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Red_devil
Junior Member
Username: Red_devil
Post Number: 27
Registered: 10-2004
| | Posted on Monday, January 24, 2005 - 7:19 pm: | 
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This is my basic design for a CB ground plane antenna. Any suggestions will be welcomed and appreciated. (Photos of Plan below)
The Plan:
Start with a 4x4 piece of wood cut form with a 5/8’ hole 3’ deep in the center to hold the vertical radiator. To be glued with epoxy upon final assembly.
Drill a diagonal hole, lined with a waterproof conduit, to extend below the ground plane radials and use epoxy to hold into place.
Cut horizontal notches into the block to provide additional support to ground plane radials to be screwed into place upon final assembly.
Cut recess into the side of the wood for the mast pole.
Seal the wooden block with waterproof compound (i.e. sealant, paint).
Cut five lengths of 5/8” aluminum tubing to center of band 103.29” (between 103 5/16 and 103 9/32).
Assemble ground plane radials by drilling holes and using wood screws to attach. Place waterproof end caps onto all radials. Place copper wires between ground plane radials and solder or screw into place.
Route RG8 coax through the drilled channel leaving the shield exposed below the hole.
Drill hole in radiator element for coax lead attachment later. Place waterproof end cap onto radiator. Insert the radiator element into the top hole and epoxy into place.
Once epoxy is cured, attach center lead of coax to the radiator and shield to one or all ground plane radials.
Seal all connections and exposed wire with silicone sealant.
Design Questions:
Should the wood be extended vertically so the radiator element be kept above the ground plane radials?
Is 5/8” diameter aluminum tubing too thick for radiator or ground plane elements?
Will three inches of wood be enough to hold the radiator?
Is it best to route the coax shield to each ground plane radial or is one adequate?
Thank You again for any technical assistance
CEF 447
Red Devil - 392
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Tech833
Moderator
Username: Tech833
Post Number: 965
Registered: 8-2002
| | Posted on Monday, January 24, 2005 - 10:36 pm: |
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Looks like a standard ground plane antenna. I will address your questions-
"Should the wood be extended vertically so the radiator element be kept above the ground plane radials?"
It does not really matter.
"Is 5/8” diameter aluminum tubing too thick for radiator or ground plane elements? "
Not at all. The larger the tubing, the better the bandwidth and power handling capability.
"Will three inches of wood be enough to hold the radiator? "
If it doesn't get too windy, then yes. Wood is not nearly as rigid as fiberglass.
"Is it best to route the coax shield to each ground plane radial or is one adequate?"
Each one would be best. The lower the impedance the better.
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Red_devil
Junior Member
Username: Red_devil
Post Number: 27
Registered: 10-2004
| | Posted on Monday, January 24, 2005 - 11:32 pm: |
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Lon,
As usual, you are the MAN with all of the answers. Thank you for taking the time to look at my project. I wanted to get an expert opinion before my limited experience and I began a project that would be a money pit.
Again, I appreciate all of the help of the CEF membership and their shared experiences and knowledge.
Hope to hear you Sunday on 13 / 27.115 (LSB)
CEF 447
Red Devil - 392
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Tech808
Moderator
Username: Tech808
Post Number: 4624
Registered: 8-2002
| | Posted on Monday, January 24, 2005 - 11:45 pm: |
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Red_devil,
Thanks but Iam not the one who answered your Post.
You need to THANK Tech833 / Paul as he is who replied / answered your questiion. 
Lon
Tech808
CEF808
N9OSN |
Red_devil
Junior Member
Username: Red_devil
Post Number: 28
Registered: 10-2004
| | Posted on Tuesday, January 25, 2005 - 9:06 am: |
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WELL,
I guess I owe PAUL the flowers.
Boy, when 833 looks like 808 I guess it is time to put the reading glasses back on. I don't know what to do when I imagine seeing things like the POW-MIA flag and the name LON at the bottom of a posting :-).
Thanks again Paul for the help and Lon for keeping us all striaght.
CEF 447
Red Devil - 392 |
