18-DEC-2008
5/8-Wave Groundplane
This is a sketch of the final design. It and the following 6 pics were placed in here first so you can avoid the history of the testbed if desired (it can be a bit dry to some).
The rest of those pics were left for the most part so folks could see how various building methods and materials were incorporated into it, and for inspiration.
When i got finished tweaking this, I put it up! It was mounted on the ground durring the study, and performed extremely well with the mast ground directly to the ground field in my back yard, and the radials touching the ground, 4 feet from the base.
18-DEC-2008
Final Design
SWR is under 2:1 from 26.960MHz to 29.890MHz. Reports are excellent. Sure, its ugly. But it is paid for. Pay no attention to the wire going-off horizontally from the base. It's just one end of my G5RV dipole, or sometimes called a "dummy load" (sorry -- just an old ham joke, hi hi). Actually, I've made hundereds of DX contacts on that piece of wire!
PARTS SOURCES AND PRICES OF MATERIALS USED:
Large(1inch to 3inch size heatshrink Tubing available only one place that I know of, that being
"Parts Express".The cost depends upon the diameters,with the entire cost for what I used to weatherproof my antenna at around $15.00. Add a couple sticks of hot glue for sealing. 4FT of 1"x1/8" aluminum bar stock from lowes($15.00)
"MIGHTY PUTTY" Cost $10.00 for three sticks....One telescoping "pool pole from
BJ'S Wholesale Club , (sort of a Costco,or wholesale wally word) Price $16.00
I used #12 solid copper, but #14 stranded works just as well, except for the top hat. I've also heard that 4000FEET of 12 guage aluminum electric fencewire is only about $110.00 from
Tractor Supply stores.If this is true, my next project may be a Rhombic for 160METERS :)Another great online source for wire is
"The Wire MAN"out of SC. He has all KINDS of neat toys!!
AS-BUILT PARTS LIST:
4-10 foot fiberglass telescoping fishing poles
1-Copper ground wire clamp
1 box:#8-5/8" self-tapping screws
1 pkg:JB Weld
2 EA: 2" hose clamps
1 pack :Hot glue sticks
1 EA: acid brush
1 EA: SO-239 connector
1 pack: (8 ea) 1/2 conduit clips
1 12" piece of 1.25"sced 40 PVC pipe for insulator section.
1 12" piece of 2" PVC electrical conduit (fits nicely outside of the 1.25"PVC for super strength).
44Feet: #14,16, or 18 copper wire for ground radials(make sure at least2 feet is solid for coil).
21.2 Feet: tubing, preferably aluminum, but whatcha got? Can be telescoping (one section inside another).
Clamping hardware
13-DEC-2008
The Coil
Formed by coiling 23 turns of #12 solid copper wire around a 1/2"PVC water pipe with 1.5" straight ends for attachment. Length as designed is 13". The insulated gamma support, made from a plastic paint stir stick, can also be seen. The coil is attached at the bottom to an SO-239 coax connector. It is mounted on a piece of scrap alluminum bent into a 90, and atached to the base witrh self-tapping screws... But use whatcha got.
The idea is to "talk cheap" and learn something new -- otherwise, you might as well purchase a MaCo V-58.
13-DEC-2008
Top of gamma rod
This shows the shorting strap made from sheet alluminum which connects the top of the gamma rod to the radiator. The white nylon cap on top of it is NOT needed. I just thought it might keep rain-induced SWR down by keeping water out of the gamma tube.
13-DEC-2008
bottom of gamma rod and coil
The adjustment rod is not yet installed in the bottom of gamma tube this pic.Also note that there is no capacitive insulation in between the top and bottom insert of the gamma rod. It tunes the same tho.
I just wanted to show the bottom attachment of the gamma rod to the mast. Note that it is plastic. This connection is just to attach support the base of of the gamma to the mast and MUST be made of some sort of stiff, non-conctive material... The more UV-proof , the better.
13-DEC-2008
Insulator (closer view)
A re-shaped 1/2" conduit clip was used to attach the insulating support it to the gamma rod.
13-DEC-2008
Complete Matching Network (Except for the adjusting rod)
The missing rod (Labled "E" insert on the sketch) fits inside the gamma tube at it's base.
It can be seen in later pictures.
20-JUL-2008
Base of Radiator
The radiator bottom section was scrounged from a PDL-2 beam that didn't
survive Hurricane Charley in '04. The black do-dad is the PDL's old
gamma ring insulator..... It did not want to be removed.
The white piece is 1.5" sched 40 PVC water pipe. This insulates the base of the final assembly.
Note that any aluminum tubing can be used for this vertical radiator tho. I have found adequate tubing in the form of a pool pole. I bought one for 15buks just to experiment with. But it will be used in another behemouth antenna I am contemplating for 20/40/80 meters.
I'm just mentioning it here because it can take the place of the PDL tubing that I used here.
20-JUL-2008
1.5" Sced #40 PVC
The radiator's base is inserted 6" into the PVC and secured with self tapping screws.
The ground wire clamp (the copper fitting protruding from the middle of the PVC), was purchased in the elctrical department of Home Depot to secure the radiator end of the coil, and is attached to the base of the aluminum radiator on the inside.
26-JUL- 2008
Crappie ground radials
Who has time for crappie fishin when there are antenna "errector sets" to play with? :) These are "keepers"! Four of these 10'3" crappie poles with #12 solid copper wire shoved up the center, make up the ground radial system for my perminent antenna. They were less than five buks each at
ALLWATERS FISHING SUPPLY.
Cheaper still, would be to illiminatethe poles, and just use wire. The wire ends could be attached to nylon guy ropes and serve double-duty... I don't have the room needed for the extra guy anchors, so we have self-supporting ones in the form of fishin poles. BTW, they can still double as guy points by using the eyelets that are on the ends of the poles (for tying fishing line to).
06-AUG- 2008
Telescopic crappie pole (as yet, un-messed with)
This is really the way to go. I've also seen hams use the longer ones as supports -- and even verticals. After all, add wire up the middle, a coil at the base,a cheapo disc capacitor, and you'll have a homemade Antron A-99 ground plane!
I would advise against the a-99 route, however, as i almost lost a step child to the effects of lightning vaporizing my a-99 (see "lightning sculpture" in another gallery of my web host site)....
HOWEVER -- since this homebrew 10meter vertical is a "shunt-matched" antenna design (the whole structure is at ground potential,with no capacitors and such), lightning should treat these radials just like metal ones.
06-AUG- 2008
Cut off the butt
A cutoff disc werks great for this, as does a dremmel drill with a cutoff wheel.
