[Elecraft] K2 + ATU + Loop antenna in the attic

[Doug Person]

I have an array of dipoles, some trapped, some using W9INN style 
chokes.  I also have a tribander.  But the antenna that gets used all 
the time is 160' doublet fed with 300 ohm line which goes into a DX 
Engineering 1:1 balun with short piece of RG-8 type coax coming into the 
house.  The tuners on the K1, K2, and K3 will tune it to any band.  I 
have experimented a great deal with fan dipoles.  They certainly work.  
And also Off-Center fed antennas; they also work well. Loops a good too. 
I have a notebook with 40 years of wire antenna experiments.  For me the 
most satisfying antenna so far is the simple doublet.  It will always be 
the first antenna I recommend.  With the great tuners in the Elecraft 
gear, it seems like a no-brainer.

73, Doug -- K0DXV

On 4/15/2011 6:16 PM, Ron D'Eau Claire wrote:
> I played with a fan dipole back in the 1960's, and played and played and
> played trying to get a decent (less than 3:1) match to 50 ohm coax. Never
> was happy.
>
> That experiment taught me the efficiency, ease and simplicity of a doublet*
> fed with open wire line. Working out the process of getting the open wire
> line into the shack wasn't nearly as difficult as trying to get the antenna
> to present a decent match to the coax, and it was a wonderfully efficient
> and effective all band antenna mounted at an "inverted V" with the apex at
> 50 feet.
>
> BTW, my doublet was 100 feet end-to-end and worked beautifully on 160
> through 10 meters. Granted, at so close to the ground the radiation was
> mostly straight up on 160 but on that band I was mostly interested in
> working locals out to 100 miles or so. We had a lot of mobiles active on 160
> back then as well as fixed stations. And none of the rude nonsense so often
> found on 75.
>
> Ron AC7AC
>
> *Wire fed at the center but not necessarily a "dipole" - i.e. 1/2 wavelength
> long - on any band.
>
> -----Original Message-----
> Subject: Re: [Elecraft] K2 + ATU + Loop antenna in the attic
>
>    Alan,
>
> Sorry to hear about your lack of success with the fan dipoles.  I have
> three of them - one for 80 and 40, another for 30, 17 and 12m, and yet
> another for 20, 15, and 10.  They work very well.
>
> My "secrets" - space the wires for each band away from one another - my
> 80 and 40 antennas are at right angles to each other, so there is little
> of any interaction.  The other two have the wires spaced about 1 foot
> apart using CPVC pipe with holes drilled in them (wires through the
> holes) to maintain the spacing.  PVC would work too, but is heavier).
>
> The antennas do interact, so plan ahead, you will have to do some "cut
> and try" pruning.  Tune the lowest band or resonance first, and then the
> next band higher in frequency.  Trying it the other "way 'round" is an
> exercise in futility (been there, done that, and have the scars).
>
> I usually consider 3 bands on one feedline the limit of my patience, but
> this last weekend I helped a friend construct an antenna with 4 wires -
> 80, 40, 20, and 10 meters.  It was a bit of a pain to tune, but it
> worked out well.  Cut the wires at least 10% long and prune as required.
>
> One other point - do not use separate wires for bands that are close to
> the 3rd harmonic of another band - in other words, for HF, do not put a
> 30 meter radiator on a feedline that contains an 80 meter wire, and do
> not put a 15 meter wire on a feedline that also has a 40 meter wire.
> The lower band antenna may be usable on the 3rd harmonic (likely with a
> tuner), but trying to combine those two wires will result in even more
> frustration.
>
> 73,
> Don W3FPR
>
> On 4/15/2011 6:15 PM, Alan D. Wilcox wrote:
>> FWIW, see my fan antenna at
>> http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole
>> A bright idea that didn't work out so well!
>>
>> Cheers, Alan
>>
>> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
>>
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