Small QRP antenna question

[Terry]

Hello Group,

 

I currently use a doublet about 63 ft. on each side feeding 300 ohm twin
lead line into an Elecraft balun, then coax to my KX3.

 

I am going to be going to New Zealand for about three weeks during February,
and I am seriously considering taking my KX3 with me and operate N7TB/ZL.  I
just don't want to take the doublet because of size.  I have one of the BNC
to binding posts adapters for my KX3, and that seems like the best solution,
I just don't know how long my antenna wire should be, or the counterpoise.
I would appreciate any suggestions.  I would like to have the ability to
operate 80, 40, 30, 20, but I could get by without 80 meters.  

 

I would also be interested to find out from any Kiwi operators what the
current band conditions are in NZ.  It will be later in the Summer in the
Southern Hemisphere when I am there, so I would hope conditions on the 80
and 40 meter bands will be better than what we are currently experiencing in
the No. Hemisphere.

 

Thanks in advance for any advice you can give me.

 

Very 73's,

 

Terry, N7TB

 

 

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[Michael Babineau-2]

If you want to cover 80m through 10m with a single wire try something in the range of 84 to 86 feet.
This length is not a multiple of a half wave on any of the ham bands so it will present a reasonable impedance
that can be be matched with a tuner and not surprisingly this is the W3EDP length.

If you don’t care about 80m then the suggested 26 to 29 foot wire will work great (I personally recommend 28 to 29 feet as I have found that
a 26 foot wire is sometimes a bit harder to match on 40m depending on how it is deployed).

Ground radial length isn’t critical, but i suggest at least 1/8 wave on the lowest frequency of operation and more is better.
I normally use 5 radials made out of a 20 foot length of 5 conductor computer ribbon cable with all wires shorted together at
one end and connected to a single banana plug. You then unzip the wires from the end opposite the banana plug so that you only have
about 4 feet at the banana plug end that is still ‘zipped”.  This makes it convenient to route the radial wires off  a picnic table etc. before they
splay out on the ground.  When packing up I just pull all of the wires straight together and clip them together at the unzipped end with an IKEA
bag clip before rolling them up.  I use a 5 conductor cable as that is about my patience limit for radial deployment ;-)

Cheers

Michael VE3WMB / VA2NB (KX1, K1, K2)

>From: Walter Underwood <[hidden email] <mailto:[hidden email]>>
>Subject: Re: [Elecraft] Small QRP antenna question
>Date: December 27, 2016 at 2:12:09 AM GMT-5
>To: Elecraft Reflector Reflector <[hidden email] <mailto:[hidden email]>>


>For 80 meters, try a 53 foot wire in the air. For 40 meters and up, try a wire 26 to 29 feet long.

>I use a 16 foot wire laying on the ground. That length either isn’t critical, or changes electrical length due to capacitance to RF ground at every site. Or both. Whatever, the ATU seems to deal >with it.

>I assume you have the ATU.

>I have been using camping clothesline reels for the wire, but they don’t wind up very smoothly. I just got some “midi” wire winders from SOTAbeams (http://www.sotabeams.co.uk/midi->winders/ <http://www.sotabeams.co.uk/midi-%3Ewinders/><http://www.sotabeams.co.uk/midi-winders/ <http://www.sotabeams.co.uk/midi-winders/>>). The regular winders are longer than my KX3. Haven’t used them yet.

>wunder
>K6WRU
>Walter Underwood
>CM87wj
>http://observer.wunderwood.org/ <http://observer.wunderwood.org/> (my blog)
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]