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Re: "random wire" and the KX3 ATU

Posted by wayne burdick on Jun 27, 2012; 4:41am
URL: http://elecraft.85.s1.nabble.com/K3-KX3-Operating-Tip-APF-audio-peaking-filter-for-weak-signal-CW-work-tp7558208p7558244.html

Well done, Phil. Experimenting with antennas is half the fun, IMHO.

Wayne

On Jun 26, 2012, at 9:38 PM, Phillip Shepard wrote:

> As an example, I used a 40m Extended Double Zepp for field day.  
> This is an
> 180' wire center fed with ladder line.  My FD installation had about  
> 60' of
> ladder line hanging down to the rig.  Ordinarily, I would use a  
> toroid to
> make a balun to the rig, but I didn't have a suitable form in my  
> junk box,
> so I hooked the ladder line to a BNC to dual banana binding post  
> adapter.
> The KX3 ATU did fine in matching from 80 to 10m, except on 40m.  On  
> the
> other bands, the match was 1:1 or close, but on 40m, the tuner  
> struggled to
> get down to 3:1 or so.  I added a 33' "radial" wire to the ground  
> side of
> the banana adapter and ran it under the antenna, keeping it 2 to 3'  
> above
> the ground.  With this addition, the ATU could usually get close to  
> 1:1 on
> 40m. The antenna seemed to play well, so the efficiency must not  
> have been
> too bad.  I was impressed with the KX3 for many reasons, including  
> its ATU.
>
> 73,
> Phil, NS7P
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]]On Behalf Of Wayne Burdick
> Sent: Tuesday, June 26, 2012 9:09 PM
> To: Jeff Herr
> Cc: 'Elecraft Reflector'
> Subject: Re: [Elecraft] "random wire" and the KX3 ATU
>
>
> Jeff,
>
> The KXAT3 has a very wide tuning range and is specifically designed
> for use with random-length antennas. Typically any wire longer than
> 20' or so can be tuned up on 40-6 meters. A 74-foot antenna will
> probably be tunable to reasonable SWR on 160-6.
>
> A random wire antenna can work very well -- comparable to a vertical
> or dipole depending on the band, radiation angle, and your ground
> system (if the random wire is worked against radials).
>
> I use random wires almost exclusively. The KXAT3 does an excellent job
> with them. It will also do other magic tricks like make an 80-meter
> dipole work on all bands, or a 20-meter yagi work on 30-6 meters, etc.
> Efficiency will vary, but the transmitter will be happy.
>
> 73,
> Wayne
> N6KR
>
>
> On Jun 26, 2012, at 7:55 PM, Jeff Herr wrote:
>
>> I know folks who have had bad experiences using a "random" wire with
>> an ATU.
>>
>> Although I ordered a buddipole with the kx3 I still am interested in
>> getting
>> A 74 foot length of wire up in the pine trees (I will have a
>> counterpoise)
>> while up in the
>> Lassen national forest.....we go there a lot.
>>
>> When I mention this I am met with much skepticism.
>>
>> Am I way off base?  Is this beyond the capabilities of the tuner?
>> Is there a descriptive spec for the tuner that describes the range
>> of it
>> matching capability?
>>
>> WW6L
>>
>>
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