[OZAPRS] 2M 1/4 Wave antenna

[Chris Hill]

Hi,

The top two results from my search on Google seem pretty relevant:

http://www.hamuniverse.com/2metergp.html

http://www.northcountryradio.com/Articles/groundplane.htm



You really can't go too wrong...



73,



Chris
vk6kch



-----Original Message-----
From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
Behalf Of Damien Gardner Jnr
Sent: Sunday, 14 January 2007 6:51 PM
To: VK / ZL APRS Users; Aprssig
Subject: Re: [OZAPRS] 2M 1/4 Wave antenna

----- Original Message ----- 
From: "Andrew Rich" <vk4tec at tech-software.net>
> Searched for ages on google, looking for a 1/4 wave vhf calculation for
> 145.825 MHz
> I remember that the 45 degree radials had to be a ratio longer or
shorter
> than the vertical element.
> 1/4 Wave antenna = 51.43 cm

It's been years since I built a 1/4 wave antenna, and a mate has my RSGB 
antenna book at the moment, but I always used to take 5% off the
calculated 
length of the antenna.. I think for a bit of impedance matching, though
it's

been WAY too long to say for sure :) I do remember that the radials were 
exactly 1/4 wave, and by adjusting the down-angle on them, you could tune 
the 1/4 wave to more closely match your 50 ohm coax..? (nominal on a 1/4 
antenna is 37 ohm or something iirc?)

Google seems to actually be suprisingly thin on 1/4 wave antenna info.. 
Really gotta get my RSGB back :)

Cheers,

Damien
--
Damien Gardner Jnr
VK2TDG/VK2DGJ. Dip EE. StudIEAust
Home: rendrag at rendrag.net -  http://www.rendrag.net/
Play: vk2tdg at pinegap.net  -  http://pinegap.net/
--
We rode on the winds of the rising storm,
  We ran to the sounds of thunder.
We danced among the lightning bolts,
  and tore the world asunder 


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