Copper Talk » Ask The Tech » Antennas » Antenna Answer « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech237
Moderator
Username: Tech237

Post Number: 1048
Registered: 4-2004
Posted on Friday, August 15, 2008 - 3:54 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

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

Top of pagePrevious messageNext messageBottom of page Link to this message

Captian_radio
Intermediate Member
Username: Captian_radio

Post Number: 415
Registered: 9-2004
Posted on Saturday, August 16, 2008 - 7:30 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

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!
Top of pagePrevious messageNext messageBottom of page Link to this message

Bruce
Senior Member
Username: Bruce

Post Number: 4789
Registered: 9-2003


Posted on Saturday, August 16, 2008 - 9:29 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

They make a coliner for 52 mhz (2) 5/8 waves stacked its 24 foot tall ......
On 6 since 66
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech237
Moderator
Username: Tech237

Post Number: 1050
Registered: 4-2004
Posted on Monday, August 18, 2008 - 6:41 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Bob, no some one did make a reference to using one on 11m..
Simon
Tech237
N7AUS

Top of pagePrevious messageNext messageBottom of page Link to this message

Tech833
Moderator
Username: Tech833

Post Number: 1688
Registered: 8-2002
Posted on Tuesday, August 19, 2008 - 11:36 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

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.
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech237
Moderator
Username: Tech237

Post Number: 1055
Registered: 4-2004
Posted on Tuesday, August 19, 2008 - 10:57 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hey welcome back stranger. You've been missed
Simon
Tech237
N7AUS

Top of pagePrevious messageNext messageBottom of page Link to this message

Press_man
Junior Member
Username: Press_man

Post Number: 16
Registered: 5-2008
Posted on Tuesday, November 11, 2008 - 7:14 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

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

Add Your Message Here
Post:
Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: