[Elecraft] Small QRP antenna

[Richard Fjeld]

With reference to below, I have a question please.  I put up a quarter 
wave inverted-L for 160 meters.  My only counterpoise is the ground rods 
at the base of the tower.  I wasn't expecting much, but it does so well 
I'd like to add a decent counterpoise.

If I bury a quarter wave wire, would it be best to put it under the 
Ariel wire, or opposite from it?
Thanks in advance,
Dick, n0ce


On 12/29/2016 10:16 AM, Don Wilhelm wrote:
> I think this is mixing up 1/2 wave radiators and 1/4 wave radiators.
> To be resonant, a 1/4 wave wire needs another 1/4 wave "counterpoise" 
> - think of a center fed dipole - it has 1/4 wave on each side whether 
> one side is a monopole (vertical) and the other 1/4 wave is an 
> elevated radial or buried radials of indeterminate length, or whether 
> it is a dipole with the center in the air.
>
> A 1/2 wave radiator fed at the end theoretically does not need any 
> counterpoise, but in practice it does - but only needs to be about 
> 0.05 wavelength long.
>
> Refer to some antenna books (the ARRL has a good one) or the ARRL 
> Handbook for good information about basic antennas.
>
> 73,
> Don W3FPR
>
> On 12/29/2016 10:30 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..   Fred
>>
>>
>> On 12/29/16 9:01 AM, mjisted wrote:
>>> Looking at your text message on the elecraft board. About a half wave
>>> length ...here is a question for you. I'm going to put up a half
>>> wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter
>>> wave length of counter point as a radiator ground plane. ..
>>> The. ..G0MVP.
>>>
>>> mjisted at btinternet.com
>>>
>>>
>>> Sent from Samsung Mobile
>>>
>>>
>>> -------- Original message --------
>>> From: Fred Moore
>>> Date:29/12/2016 13:04 (GMT+00:00)
>>> To: elecraft at mailman.qth.net
>>> Subject: Re: [Elecraft] Small QRP antenna
>>>
>>> Don,
>>>
>>> Thank you very much, for pointing out a very common issue that gets
>>> mixed up into discussions.  Your point is so valid the random wire
>>> always seems to get mixed into the 1/2 wave discussion for some
>>> reason..  and should never be mixed together.  you are absolutely
>>> correct..   thanks again regards..  Fred
>>>
>>>
>>> On 12/29/16 12:33 AM, Don Wilhelm wrote:
>>>> Scott,
>>>>
>>>> If the radiator is not a half wave long, it is not a "half wave".
>>>> Yes, a random length wire may work, but please do not call a random
>>>> length a half wave - the length of a half wave is quite specific.
>>>> Similarly, a quarter wavelength is a specific length at a particular
>>>> frequency.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> On 12/28/2016 11:20 PM, K9MA wrote:
>>>>> The counterpoise for an end fed half wave (or multiple) really 
>>>>> doesn't
>>>>> have to be anywhere near a quarter wave long.
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>>>
>>> -- 
>>> Fred Moore
>>> email: fred at fmeco.com
>>>        fred at safes.com
>>> phone:  321-217-8699
>>>
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