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-   -   Best 144/420 antenna for attic installation? (https://www.radiobanter.com/antenna/145408-best-144-420-antenna-attic-installation.html)

[email protected] July 21st 09 01:28 AM

Best 144/420 antenna for attic installation?
 
I would appreciate some recommendations for a 144/420 MHz pole antenna to be mounted in my attic. I
would like it to have radials so I don't have to put a metal plate under it.

Thank you for your suggestions.

orfus July 21st 09 05:50 AM

Best 144/420 antenna for attic installation?
 
Discone !!

wrote:
I would appreciate some recommendations for a 144/420 MHz pole antenna to be mounted in my attic. I
would like it to have radials so I don't have to put a metal plate under it.

Thank you for your suggestions.


Ian Jackson[_2_] July 21st 09 08:17 AM

Best 144/420 antenna for attic installation?
 
In message ,
writes
I would appreciate some recommendations for a 144/420 MHz pole antenna
to be mounted in my attic. I
would like it to have radials so I don't have to put a metal plate under it.

Thank you for your suggestions.


If you have the height, a dual-band J-pole?
--
Ian

Sal M. Onella July 22nd 09 07:11 AM

Best 144/420 antenna for attic installation?
 

wrote in message
...
I would appreciate some recommendations for a 144/420 MHz pole antenna to

be mounted in my attic. I
would like it to have radials so I don't have to put a metal plate under

it.

Thank you for your suggestions.


2m J-pole antenna is my recommendation. It delivers a reasonable match on
70cm, too. One drawback is the elevation pattern at 70cm -- the major lobes
are not at the horizon and much of the power is wasted if you're working
terrestrial. The antenna is about 57 inches tall and, as an end-fed dipole,
requires no ground plane. Google j-pole ham build and take your pick from
the many articles.

Of course you could make two j-poles, one for 2m and one for 70cm. They can
even be "stacked" all in one piece with separate feedlines. Tricky. Saw
one article years ago but can't find now.

A single structure dual band antenna is here in the ARRL Members Only
Section:
http://www2.arrl.org/members-only/ti...df/0010050.pdf

Sal



JB[_3_] July 22nd 09 05:10 PM

Best 144/420 antenna for attic installation?
 
wrote in message
...
I would appreciate some recommendations for a 144/420 MHz pole antenna to

be mounted in my attic. I
would like it to have radials so I don't have to put a metal plate under

it.

Thank you for your suggestions.

Most any mobile antenna may be mounted using radials vs. metal plate. Metal
plate need only be 19" radius disk for maximum performance. My favorite is
the Larsen NMO270. Overall height is 35" maximum with better gain than a
J-pole. You can make your own base radial mount or get one of theirs.
Available through AEA or HRO. the NMO is the Motorola mobile mount so
mounting solutions abound by a great many antenna manufacturers.


Dave Platt July 22nd 09 07:07 PM

Best 144/420 antenna for attic installation?
 
In article ,
Sal M. Onella wrote:

Of course you could make two j-poles, one for 2m and one for 70cm. They can
even be "stacked" all in one piece with separate feedlines. Tricky. Saw
one article years ago but can't find now.


Google "Copper Cactus" for that one.

I was never able to figure out the design details of the "single
feedline" Copper Cactus - it uses some internal matching stubs which
were not well-described.

The dual-feedline Copper Cactus worked out pretty well for me - I used
it for around 5 years (roof-mounted) until I replaced it with a
commercial tri-band antenna.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!


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