I once own a butternut antenna
and sold it. What a bad mistake that
was!
The butternut antenna
I once own was a 5 band vertical and work really good
considering I did not have any radials down, and did not have the
space to put any down. Since I was lucky enough to have
someone
give me lots of aluminum stock, I decide to try my hand at building a
mock up of a 80/40 meter version of a butternut antenna. So the
search for information began. The internet is a great tool for
information. I found website with manuals of different version of the
butternut antenna. But what really grasp my attention was when I came
across
EI7BA
website and read how he had re-work a butternut antenna he had. I
began taking inventory to see what needed. All I was missing
were some hose clamps and capacitors.
Constructing The Vertical:
The total height
of this antenna is 33 FT. So lets get started.
Step 1:
All
of my 1" OD
tubing is
11 FT in length. Starting with the bottom section of the antenna, a
piece of 11 foot aluminum tubing was cut down to 6'. This is different
from the original version. Next is the first upper section which is
also a 1" OD tubing and kept at its original 11' height. When building
yours, you may need to make some adjustment to achieve 11 feet. When
purchasing aluminum tubing by mail. There usually only ship in 8'
section. In that case you'll be able to get aluminum stock that will
inter-lock with each other. I had a little bit of a problem with mine.
I'll explain more later.
Step 2:
Now
you'll need to join the 6' section and the first upper 11' section
together and at the same time not have the two section make
electrical contact with each other. How I achieve this was I used what
I had on hand.
I used a peace of 1/2 PVC tubing cut 8" inch long. Inserting 4" of
the PVC tubing into the 6' section and 4" into the
11' section leaving
a 1 inch spacing between the to. Then
drilling a hole on each end of the tubing and making sure they line up
with each other. I then inserted a 1 1/2 brass
screw
with nuts and washers to lock it in place. Now to make it a bit stronger.
I cut a peace of 1" ID PVC tubing 10" long. Using a hawk saw
I split
the tubing down the middle. Only cutting one side of the PVC tubing and taking out
about 1/4 inch of it. The
reason for splitting the 1" ID PVC tubing was
so that I could slip this over 1" OD aluminum tubing and around
the screws
that I put in place to hold the 1/2" PVC tubing that was inserted
in the inside of the two section. Here's a picture of what I'm talking
about Fig 1 (Click here). You should have a total height of about 18 feet which
includes the 1 inch spacing between the lower 6 foot section and the
upper 11 foot section. From this point on if you have tubing that will
inter-lock with each other then continue on installing the tubing to
get your full length of 33 feet and making sure to use hose clamps to
fasten each section together. I did not have the correct size tubing
to fit inside the 1" OD tubing I had. So to make this work this is
what I did to make up the 15 feet I would have been short. This
picture will show and tell you what I did (CLICK HERE) .
Step 3:
The Coils:
Now for the 80/40 meter coils.
The coils were make from 1/4
aluminum tubing that I had, I sure you could use copper and get away with it if
that's all you have on had. The coils have a ID of 4" inches. I used a 1 quart
paint can that measure about 4 1/4 inch or so round, Close winding the
1/4 tubing around the paint can with 18 turns made up the 80 meter
coil.
Doing the same process 10 turns of the 1/4 inch round tubing made up the 40 meter coil.
You will had to bend the
ends a little when time to fasten the coils to the tubing and using hose clamps
to fasten them in place. Here's a picture of the coil (Click
Here).
Step 4:
The Capacitor Plate:
Making
the capacitor plate. Here again I used what ever scrapes
of material I had laying around. I had a peace of 1/2" wide heavy
aluminum about 3' long
which I bent and molded into shape using a vise. This was used to hold
the 200pf 7.5 kv door knob capacitor and the 68pf 7.5 kv capacitor in
place. At the time of construction mid summer of 2007 I only had the
68pf capacitor which you'll see from the first picture. As of today
December 13, 2008 I'm updating this page and will be making
adjustments to the antenna soon. I have purchase two 100pf 5 kv
capacitors. And my capacitor bracket will be modified. Yes its a bit
cold outside now. Click here to view picture and
more information.
Step 5:
Antenna Mounting Bracket:
Ground mounting
the antenna.
I had a 5' section of fence piping about 1
1/2" OD. I drove two feet of this into the ground.
From a peace of scrap plywood I then cut a 12x12 section out. And then drill
two sets of holes in order to mount the plywood to the fence pipe with u-bolts.
And then another set of holes were drill to hold the bottom 6' section
of the antenna to the plywood. The plywood was weather coated with
about 6 coats of polyurethane in order to protect it from the weather.
When ever I need to lower the
antenna all I have to do is take out the bolt that holding the antenna
in place and it can be lower to the ground. Here's a picture of
the bracket...
Now lets see how this baby holds up this coming weather 2007- 2008
Note:
I added 9 ground radials. Plus the
ground system is tied into a 40 foot chain
link fence. Don't know if the fence is helping. And being that I have
a small city lot that's the best I can do as far as a ground radial
system goes.
Tuning The Antenna:
Tuning this antenna was a big pain in
the (Butt). Running in and out of the shack to the rig to the
antenna. After an hour of this I stop. I then broke down and purchase a
MFJ-259B antenna analyzer. Yes the analyzer was a little costly for
one project. But I had plans on building some other antenna. So it
will come in handy.
Still
working on the tuning of this antenna. Will report my finings as I go.
I'm not happy with my swr and having lots of rfi problems.
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Noisy Band:
80/40 meters are very noisy bands to work at my location. My noise level most of the
time is S7 - 9 until
very late in the night it my drop down to a S5. I have a neighbor who
a ham and lives at the other end of the block from me. He works mostly
75 meters using a Carolina Windom antenna. He tell me that he does not
have the same noise level as I. Now figure out why ?
Up Dated December 13, 2008 noisy band conduction.
Well after
playing with the antenna on and off. I have figure out part of my
noise problem, and what I can do to solve and or correct it if at all.
I must mention that this noise problem only affects 40, 80 and 160
meter bands. I do not have an antenna for 160 but do listen from time
to time.
1.) Listing on the vertical is still very noisy. So what I've tried
doing is using my 20 meter loop antenna as a receiving antenna for 75
meters. What I've come to fine out is that the 75 meter band is much
quieter to listen to using the loop. The noise level on the vertical
is a S-7 to S-9. On the loop antenna the noise level is anywhere from
a S-0 to S-3 -4 most of the time unless band condition are really bad.
My loop antenna is just about 25 feet off the ground. So I will do one
of two things. Either build another loop just for receiving. Or use
this loop antenna after I build my 5 band Hex Beam. And then build a
switching relay system. So that when I transmit the relay switches
over the vertical antenna and when not transmit it switches back to
the loop.
2.) The second thing I've come to fine out is that my computers are
causing some RFI problems into my receiver. Here's just a few
things I've done so far that has help. Using snap on ferrite core I
place two on my hard drive cable. Now when ever my hard drive is
running I no longer hear it in my receiver. But I still have so
problem that I'm working on.
3.) Cordless devices. I have a cordless mouse that is generating noise
into my receiver. I warp the cable around two snap on ferrite core and
that took care of that.
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First contact on 40 meters was with WT8E and received a signal report
of 55. The same goes
for 80 meters. A 55 report with a Delaware station and a up state New York.
Credit For This Project goes to EI7BA.
For more technical information has to how it all works
visit
John's website.
Thanks much John for the nice website and emailing me 73's. |