[Elecraft] AX1 Loaded Whip Antenna - Elevation and Counterpoise?

Wed Aug 7 22:29:04 EDT 2019

Then you'd be using the T1 to partially drop the SWR on the coax, but it 
still wouldn't be anything close to 1:1 unless the T1 has a much broader 
range than the tuner in the KX2.  You'd still have some additional coax 
loss due to SWR (but less loss, of course) and you'd still need the 
tuner in the KX2 to get a match that wasn't a problem for the KX2.

I have to wonder how much loss there is in two tuners each trying to 
match a really bad load, and it still seems to me that the better 
approach if you're worried about every dB is to use a better antenna.  
Using a really short whip like the AX1 with 50 feet of coax and two 
tuners seems like a poor choice of tradeoffs.

73,
Dave   AB7E

On 8/7/2019 6:39 PM, Wayne Burdick wrote:
> The SWR could easily exceed 15:1, depending on the operating frequency (short loaded whips can be very narrow banded) and other factors that apply to portable operation such as radial configuration, ground characteristics, and antenna height.
>
> Even 2 dB matters when you're using QRP.
>
> Wayne
> N6KR
>
>
>> On Aug 7, 2019, at 5:13 PM, David Gilbert <xdavid at cis-broadband.com> wrote:
>>
>>
>> Rather little of this discussion makes sense to me.
>>
>> Let's look at this realistically:
>>
>> 1.  The antenna tuner in the KX2 is rated to be good up to 10:1 SWR.  Let's assume it's good to 15:1.
>>
>> 2.  Let's assume you're using a decent cable for portable operation like RG-8X.
>>
>> 3.  Let's assume that the length of your coax when operating portable is not much more than 30 feet long.
>>
>> 4.  Let's assume under the current solar flux conditions you're spending most of your time on 20m or lower in frequency.
>>
>> 30 feet of RG-8X has a loss of 0.4 db or less for that length at those frequencies, and per the charts in the link below the additional loss due to a 15:1 SWR is no more than 2 dB.
>>
>> http://www.astrosurf.com/luxorion/qsl-transmission-line2.htm
>>
>> Maybe it's just me, but I don't think that justifies dragging along a remote tuner.  You could recover a heck of a lot more dB by simply bringing a somewhat larger portable antenna.
>>
>> 73,
>> Dave   AB7E
>>
>>
>>
>> On 8/7/2019 3:57 PM, Phil Hystad via Elecraft wrote:
>>> Sounds like an idea worth trying — I have always wondered about the coax loss between my KX3/KX2 and my portable antenna no matter which one it is (i.e. AX-1, Wire and counterpoise wires, Buddipole, etc.).
>>>
>>> But, really glad I did not sell the T1 on several occasions of thinking about selling it.  I have not used my T1 since I sold my KX1 almost three years ago.
>>>
>>> phil, K7PEH
>>>
>>>> On Aug 7, 2019, at 10:23 AM, Wayne Burdick <n6kr at elecraft.com> wrote:
>>>>
>>>> I think a T1 at the base would make a noticeable difference if the coax were more than a few feet long and the whip's resonance well removed from the target operating frequency. Short whips can be extremely narrow-banded.
>>>>
>>>> Wayne
>>>>
>>>>
>>>>
>>>>
>>>>> On Aug 7, 2019, at 7:40 AM, Don Wilhelm <donwilh at embarqmail.com> wrote:
>>>>>
>>>>> Bret,
>>>>>
>>>>> Yes, the T1 mounted at the antenna will reduce the potential loss in the coax.
>>>>>
>>>>> Will you notice the difference?  Maybe or maybe not.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>> On 8/7/2019 7:54 AM, MaverickNH wrote:
>>>>>> It comes to mind I have an Elecraft T1 ATU I might try attaching directly to
>>>>>> the base of the AX1 rather than relying on the KX2 ATU 25-40ft from the
>>>>>> antenna. I try to operate closer but sometimes have to run that RG58 to
>>>>>> clear obstructions. Thoughts?
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