[Elecraft] KAT2 with EFHW antenna

[David Gilbert]

I'm not sure I see the advantage.  A full wave end fed antenna would 
theoretically have the same very high feedpoint impedance, and would 
additionally blow most of it's radiated energy at a fairly high angle 
off the ends of the antenna instead of broadside at a lower angle.  If 
you find it that easy to tune, I suspect that electrically it really 
isn't that close to a full wavelength ... possibly because of coupling 
to earth (if it is low) or nearby structures.  Either that or there is a 
lot of loss in the system somewhere.

73,
Dave   AB7E





On 8/24/2011 2:14 PM, Niel Wiegand wrote:
> Phil,
>
> You might try a 67' length of wire (EFFW antenna). I've used that (and a
> 32' EFHW) on 20 a lot with my K1 with the KAT1 installed...tunes to
> close to 1:1 just fine.
>
> Have fun at Crater Lake. There are some neat places along the rim for
> hamming. It's a 2000 mile drive (one way) for me but I've gotten there
> twice within the past several years. See
> http://www.prismnet.com/~nielw/qrp/CraterLake_july04.jpg  and
> http://w0vlz.blogspot.com/2009/08/after-three-weeks-5300-miles-and-12.html
>
> 73,
> Niel - W0VLZ
>
>
>
>> Message: 2
>> Date: Tue, 23 Aug 2011 16:00:17 -0700
>> From: "Phillip Shepard"<phils at riousa.com>
>> Subject: [Elecraft] KAT2 with EFHW antenna
>> To:<elecraft at mailman.qth.net>
>> Message-ID:<LNEJJGGBOPIGKCIKMCKDEEGOIAAA.phils at riousa.com>
>> Content-Type: text/plain;	charset="us-ascii"
>>
>> I have been using my K2 with an MFJ tuner to feed an end fed halfwave wire
>> for portable use (like SOTA).  The 20m antenna is 33' long and I use one or
>> two 16' counterpoise wires.  It seems to work well for what it is and 10W.
>> I just built and installed the KAT2 ATU into the K2 to lighten my pack by
>> the loss of the MFJ.  The KAT2 tuner checked out fine on the bench, but it
>> had a very hard time getting a good match to the antenna.  In AUTO mode, it
>> only got the SWR down to about 5:1.  I put it in ALT mode, and it spent a
>> long time searching before it got down to between 3:1 and 4:1, depending on
>> the 20m frequency.  I added about 2" of wire to the antenna, and the tuer
>> got down to about 2:1 to 2.5:1.  I added another foot of wire (now 36'), and
>> it got down to about 1.5:1.  Five or six feet added yielded a perfect match
>> (1:1).  So I now have a 39' wire for 20m use.
>>
>> Is this normal?  Should the KAT2 be able to more easily match the 33'
>> halfwave antenna?  Thank you.
>>
>> 73,
>> Phl, NS7P
>>
>>