I recently bought an LDG AT600 Pro Automatic Tuner.
I seem to be able to get a low VSWR on 80 40 meters, but on 20, 15, 10
meters the best it will do is ~ 1.8:1.
My G5RV (It's really a Van Gordon 80 meter all bander fed with 450 ladder
line, 33 feet long, and then transitions to coax thru a
] on
behalf of Ron Midwin [ronmidwin...@gmail.com]
Sent: Friday, October 26, 2012 7:42 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] LDG antenna tuner with 132 foot balanced dipole similar
to a G5RV antenna
I recently bought an LDG AT600 Pro Automatic Tuner.
I seem to be able to get a low
Why not just help the tuner out a little? Put some inductance in series with
the
center conductor and see if it likes that better. If that doesn't work put
some C
in series and adjust it. Or some C across the line. Or some L across the line.
Or some L in series and C across the line. You
Ron -
This is not an area where I have much experience, but with 450 ohm ladder
line I would have thought you would use something other than a 1:1 balun.
A few years ago I experimented briefly with an 80 meter dipole, fed with
450 ohm ladder line. I tried it with a 1:1 balun and with a 4:1
Ron,
The antenna you have is basically a good one. The problem you get
into is that it's really an 80 meter dipole being used on all bands.
This has been a popular configuration for many years. The issue is NOT
SWR. The issue is transmission line loss in a high SWR situation. To
avoid
All,
There's a trick I learned from an antenna engineer acquaintance
recently for tuning 450 ohm feedline's with a 1:1 balun with 50 ohm
coax feeding the TX.
Here it is:
1. Assemble three RG11 coax lengths. One coax 6 feet 7 inches long,
one coax 6 feet long and one coax 9 feet long. From
What is the significance of using RG11 75 ohm coax vs 50 ohm? Sorry if this is
a dumb question.
Bob AF9W
On Oct 26, 2012, at 10:39 AM, N5GE wrote:
All,
There's a trick I learned from an antenna engineer acquaintance
recently for tuning 450 ohm feedline's with a 1:1 balun with 50 ohm
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Impedance matching. See
http://www.fourier-series.com/rf-concepts/smithchart.html May be
more than you wanted to know, but is easy to follow Smith Chart
Tutorials. And does explain why you might want to do this.
On 10/26/2012 01:23 PM, Bob Stephens
All other things being equal, 75-ohm cable has less loss per foot than
50-ohm cable. This assumes that the cables being compared have the same
diameter, length, operating frequency, etc. This is the primary reason
that cable TV systems, telco inside-plant cabling, and other similar
Sorry, meant to say 75-ohm, not 70-ohm in my previous post.
- Jim, KL7CC
On 10/26/2012 10:23 AM, Bob Stephens wrote:
What is the significance of using RG11 75 ohm coax vs 50 ohm? Sorry if this
is a dumb question.
Bob AF9W
On Oct 26, 2012, at 10:39 AM, N5GE wrote:
All,
There's a
The significance of the 75 Ohm line is a matching section that
introduces a reciprocal impedance that brings the SWR to 1:1, or nearly
so. However, this approach does not address the balanced to unbalanced
issue. And, this is generally a one band match. A 1:1 choke type balun
will still be
David,
I have seen several responses that suggest changes to your antenna
setup, but not one that I can warm up to.
The choice of a 1:1 balun vs. a 4:1 balun depends on the feedpoint
impedance and has nothing to do with the fact that the characteristic
impedance of the ladder line is 450 ohms
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