| Author |
Message |
    
Bluebird
Junior Member
Username: Bluebird
Post Number: 30
Registered: 2-2004
| | Posted on Friday, January 12, 2007 - 10:14 pm: | 
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i have a vertigal gain antenna 22ft 6" 5/8 wave,with a tuning ring.
it is a homemade ant,,,the plans told me that the radials had to be 102",,but on other plans the radials have to be the same lenth as the antenna. what is the correct lenth to have the radials? thanks
MITCHELL
BLUEBIRD
CEF #398
CVC #113
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Tech833
Moderator
Username: Tech833
Post Number: 1586
Registered: 8-2002
| | Posted on Saturday, January 13, 2007 - 12:54 am: |
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1/4 wave, or about 108 inches. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1453
Registered: 6-2004
| | Posted on Saturday, January 13, 2007 - 7:53 pm: |
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Some modeling programs show a lower takeoff angle when 5/8 wavelength radials are used, but they have to be at least 135 degrees from the vertical radiator, and 160 degrees is apparently the optimum angle.
Aack! - Bill the cat
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Bluebird
Junior Member
Username: Bluebird
Post Number: 31
Registered: 2-2004
| | Posted on Sunday, January 14, 2007 - 10:00 am: |
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thanks alot guys,,,i am going to try 1/4 and 5/8
wavelengths and see what works best
MITCHELL
BLUEBIRD
CEF #398
CVC #113
|
Tech833
Moderator
Username: Tech833
Post Number: 1589
Registered: 8-2002
| | Posted on Sunday, January 14, 2007 - 11:06 am: |
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HP- 5/8 wave radials? You do realize that if precicely tuned, would set up some odd current nodes that would distort the capacitive conduction along the Earth, right? |
Speedinevada
New member
Username: Speedinevada
Post Number: 2
Registered: 12-2006
| | Posted on Monday, January 22, 2007 - 3:31 pm: |
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just purchased and installed imax2000, setup at first alone, then with ground plane kit. alone able to get swr down to 1:1, with swr is almost 2:1. another user in my area told me TVI was a problem for him with ground radials, removed them and it helped. noticed when cold at night swr rises, sun comes out and it lowers again. is this normal? my old starduster wasnt effected by temperature, always 1:1 swr, even with numerous hose clamp / brass stud repairs. for now leaving ground radials off... |
Slugo4449
Intermediate Member
Username: Slugo4449
Post Number: 150
Registered: 7-2004
| | Posted on Monday, January 22, 2007 - 8:26 pm: |
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Usually a change in SWR, because of temp, is a moisture problem.
Hows the connectors and connections? Did you water proof all of your pl-259's?
If you get TVI, try some decoupling loops at the base of the antenna with the coaxial cable. Just make about 7-9 loops in the coax.
Marty |
