Wes,
It was late last night and I misinterpreted the sign - so yes, that was
what my eyes at that time did to me.
Your solution is more correct in the light of day.
73,
Don W3FPR
On 1/3/2011 9:06 PM, Wes Stewart wrote:
> Don,
>
> So you want to add +j1000 to +j1000 to get zero?
>
> Wes
>
> --
Don,
So you want to add +j1000 to +j1000 to get zero?
Wes
--- On Sun, 1/2/11, Don Wilhelm wrote:
> Wes,
>
> I don't know about the -j501, but Kirchoff tells me that a
> series Xl =
> j1000 alone will cancel the +j1000 in the shack feedpoint
> (your example)
> leaving a 50 ohms pure resis
Many thanks, gentlemen, for the many words of wisdom.
The topic, so far as I am concerned at least, is now closed!
73 Stephen G4SJP
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Wes,
I don't know about the -j501, but Kirchoff tells me that a series Xl =
j1000 alone will cancel the +j1000 in the shack feedpoint (your example)
leaving a 50 ohms pure resistive load, no need for the shunt element.
Since the absolute value of the Low Pass L-net impedance requires that
Rl
Sort of sounds logical but it's wrong.
Let the load in the shack be 50 +j1000.
A low-pass L-net with a shunt Xc = -j501 and series Xl = j1000 will do it.
Wes N7WS
--- On Sun, 1/2/11, Don Wilhelm wrote:
> As you mentioned, the matching range of the KAT3 becomes
> greater as the
> frequen
Don't you mean "to the transmission line"?
A quarter-wavelength line between the antenna and tuner makes that -j into a +j.
Wes N7WS
--- On Sun, 1/2/11, Tony Estep wrote:
>
> The antenna can be way shorter than 1/2 wave
> and still tune up
> fine. No loading scheme is needed. A short antenna
Chen
Thanks for that supporting addition, and for your work on the Smith
Chart showing the KAT3 matching range for 160 meters. It is all a
matter of the physics of the situation.
As you mentioned, the matching range of the KAT3 becomes greater as the
frequency is increased.
That fact is oft
On 1/2/2011 2:39 PM, Tony Estep wrote:
> A short antenna just presents a
> capacitive reactance (a -j value) to the tuner, which in my experience the
> KAT3 has always been able to deal with.
Well ... I think it sort of depends on the antenna and the length of the
feedline if it's surge impedanc
On Jan 2, 2011, at 5:52 PM, Kok Chen wrote:
> In the case of the K3, you may have to try everything up to about 3/4 of a
> wavelength since the green and blue parts are not symmetrical. (Yes, 3/4
> wavelength at 160m is no fun :-).
My mistake, that should be "everything up to 3/8 of a waveleng
On Jan 2, 2011, at 5:52 PM, Kok Chen wrote:
> You can see what Don means by taking a look at this figure (KAT3 at 1.8 MHz,
> with Smith Chart centered at 50+i0 ohms):
>
> http://homepage.mac.com/chen/Technical/Tuner/tuner1.8.png
I should add that, if memory serves (it has been a while ago that
On Jan 2, 2011, at 4:01 PM, Don Wilhelm wrote:
> Adding or subtracting a 1/8 wavelength of feedline
> will often bring it into range, and that is normally the easiest
> solution if the only thing you are considering is the ability of the
> tuner to produce a match.
You can see what Don means
Even if you can tune a 40m wire on 160, that doesn't mean it will work
well. In my experience, short wires for the low bands are an exercise
in futility.
Barry W2UP
--
Barry Kutner, W2UP Lakewood, CO
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Elecraft mailing
The length of the radiator is only half the story. Unless the
feedline is matched to the impedance at the antenna feedpoint, there
will be SWR on the transmission line.
When there is SWR on the transmission line, the type of line and its
length become important when comparing whether any give
The real issue with verticals over bad "ground" of that sort is to
couple as little of it as possible. There is good evidence that DENSE
elevated radials are effective over really bad earth. Since "dense"
and "elevated" coupled together can easily be one of those
easy-to-say-and-don't-dare-do sit
It's very patchy: there are areas of huge clay deposits stretching for miles
and very deep; I've forgotten the geological term for it, but I understand
it was pushed into place by the last ice age; good for low loss low angle
radiation I understand. There are also large areas of sand stone whic
On Sun, Jan 2, 2011 at 3:18 PM, Dr. Detlef Petrausch wrote:
> I use a 40.8 m long windom and it's no problem to tune to a swr abt. 1.2
> with the KAT3 on the 160m band
Yep, similar results here. I have used 7 different ATUs and the KAT3 is the
best by far. The antenna can be way shorter than
ill easily accept his experience that
verticals don't work well there.
Willis 'Cookie' Cooke
K5EWJ
From: Jim Brown
To: elecraft@mailman.qth.net
Sent: Sun, January 2, 2011 3:42:12 PM
Subject: Re: [Elecraft] [K3] KAT3 and 160 with 40m long doub
On 1/2/2011 12:03 PM, Stephen Prior wrote:
> I don't have a good enough ground to feed the antenna as a Marconi so my
> options other than lengthening the antenna are rather limited.
Don't give up so easily. In Chicago, I used a big wrought iron fence
plus a dozen or so 30 ft long wires as count
That's not correct.
I use a 40.8 m long windom and it's no problem to tune to a swr abt. 1.2
with the KAT3 on the 160m band.
73 Detlef, DL7NDF
Am 02.01.2011 20:51, schrieb Jim Brown:
> On 1/2/2011 11:31 AM, Stephen Prior wrote:
>> In the meantime I would be pleased to hear any
>> comments.
> Th
I used a low and bent doublet of 2 x 88ft per section for a while and it
"tuned" up amazingly well on all bands 160 to 10 with the KAT3. As a rule I
like to use multi-band doublets away from any obvious in-band resonances, so
that it doesn't experience very high Z anywhere, so, adding a bit on
I guess I feel rather foolish. Why I should have expected the KAT3 to
cope I don't know, perhaps I have been swayed by the reports of others who
have claimed that the KAT3 would load anything anywhere! I shall have to
lengthen the antenna.
I don't have a good enough ground to feed the antenna as
On 1/2/2011 11:31 AM, Stephen Prior wrote:
> In the meantime I would be pleased to hear any
> comments.
The condition you describe is not at all surprising for an antenna
that's half the length it needs to be for an acceptable match.
73, Jim K9YC
will probably tune for you.
Willis 'Cookie' Cooke
K5EWJ
From: Stephen Prior
To: elecraft
Sent: Sun, January 2, 2011 1:31:06 PM
Subject: [Elecraft] [K3] KAT3 and 160 with 40m long doublet
I have only just recently added the KAT3 and I'm very im
Stephen,
What is the SWR without the tuner ?
73 Ken K5DNL
--
--- On Sun, 1/2/11, Stephen Prior wrote:
> From: Stephen Prior
> Subject: [Elecraft] [K3] KAT3 and 160 with 40m long doublet
> To: "elecraft"
> Date: S
I have only just recently added the KAT3 and I'm very impressed with it, but
given the praise heaped upon it by others I'm slightly surprised that the
best VSWR I can get on 160m is about 8:1. The antenna is approximately a
doublet which is a half wave long on 80m I say 'approximately' as it's
s
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