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Tech808
Moderator
Username: Tech808

Post Number: 17373
Registered: 8-2002


Posted on Friday, January 22, 2010 - 7:24 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

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Lon~Tech808
N9CEF
CEF#808~CVC#002

Radio Enthusiast!

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Tomcatinva
Intermediate Member
Username: Tomcatinva

Post Number: 128
Registered: 11-2003


Posted on Saturday, December 19, 2009 - 11:02 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Just a quick question... Has anyone tried one of these "Slinkey Dipole" antennas on 11 meter SSB? and if so what were your findings? Did you like it and how did you mount it, inside or outside? I am thinking about getting one and mounting it in my attic. Right now I have a 102" whip mounted on a home made ground plane kit (an old radio shack scanner antenna ground plane). Works ok but I was thinking that a Dipole Antenna would give me better distance... the antenna would be facing east and west with the ends (left and right) being north and south. Hope that helps discribe my set up... Thanks and hope everyone has been doing well...
TomCat in VA
CEF217
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Tech237
Moderator
Username: Tech237

Post Number: 1271
Registered: 4-2004


Posted on Saturday, December 19, 2009 - 11:50 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Tom,
I have not tried one on 11m but did use a homemade one (1982-3) on the RAAF Base on 80-10 with great results. I did use a tuner with it to help, but should work resonably well n 11m.

Ours was vertical,as the shack was 110ft above ground in an old Air Traffic Control Tower, but get it about 20ft or so and should work.
Tech237
N7AUS

Chipmonks roasting on an open fire
Hot sauce dripping from their toes.
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Tomcatinva
Intermediate Member
Username: Tomcatinva

Post Number: 129
Registered: 11-2003


Posted on Monday, December 21, 2009 - 12:04 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thanks for the response... I am thinking about getting one and setting it up in my attic. But with every thing in my thought process that is subject to change...
TomCat in VA
CEF217
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Joey_migs
Member
Username: Joey_migs

Post Number: 82
Registered: 9-2009
Posted on Friday, January 22, 2010 - 1:57 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

First off, the feedpoint of dipole 70 - 72 ohms
For perfect match with is the RG-59, or any other 72 ohm coax with a low db loss/100 ft.
To prevent current down the coax sheild, i am using a 6 turn RF choke. the RG-59 will meet a 75 to 50 ohm balun, SWR meter then the radio.

Am I missing any thing. If I reduce the height of the dipole, the feed-point impedance will go down, to an idea 52 ohms, and I can then use RG-8 or RG-58, with a 4~5 turn RF choke below feed-point and eliminate the need for a Balun.
I am On the right track

Joe
AKA AC2CH
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 4782
Registered: 7-2004


Posted on Friday, January 22, 2010 - 7:14 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

a slinky antenna is what any antenna with a coil is.....a less-then-maximum-efficiency-antenna, because it is effectively being shortened. you also MAY run into resonance & impedance issues with a slinky antenna, the same as a coiled mobile antenna. especially on windy days. the spacing between the coils affects impedance. and whereas a mobile antenna with a 'firm', and 'moldable' coil can be evenly spaced, the slinky's coil spacing will vary, especially in the wind.
does it mean that it won't work? no. & won't work good? not necessarily. an 'un-coiled' dipole will work better.

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