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 <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> 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> 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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