[Elecraft] Small QRP antenna

[Bill Johnson]

Having "only" 5 watts doesn't change the need for proper termination and
antenna match.  5 Watts, or any wattage, for that matter can be a problem.
5 watts MAY make the problem less physically an problem.  

73,
Bill
K9YEQ

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim
Brown
Sent: Thursday, December 29, 2016 12:59 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Small QRP antenna

Nothing in this post is true. Optimum length for a counterpoise is a quarter
wave. Radials are a form of counterpoise, and their optimum length is also a
quarter wave. More radials reduce ground losses. 
Failing to provide an adequate counterpoise will cause the antenna's return
current to flow on your coax, which makes the rig hot with RF. 
That's not much of a problem with 5W, but it can be a very big deal with
100W or more.

Of course, it does depend on what you mean by "much" and "minimal." 
Inadequate counterpoise or radial systems can easily reduce you signal by 6
dB. That's an S-unit, and it reduces your 5W signal to 1.25W.  I wouldn't
call that minimal or "not much."

73, Jim K9YC

On Thu,12/29/2016 7:30 AM, Fred Moore wrote:
> With an end fed 1/4 wave you only need a counterpoise that is about 
> .05 wave length.  it can be the coax or another counterpoise.  
> Although a counterpoise has some effect on radiation pattern of a quarter
wave
> radiator, it is minimal.   You won't see much improvement in performance
> by going above .05 wave length..  it's not worth the trouble to 
> increase the counterpoise length..


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