| Author |
Message |
    
Keithinatlanta
| | Posted on Wednesday, December 17, 2003 - 7:51 pm: | 
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Tell me if this will work for a temporary base station antenna. I have a 96" Francis fiberglass whip( I think that length, but for sure not 102" ) that I would like to mount on a push up pole that is forty feet. Mount the antenna on one of those upside down L shape brackets like you would put on the side of a truck. Mount the bracket to the top of pole and up she goes. Will this work as a groundplane antenna or not? How would I ground it if this set up will work? I have 75 feet of coax to use that I had bought from Copper. Thanks for the advice.
Keith in Atlanta |
Damyankee
| | Posted on Wednesday, December 17, 2003 - 8:46 pm: |
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Keith,
I'm no antenna guru but I see no reason why it won't work. Maybe not great, you may have to play around to get your SWR in-line, BUT you did say temporary. If your mast is well grounded and you use U-bolts to attach the bracket no "extra" ground should be required. Most auto type antennas like coax lengths of 18'...
I'd try it just to see. As long as your SWR is OK you won't hurt anything.
My $.02 - Ron |
Crafter
| | Posted on Wednesday, December 17, 2003 - 9:25 pm: |
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Well yes it will you might try and add several wires to get it to radiate if your talking local it should work as well as if you were mobile. |
Keithinatlanta
| | Posted on Wednesday, December 17, 2003 - 10:28 pm: |
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Well , that is the game plan until I can get this new super scanner up in the air. Maybe during the holidays I can make the simple one work to start. Got to have time to put the other one together first. I was hoping it might work so I could get out on the net on Sundays. I have just not had any luck trying to talk to everyone on the CEF Sunday net! I was kinda hoping that might be a short term solution. Thanks.
keith in Atlanta |
Mr_Rf
| | Posted on Wednesday, December 17, 2003 - 10:44 pm: |
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Keith, you have just discovered the basics of a 1/4 wavelength ground plane antenna. As Crafter pointed out you need ground radials.
Add three or more radials, grounded to the mast pipe just uunder the antenna, and coming off at about a 45 degree angle. If it's a push-up pole then use rope to guy the top ring, and hook up several #12 copper wires to the clamp on the L-bracket. Then tie-strap or tape them to the ropes for ground radials.
Good Luck. |
Crafter
| | Posted on Thursday, December 18, 2003 - 11:58 am: |
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Similiar to what hustler does with the 5 btv.
DX Engineering has a cool addition to the hustler antenna.
On the radials make sure to use at least four and try to make them opposite of each other. |
Znut
| | Posted on Thursday, December 18, 2003 - 10:16 am: |
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I once used a 4' firestick mounted to a piece of aluminum with 3 peices of speaker wire, 108 inches long taped to PVC pipes screwed to the plate and mounted on a chain link fence. It worked great, considering the height. It sure would work some DX, even better than folks 5 miles away.
That Francis antenna should really work great and have better SWR than a straight 1/4 wave. A steel whip may be a little more efficient, though. |
Crafter
| | Posted on Thursday, December 18, 2003 - 6:39 pm: |
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Use 4 wires 4 foot 5 inches each, bet it works like a charm connect them to the mount. |
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