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

David Gilbert xdavid at cis-broadband.com
Wed Aug 7 21:30:16 EDT 2019


Doesn't much matter.  You're still talking a 3 dB difference at most (50 
feet vs 30 feet), and while I will be the first to argue the benefit of 
every single dB for normal station operation (see 
http://www.ab7e.com/weak_signal/mdd.html), I don't understand the angxt 
over that 3 dB for portable operation.  If that's actually a concern, 
bring a better antenna.

73,
Dave   AB7E


On 8/7/2019 5:34 PM, Phil Hystad wrote:
> Some points…
>
> “…dragging along a remote tuner”
>
> Surely you are kidding or you get the award for hyperbole of the day.  The T1 fits in my shirt pocket!  It is zero effort to bring — no “dragging” required.
>
> And, I operate with 50 feet of coax because carrying multiple different lengths of coax on various trips where I operate portable does get into dragging.  There have been some situations where 50 feet has not been enough such as in one national park where the convenient picnic table was quite a distance from the nearest convenient tree.
>
> phil, K7PEH
>
>> 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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