W6RCecil » Sat, 13 Feb 1999 04:00:00


> 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
> wall.

100ft of feedline is close to optimum for that antenna. Check out my
All-HF-band-no tuner 130 ft dipole on my web page. Closely notice
where the current maximum points (current loops) are. If you shorten
the feedline, you are likely to introduce problems.
--
73, Cecil, W6RCA   http://www.bigfoot.com/~w6rca
 
 
 

G5RV vs. 135' dipole RESULTS

Post by Karl Klingma » Sat, 13 Feb 1999 04:00:00


> Tom, K4NR, was a true saint and modelled both of these antennas for me. You
> must see his homepage...he did a superb job and a great service for our
> community. Check it out: http:home.earthlink.net/~k4nr/antenna/135-G5RV.htm
> Thanks to Tom and all who responded. Best 73, John, K7JY.

John,

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.

Karl AF4IX

 
 
 

G5RV vs. 135' dipole RESULTS

Post by Karl Klingma » Sat, 13 Feb 1999 04:00:00


> Tom, K4NR, was a true saint and modelled both of these antennas for me. You
> must see his homepage...he did a superb job and a great service for our
> community. Check it out: http:home.earthlink.net/~k4nr/antenna/135-G5RV.htm
> Thanks to Tom and all who responded. Best 73, John, K7JY.

I looked at the web page and yes he did a very nice job.  But, notice that he
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 look
if lowered to the same height he modeled the G5RV at.  I'll bet the G5RV
becomes the clear winner.

73's
Karl AF4IX

 
 
 

G5RV vs. 135' dipole RESULTS

Post by Tom Branc » Sat, 13 Feb 1999 04:00:00

Karl,

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
he
>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
look
>if lowered to the same height he modeled the G5RV at.  I'll bet the G5RV
>becomes the clear winner.

 
 
 

G5RV vs. 135' dipole RESULTS

Post by K7j » Sun, 14 Feb 1999 04:00:00

Eric, Tnx for the reply....much appreciated. How did your antenna perform
during your tests on the higher bands today? Also, just out of curiousity,
which tuner are you using? Best 73, John, K7JY.
 
 
 

G5RV vs. 135' dipole RESULTS

Post by Eric Ju » Sun, 14 Feb 1999 04:00:00

Cecil,


> 100ft of feedline is close to optimum for that antenna. Check out my
> All-HF-band-no tuner 130 ft dipole on my web page. Closely notice
> where the current maximum points (current loops) are. If you shorten
> the feedline, you are likely to introduce problems.

Thanks, I had found your site and reviewed your information carefully
before putting up my antenna.  As I mentioned to John, I had
independently come up with the "brilliant" idea to build a 9:1 balun and
let my FT-1000D directly tune the antenna.  Then I read your
http://www.geocities.com/CapeCanaveral/8476/wrong.htm article and
decided that it would be better to bring my ladder line all the way to
the shack!  :-)

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.

--
Regards,

Eric June
KU6J

 
 
 

G5RV vs. 135' dipole RESULTS

Post by Eric Ju » Sun, 14 Feb 1999 04:00:00

John,

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
g.htm).

FYI, these are the pages I reviewed prior to selecting the doublet:

http://www.geocities.com/CapeCanaveral/8476/
http://www.contesting.com/km9p/openwire.html
http://funnelweb.utcc.utk.edu/~cebik/radio.html

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.

Good luck!

--
Regards,

Eric June
KU6J