Go Back   WorldwideDX Amateur Radio Forums > Amateur Radio Related > Amateur Radio Antennas


Amateur Callsign Lookup
Enter Callsign:

HELP WITH DIPOLES AND INVERTED V'S

Reply
 
LinkBack Thread Tools Display Modes
  #9  
Old 06-09-2009, 08:48 PM
Beetle's Avatar
Senior Member
iTrader: (0)
 
Join Date: Dec 2005
Location: Western Washington
Posts: 2,469
Beetle is on a distinguished road
Default


Quote:
Originally Posted by rfoverlord View Post
Tony,
how high up are the ends and are you running this as a flat top or inverted "v" also how is it oriented N-S or E-W? Iv'e tried a couple of different dipole configurations 102' and 133' and a fan dipole (it actually worked good 10-20) but that was getting to big to keep up in the wind. My best ant so far has been a homebrewed cobra ant. 73' per leg physically made with rad shack 3 conductor rotor control wire fed with a quarter wave length of 450 ohm twinlead from a DX engineering 1:1 balun plays real nice 10-160 of course 160 has always within 1800 miles but it works. 10-40 i don't even need a tuner.
A "quarter wave length" doesn't tell us much since this is a multiband antenna apparently. Quarter wave on which band?
__________________
If you're like everybody else,
you're about average.
73 de K7KBN
CWO4 USNR RET.

Reply With Quote
  #10  
Old 06-09-2009, 10:14 PM
TonyV225's Avatar
W9WDX Amateur Radio Club Member
iTrader: (8)
 
Join Date: Apr 2005
Location: Wisconsin
Posts: 5,720
TonyV225 is on a distinguished road
Default

Ok its sold as a multiband antenna I find myself mostly on 75-80 meters but I do skip around a bit from time to time. I am looking for ideas or advice on whats my best bet to run as an antenna double bazooka, flat topped dipole etc.

As far as my G5RV the apex is at maybe 35-40 foot the ends are about 6 foot or so off the ground I know they need to all go higher but before getting help here to get this done because I obviously am not in the health to be doing this myself I want to look at other possible options as far as a multiband basically what as far as a multiband is better than a G5RV and as far as my G5RV what height should I run this apex and ends if I were to leave this up?

Right now the apex would be poited west.
__________________
""""was not thinking of a cber sat with his makita screwdriver winding round the presets untill his meter said s9+60db from a guy on a handheld 15 miles away""""

Reply With Quote
  #11  
Old 06-10-2009, 07:35 AM
Beetle's Avatar
Senior Member
iTrader: (0)
 
Join Date: Dec 2005
Location: Western Washington
Posts: 2,469
Beetle is on a distinguished road
Default

Center fed doublet as long and as high as practical. Balanced feedline directly to the tuner. Build the antenna yourself and use a good commercial feedline and quality insulators. For multiband operation it doesn't get much simpler or more effective. Might need to experiment with feedline length for some bands; might not.

All antennas are compromises in some way, and this one is no exception.
__________________
If you're like everybody else,
you're about average.
73 de K7KBN
CWO4 USNR RET.

Reply With Quote
  #12  
Old 06-10-2009, 02:23 PM
Senior Member
iTrader: (0)
 
Join Date: Aug 2008
Posts: 543
HiDef is on a distinguished road
Default

You got some good answers and, well...

A lot depends on what you want to work.

If it's DX on 160 and 80 the antenna needs to be quite high to keep up with the Jonses. If you want to be regional and work your buddies a few states over 60 feet in the center is optimum for 80 meters. 120' and your low angle will skip right over their heads. Plenty of folks on 80 use dipoles at 30' year after year. Same folks are not DX hounds.


Remember that maximum radiation takes place at the current maximum points of the antenna. Put up 130 feet center fed and the center will be doing most of the work on 80. Same antenna on 40 radiates most from halfway out on both wires.

The trick with a multiband antenna is to use good balanced line. Twinlead and windowline both suck when wet. Use real open wire line with plastic or ceramic spreaders. Feed with a good quality tuner designed for a wide range balanced load.

Double Bazooka is a cool name for a unnecessarily heavy antenna which loses power deliberately to exhibit low SWR over a small increase in bandwidth over it's dipole cousin.

Reply With Quote
  #13  
Old 06-10-2009, 03:39 PM
Crotchety Old Bastard
iTrader: (0)
 
Join Date: Apr 2005
Location: Oklahoma
Posts: 6,915
W5LZ is on a distinguished road
Default


Now that's the best description of a double bazooka antenna that I've seen in a long time!
I'm also a fan of parallel feed lines. Not having found any of the 'bare' wire type ladder line in quite a few years, I use what I can find. Did the 'DIY' ladder line -once-, don't plan on doing that again, I hope! Oooo, that's fun. Also found that while it's wet, just as said, it does change tuning over a fairly wide range. Using wax, etc, does not help things, since most waxes are conductive to some extent. Just like your millage, that 'conductivity' changes.
Best advice for a tuner when using ladder line is the 'biggest' one you can find. Not big as in power, but component 'size', usable range of tuning. Oh well, lot's of little thingys can make a big difference...
- 'Doc

Reply With Quote
  #14  
Old 06-10-2009, 06:05 PM
guardian of freedom
iTrader: (0)
 
Join Date: Jun 2005
Location: daegaba system
Posts: 803
rfoverlord is on a distinguished road
Default

Tony,
you might want to take a gander at this.
http://www.eham.net/articles/21682
__________________

If you run, you'll only die tired.
CDX-251,2SF251,AE926, N9MSH

Reply With Quote
  #15  
Old 06-11-2009, 09:36 PM
Lazybones1222's Avatar
W9WDX Amateur Radio Club Member
iTrader: (1)
 
Join Date: Apr 2005
Location: Tampa Bay Florida
Posts: 959
Lazybones1222 is on a distinguished road
Thumbs up

Quote:
Originally Posted by Beetle View Post
Center fed doublet as long and as high as practical. Balanced feedline directly to the tuner. Build the antenna yourself and use a good commercial feedline and quality insulators. For multiband operation it doesn't get much simpler or more effective. Might need to experiment with feedline length for some bands; might not.

All antennas are compromises in some way, and this one is no exception.
That's what I run. Love it. Simple. Works great. Cheap to build.

Reply With Quote
  #16  
Old 09-13-2009, 03:23 PM
Jock Supporter
iTrader: (8)
 
Join Date: Feb 2008
Posts: 7,534
mackmobile43 is on a distinguished road
Default

What is the minimum length of coax required to operate a 102' G5RV?

Reply With Quote
Reply

Bookmarks
Worldwide Radio Forum



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 05:59 AM.


Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Worldwide Radio Forum