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Message |
    
Tech237
Moderator
Username: Tech237
Post Number: 1048
Registered: 4-2004
| | Posted on Friday, August 15, 2008 - 3:54 pm: | 
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OK, Old age must be getting to me. Sometime in the last few days I approved a post that mentioned using a colinear array, adn of course I cannot now find the thread to add the following information.
A vertical colinear for 28.5MHz ( I thinkj the firstpost mentioned 11m)that has three sections is close to 50ft (49.2ft) and only has a gain fo around 3.3db. So to be honest a vertical colinear is not teh best antenna for those frequencies..
Simon
Tech237
N7AUS
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Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 415
Registered: 9-2004
| | Posted on Saturday, August 16, 2008 - 7:30 am: |
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It may have been me that posted the reference to colinear antenna but ,I was refering to the use of colinear antennas on vhf and uhf.
Bob VE1CZ/CEF451
Robert L. Spicer The days of radio are just beginning!
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Bruce
Senior Member
Username: Bruce
Post Number: 4789
Registered: 9-2003
| | Posted on Saturday, August 16, 2008 - 9:29 am: |
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They make a coliner for 52 mhz (2) 5/8 waves stacked its 24 foot tall ......
On 6 since 66
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Tech237
Moderator
Username: Tech237
Post Number: 1050
Registered: 4-2004
| | Posted on Monday, August 18, 2008 - 6:41 pm: |
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Bob, no some one did make a reference to using one on 11m..
Simon
Tech237
N7AUS
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Tech833
Moderator
Username: Tech833
Post Number: 1688
Registered: 8-2002
| | Posted on Tuesday, August 19, 2008 - 11:36 am: |
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Hustler used to advertise their 5/8 wave ground plane as a colinear. Complete misuse of the word.
Actually, anyone can build a colinear array with two similar antennas. Just mount one over the other and feed with a co-phasing harness. The most gain would come from full-wave spacing, but half-wave spacing would work almost as well. |
Tech237
Moderator
Username: Tech237
Post Number: 1055
Registered: 4-2004
| | Posted on Tuesday, August 19, 2008 - 10:57 pm: |
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Hey welcome back stranger. You've been missed
Simon
Tech237
N7AUS
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Press_man
Junior Member
Username: Press_man
Post Number: 16
Registered: 5-2008
| | Posted on Tuesday, November 11, 2008 - 7:14 pm: |
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Hi guys!
Who's the resident antenna tech? I read a rather intense artical on empedance matching, filtering and counterpoise.
When the station was last up I used a Tee and 9' of shorted coax inside the shack (as per Hints and Kinks)laid out on the floor for complete TVI trapping. It created some what of a counterpoise as well.
The article I read said to place the Tee and 9' of shorted coax at the antenna. By the math the C.P. was more effective at the antenna as well as offering better TVI trapping.
I'll be putting an Astro Plane back up for 10/11m (works on 12m too). If I put the Tee at the antennas SO239 I would need to mount the two coaxs on seperate standoffs which is no problem. Or by virtue of the antenna's design should the counterpoise be made below the hoop. Math says it won't hurt to be inside,but,it still makes me wonder about trapped emissions.
Hhhumm! Questions and posers.
Any ideas?
Wally/kc4zwm |
