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Streaky
Member
Username: Streaky

Post Number: 82
Registered: 3-2006
Posted on Tuesday, February 27, 2007 - 9:10 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Could swr be raised by having radials that are to close to 90 degrees?
Streaky
CEF #805
CVC #98
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2428
Registered: 9-2004


Posted on Wednesday, February 28, 2007 - 12:48 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

that depends on the type of antenna it is.

if we are talking about a 1/4 wave antenna, then yes, most definitely the radials should be at 45* and not 90*.

if we are talking about a 1/2 wave antenna such as an antron99; the radials wont have as much of an effect on feedpoint resistance.

i have heard of people running the maco v5/8 ground plane kit on their antrons years ago, and i dont remember hearing of any SWR issues.

again, this totally depends on the design of the antenna.
so which one are we talking about?
matt
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Streaky
Member
Username: Streaky

Post Number: 83
Registered: 3-2006
Posted on Wednesday, February 28, 2007 - 4:23 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

antenna is the Imax 2000
Streaky
CEF #805
CVC #98
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2432
Registered: 9-2004


Posted on Thursday, March 01, 2007 - 12:25 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i have absolutely no idea on that antenna, but my guess is that it wont raise the SWR by much, if at all, but it will change the take-off angle in a negative way.

if i remember correctly, the optimum angle for that antenna ground plane kit is 35*.
the kit must be slightly bent to acheive this.

i have not done it, and dont own one of these antennas, but there are numerous threads on here about this, from those who have, and liked it.

check out tech833's article "imax2000 exposed".
very informative.
good luck,
maybe 833 will pop in here and provide the difinitive answer.
matt

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