[Elecraft] Elecraft] KX2

[Fred C. Jensen]

I use an EFHW on 80-10, no dedicated counterpoise, no coax length rqmts.  However, NEC2 doesn't like a source at the open end of a wire so to model it, I have to put some counterpoise on the wire. Length not critical, 5-10 ft is fine.

73,

Fred K6DGW

David Gilbert <xdavid at cis-broadband.com> wrote:
>
>I'm confused why an EFHW should need a counterpoise.  If it needs a 
>counterpoise it isn't actually acting like an EFHW.  If it needs a 
>counterpoise that means there isn't enough choking impedance at the 
>feedpoint, and it means that the feedline is radiating with the 
>counterpoise acting as ... well, a counterpoise.
>
>Manufacturers state a minimum length feedline simply to have the 
>feedline losses help swamp out SWR variations along the line, and of 
>course to marginally lower the SWR.
>
>Dave
>AB7E
>
>
>On 7/14/2016 1:03 PM, Don Wilhelm wrote:
>> Andy,
>>
>> What happens if you connect to a dummy load?  Does the KX2 tune it 
>> properly?
>> If so, then you know the KX2 is operating into a 50 ohm load OK.
>>
>> Do you have an antenna analyzer?  If so, then connect it to the 
>> antenna feedline and look at the impedance - both real and reactive - 
>> as well as the SWR.
>> That will tell you whether the antenna is troublesome.
>>
>> You specifically said an EFHW - that should be a resonant antenna.  If 
>> instead you have a random length wire (not a halfwave), and what is 
>> the matching device?
>> Many EFHW antennas need a counterpoise to work - that is why many 
>> manufacturers state a *minimum* length feedline.
>>
>> If the problem is *not* the antenna, contact Elecraft support.
>>
>> 73,
>> Don W3FPR
>>
>> On 7/14/2016 2:40 PM, Andy Clift wrote:
>>> Just received my KX2, but unable to get it to tune an EFHW wire. I’ve 
>>> tried a home made one and then tried a SOTABEAMS MultiBander that 
>>> I’ve used successfully with an FT-857. I’ve checked the continuity in 
>>> the wire and also the continuity in the KX2 between the BNC connector 
>>> and where the wire connects inside the KX2 (as I removed this to fit 
>>> the end panels). Battery is at over 11v. Any ideas please?
>>>
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