Using AC6LA's Line Loss calculator, and making the following assumptions:
Line impedance: 420 ohms, (1/4" copper pipe spaced 4 inches apart)
SWR at antenna: 14.0 (Z = 30 ohms)
Line attenuation: 0.0266 dB/100 feet (Duffy, "RF Two Wire Transmission Line
Loss Calculator",
n...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of K8TE
Sent: Saturday, July 18, 2020 9:57 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Matching resonant antennas
Lyn,
How do you measure your antenna's performance?
In many cases, not necessarily yours, anten
Lyn,
How do you measure your antenna's performance?
In many cases, not necessarily yours, antenna performance seems to be based
on countries worked, achieving WAS/DXCC, "It's way better than last year's
antenna.", or "I worked Pitcarin Island last week." None of these
"measures" are meaningful.
Walt and I corresponded quite a bit at one time. I sent my copy of the original
"Reflections" to him and asked him to sign it. He sent it back with a lovely
inscription. When Reflections II came out he sent me an unsolicited, inscribed
copy. He was quite pained by the ARRL's repudiation of
-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lyn Norstad
Sent: Saturday, July 18, 2020 1:10 PM
To: 'Ted Roycraft'; 'Elecraft List Server'
Subject: Re: [Elecraft] Matching resonant antennas
The 428 page "Reflections III" from 2010 is avai
...@mailman.qth.net] On Behalf Of Lyn Norstad
Sent: Saturday, July 18, 2020 1:10 PM
To: 'Ted Roycraft'; 'Elecraft List Server'
Subject: Re: [Elecraft] Matching resonant antennas
The 428 page "Reflections III" from 2010 is available here in PDF format:
http://www.w3pga.org/Antenna%20Books/R
craft
Sent: Saturday, July 18, 2020 10:22 AM
To: Elecraft List Server
Subject: Re: [Elecraft] Matching resonant antennas
Walter Maxwell’s interesting book, “Reflections”, has an in-depth
discussion on non-resonant antennas and tuners. Highly recommended.
73, Ted, W2ZK
On Sat, Jul 18, 2020 at 10:05 AM L
Sent: Saturday, July 18, 2020 7:37 AM
> To: l...@lnainc.com
> Cc: barrylaz...@gmail.com; elecraft@mailman.qth.net
> Subject: Re: [Elecraft] Matching resonant antennas
>
> What is changing is the radiation pattern. As the frequency increases the
> pattern becomes more sidelobes. S
Exactly.
-Original Message-
From: W2xj [mailto:w...@w2xj.net]
Sent: Saturday, July 18, 2020 7:37 AM
To: l...@lnainc.com
Cc: barrylaz...@gmail.com; elecraft@mailman.qth.net
Subject: Re: [Elecraft] Matching resonant antennas
What is changing is the radiation pattern. As the frequency
et] On Behalf Of Barry LaZar
> Sent: Friday, July 17, 2020 7:44 PM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] Matching resonant antennas
>
> Wes,
>
> You're correct that open wire/ladder line transmission lines are
> not a panacea. But, in the average ha
mailman.qth.net
>[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Rich NE1EE
>Sent: Saturday, July 18, 2020 5:09 AM
>To: elecraft@mailman.qth.net
>Subject: Re: [Elecraft] Matching resonant antennas
>
>This actually surfaces a question that I am currently wondering about with
rday, July 18, 2020 5:09 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Matching resonant antennas
This actually surfaces a question that I am currently wondering about with
my own system...what is measured performance here? I have a 40m EF wire
about 20m in the air, and I wonder how
This actually surfaces a question that I am currently wondering about with my
own system...what is measured performance here? I have a 40m EF wire about 20m
in the air, and I wonder how effective it is at radiating. I have good SWR, and
I get good signal reports, but wonder if that is the whole
: Friday, July 17, 2020 7:44 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Matching resonant antennas
Wes,
You're correct that open wire/ladder line transmission lines are
not a panacea. But, in the average ham stations, open wire does overcome
high losses with high SWR, or not so
@mailman.qth.net
Subject: Re: [Elecraft] Matching resonant antennas
Wes,
You're correct that open wire/ladder line transmission lines are
not a panacea. But, in the average ham stations, open wire does overcome
high losses with high SWR, or not so high SWR. What is needed is a look
at the ARRL
Wes,
You're correct that open wire/ladder line transmission lines are
not a panacea. But, in the average ham stations, open wire does overcome
high losses with high SWR, or not so high SWR. What is needed is a look
at the ARRL Antenna book for transmission line loss/100 ft. as a
function
I wrote about some of this in my paper ARRL Antenna Compendium paper on ladder
line 20 years ago. https://sadxa.org/n7ws/Ladder_Line.pdf
I've seen pictures of those SW transmitting plants and always assumed that they
must have been very efficient. Upon reflection---no pun intended---now I'm
Resonance is over rated. The problem of believing you must have a
resonant antenna arose with the use of coax cable began. High SWRs
causes high system losses.
Prior to the widespread use of coax, open wire was used and few antenna
systems were really resonant, and nor were they reflecting a
Interesting discussion:
But most of us probably tune our antennas for best SWR at the desired
frequency.
I have a dual-band 80-40m inverted-V with apex at 40-foot and 80m
wire tail at 20-foot. The separate 40m wire is spaced 6-inches from
the 80m wire with wooden dowels. I found by
If you want to pick nits then even a "perfect" dummy load doesn't match a
practical transmission line which has loss, hence has a reactive characteristic
impedance. :-)
Wes N7WS
On 7/16/2020 3:32 PM, donov...@starpower.net wrote:
Ken's statement that " a non-resonant antenna can have a 1:1
On 7/16/2020 9:57 PM, Ken WA8JXM wrote:
So pruning a horizontal dipole will never provide a 1:1 SWR except at 0.18
wavelength above ground (the ONLY elevation where the radiation resistance
is 50 ohms)? About 97 ft for 160m, 24 ft for 40m, 6 ft for 10m? A dipole
a half wave above ground has a
So pruning a horizontal dipole will never provide a 1:1 SWR except at 0.18
wavelength above ground (the ONLY elevation where the radiation resistance
is 50 ohms)? About 97 ft for 160m, 24 ft for 40m, 6 ft for 10m? A dipole
a half wave above ground has a 70 ohm radiation resistance and therefore
On 15/07/2020 20:30, Ken WA8JXM wrote:
> Conversely, a non-resonant antenna can have a 1:1 SWR.
On Thursday, July 16, 2020, 03:33:12 AM EDT, David Woolley
wrote:
> You can only have a 1:1 SWR at a single impedance. If the design
> impedance is purely resistive, that means you can only have
.net
Sent: Wednesday, July 15, 2020 7:30:58 PM
Subject: Re: [Elecraft] Matching resonant antennas
Yes, a resonant half wave dipole can have a feedpoint impedance of 5 ohms
to 90 ohms (SWR 10:1 to 1.8:1), but it's still resonant.
Conversely, a non-resonant antenna can have a 1:1 SWR.
Ken WA8JX
You can only have a 1:1 SWR at a single impedance. If the design
impedance is purely resistive, that means you can only have 1:1 for a
resistive and therefore on-resonance load (or one that can be treated as
having no reactive behaviour at the frequencies of interest - e.g. an
ideal dummy
Yes, a resonant half wave dipole can have a feedpoint impedance of 5 ohms
to 90 ohms (SWR 10:1 to 1.8:1), but it's still resonant.
Conversely, a non-resonant antenna can have a 1:1 SWR.
Ken WA8JXM
On Wed, Jul 15, 2020 at 12:34 PM Andy Durbin wrote:
> "A correspondent asked me why I needed to
Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Andy Durbin
Sent: Wednesday, July 15, 2020 11:33 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] Matching resonant antennas
"A correspondent asked me why I needed to tune a resonant an
"A correspondent asked me why I needed to tune a resonant antenna."
Perhaps the question should have been "why may you need to match the impedance
of a resonant antenna". The answer may be that not all resonant antennas are
50 ohm. Resonance only means that inductive and capacitive
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