[Elecraft] Antennas for use with Elecraft T1 ATU

[Karl Larsen]

Don Wilhelm wrote:
> Kieth,
>
> A dipole cut for 40 meters will provide a high feedpoint impedance on 20 -
> and the L network used in the Elecraft tuners do not do high impedances very
> well.
>   
    I find the T1 does very well with a very high impedance. I end feed 
1/2 wave wire connected right to the T1 with a counterpoise and it 
matches right up! I ran a test and the T1 can match a 4700 ohm resistor. 
So it's not bad with high resistance.

73 Karl

> Of course, all that does depend on your feedline length as well as the
> flattop length - the feedline will act as an impedance transformer when it
> has SWR on the feedline, so unless you can state the length and impedance
> and velocity factor of your feedline, we cannot answer your question with
> any degree of certainty.
>
> I use an antenna cut at 22 feet each side of center with a 25 foot feedline
> for portable use, and it works FB on all bands except that it is marginal on
> 30 meters - adding an additional 10 feet of feedline allows it to tune 30
> meters just fine with the Elecraft L network tuners.
>
> I deploy my portable antenna as a horizontal dipole, or and inverted VEE, or
> as a vertical with a single radial, whichever is convenient for the location
> I have at the moment - I do carry a 32 foot collapsible mast to deploy the
> antenna if I have no other suitable supports.
>
> 73,
> Don W3FPR
>
>
>   
>> -----Original Message-----
>>
>> Thanks for the quick response.  For a field dipole I could use
>> that in an inverted V format I assume?  I did purchase a
>> collapsable pole to try some of those out.  If I used ladder line
>> or twinlead....would I need a balun in-line before connecting to
>> the T1?
>>
>> If I understood you correctly, I could cut the dipole for 40M and
>> then use the T1 to use it on other bands.  For my base setup I
>> use a dipole setup and it works well on multiple bands....I am
>> just not real clear on how to make this work on a portable
>> setup with the T1 ATU.
>>
>> Is there any special twinlead or ladderline I should stock for
>> these projects?  I hope to try a bunch of antenna designs for
>> different locations and learn from them...so I may as well stock
>> some wire.
>>
>> I think a recent QRP Quaterly that had a plan for a portable
>> vertical...I will check it out.
>>
>> Thanks again for all the advice.
>>
>> 73 de Keith KB3ILS
>>
>>     
>
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