Scroll down to the original post. We were talking about a KX2 with an
internal antenna tuner. Presumably the tuner works as it should to
present the proper load to the finals.
73,
Dave AB7E
On 8/7/2019 5:29 PM, Mark Goldberg wrote:
You need to take into account the radio finals. When the SWR is high,
My KX3 cuts back because it gets too much reflected power. I expect
the KX3, and in fact any other radio or amplifier is similar. 15:1 is
about half the power coming back.
Regards,
Mark
W7MLG
On Wed, Aug 7, 2019 at 5:14 PM David Gilbert <xda...@cis-broadband.com
<mailto:xda...@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 <n...@elecraft.com
<mailto:n...@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
<donw...@embarqmail.com <mailto:donw...@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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