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KX1 - We need to develop the ideal antenna

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Mike Morrow-3

KX1 - We need to develop the ideal antenna

Bob/AB5N wrote:

> I guess I have come to the conclusion that nobody has really run the gamut
> trying antenna designs for the KX-1.

And I guess I'd contest that statement. Testing portable HF antennas for
field and backpack use has been my principal ham interest for more than 30
years (but for general HF use, not just for the KX1).

> Its requirements are unique (the tuner etc).

I don't see anything unique about the KX1 application that doesn't apply
to any other HF rig. I usually operate a K1 with the KAT1 auto tuner, but
sometimes I go over to the dark side and use a mobile general coverage HF
transceiver. I use the same antenna for either, out in the field.

> OK, I'll "run the gamut"... with my goal being to fulfill the above
> criteria.

Thanks. I have a write-up for a very simple design that meets all your
criteria, plus is inexpensive and quick to home brew.

Erik/K7TV wrote:

> ...I have settled on a dipole with jumpers, and this is the best configuration
> yet. KK5F beat me to suggesting it here, but I am chiming in because the subject
> is interesting, and details are worth discussing.

As long as the antenna may be quickly accessed to alter the jumpers around the
insulators, and as long as some sort of support can be found or erected for the
ends and center, it is inarguably the very best approach for a dipole antenna.
The "insulator+jumper" approach used on my multi-band dipole performs better than
my permanently-installed home trap dipole.

> 1. My insulators are rectangular pieces of Lexan sheet, cut to about
> 0.25" x 0.5" x 1.75".

The insulator in my design is a 1.25-inch piece of 3/8-inch-OD PVC tubing,
with .125-inch holes drilled through it .25 inches from the ends. Only a
drill and a tubing cutter are required to completely fabricate one in a
matter of minutes. The 2.5-inch jumper around an insulator is permanently
affixed (soldered) on the down-leg side of the insulator, and utilzes a
1.5-inch alligator clip on the other end to close the jumper around the
insulator. I've never suffered a failure of any PVC insulator, which are
now 15 years old.

> 2. The wire I use is the extremely lightweight copperclad available
> from The Wireman...

My dipole assembly has been in service for 15 years, but I have used many
wire antennas in my experiments. The ***ONLY*** wire that I've ever used
that NEVER failed anywhere or anyhow is Flexweave-tm, also available from
Wireman (items 542 through 549) and other sources. It'll cost at least
$.21/foot (100 feet or more), but it is worth several times that, IMHO.
I use 14 ga. Flexweave, which consists of 168 fine strands that create a
wire that is extrememly flexible, durable, and a real joy to work.

> 3. My feedline is RG-58 from my Buddipole, which includes a lightweight
> balun using beads.

I prefer RG-8X, which is negligibly larger in diameter. I've used a balun
in earlier designs, and found it to be superflous for all practical purposes
in a temporary field installation. I do use a balun on my home dipole.

> 4. The configuration is inverted-vee, supported at up to 22 ft or so.

I tie the ends of my dipole off somewhere around eight feet above ground,
and use a set of dome tent replacement support rods to push the center
insulator up about nine feet above ground. It still works well, even this
low.

> 5. I store the antenna with feedline detached on two "Halo Winder"
> type spools designed for kite string.

I connect the jumpers around the 12 insulators, disconnect the coax at the
center conductor (which has a SO-239 connector), and roll the antenna up in
a one-foot diameter coil. I do the same for the coax. The 14 ga. Flexweave
is resistant to unspiraling into a complex jumble the way all other antenna
wire does when such a roll-up is attempted. It's all a very small volume
and weight for the backpack, and no sharp edges on anything!

> ...it turned out the wire had broken right at a solder joint.

Flexweave-tm will eliminate that possibility of failure. In fact, if some
Flexweave-type of wire is not used, failure due to wire fatigue is a
certainty...probably sooner than later...with such wire antennas.

If anyone is interested in a detailed description with photos of my seven-band
(10 through 40 meters) dipole, I can send a pdf file on request. It claims
no innovation and may be freely distributed, if desired. I have just revised
it to clarify some of the text and to add discussion of extending it for 80/75
and 60 meters. If any of the 60 or so list members that have received earlier
versions over the past decade want the update (Revision 3), just let me know.

73,
Mike / KK5F
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AB5N

We need to develop the Ideal Antenna!

Hi Guys-

Well, I'm in week two of enjoyment with my new KX-1. I did have a few problems in assembling, but
that is history.

This little rig has a simple receiver which has only half the sensitivity of a usual radio. As well, we are dealing
with 3-4 watts TX out max. We have to have an excellent antenna. I've tried the suggested 25 ft. long wire
with radials. Ah, it's not good enough. I even got some strange RX-feedback internally at some frequencies using it. I believe the criteria for an excellent antenna will be as follows:

1. Will match up well using the internal tuner on all four bands.

2. Has enough metal in the air to provide adequate microvolts to the RX - to make it function well without
being overloaded.

3. Provides some gain - or at least a clean predictable pattern

4. Is light, compact and easy to deploy.

My inkling is that a normal Carolina Windom may be the thing. I'll work on developing a micro-QRP version.

What doesn't work?

Classic G5RV (102 Ft) - will not load on any band with tuner.
Offset-Zepp fed with Coax (75'x25')

What say guys? Anybody have superb luck with an antenna yet?

Bob-AB5N

k4tmc

Re: We need to develop the Ideal Antenna!

Bob,

How about just a basic dipole? Or, a fan dipole that resonates on the appropriate bands.

73,
Henry - K4TMC

-----Original Message-----
From: AB5N <[hidden email]>
To: [hidden email]
Sent: Fri, May 13, 2011 1:31 pm
Subject: [Elecraft] We need to develop the Ideal Antenna!

Hi Guys-

Well, I'm in week two of enjoyment with my new KX-1. I did have a few
problems in assembling, but
that is history.

This little rig has a simple receiver which has only half the sensitivity of
a usual radio. As well, we are dealing
with 3-4 watts TX out max. We have to have an excellent antenna. I've tried
the suggested 25 ft. long wire
with radials. Ah, it's not good enough. I even got some strange RX-feedback
internally at some frequencies using it. I believe the criteria for an
excellent antenna will be as follows:

1. Will match up well using the internal tuner on all four bands.

2. Has enough metal in the air to provide adequate microvolts to the RX - to
make it function well without
being overloaded.

3. Provides some gain - or at least a clean predictable pattern

4. Is light, compact and easy to deploy.

My inkling is that a normal Carolina Windom may be the thing. I'll work on
developing a micro-QRP version.

What doesn't work?

Classic G5RV (102 Ft) - will not load on any band with tuner.
Offset-Zepp fed with Coax (75'x25')

What say guys? Anybody have superb luck with an antenna yet?

Bob-AB5N

--
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Don Wilhelm-4

Re: We need to develop the Ideal Antenna!

In reply to this post by AB5N

Bob,

Actually, a properly functioning KX1 has an MDS of better than -130 dBm,
so it actually is a sensitive receiver.

Some like the Carolina Windom, but I don't like any unbalanced antennas,
and have a high preference for center fed antennas, they are easier to
tame, and if the feedline leaves the antenna at right angles from the
center, seldom do "RF-in-the-shack" problems emerge.

The KXAT1 has a more limited range on 80 meters than the other bands
just because the total inductance and capacitance is limited - only 3
choices of each.

I would suggest a trap antenna with traps for 40 and 20 meters. Feed it
with balanced feedline cut a half wavelength (or multiple) on 80 meters
- the tuner should be able to match it on 30 meters and the half
wavelength of feedline on 80 meters should present a feedpoint impedance
close to that at the antenna center (50 to 75 ohms) for 80, 40, and 20
(assuming the traps are used).
I have not actually built such an antenna, but the theory says it should
work just fine. Keep the balanced feedline supported along its entire
length and don't forget that there is a velocity factor to consider when
determining a half wavelength - if you cannot do that, add a trap for 30
meters and feed it with any length of coax. Coaxial traps are not
difficult to build, and for QRP use, can even use RG174 on a piece of
1/2 inch PVC for a form. Doug DeMaw (SK) W1FB had information on
building traps like that in QST a very long time ago (try in the
1980s). Also see the W1FB Antenna Notebook and/or the article in QST
for Decenber 1984 page 37 by N4UU. Gary o'Neil N3GO also has some good
information about coaxial traps on the web (use Google).

I realize that a 135 foot long antenna is not "easy to deploy", so I
would suggest an alternative - build a coax fed trap antenna for 40, 30
and 20 meters (traps for 30 and 20), and carry along 2 33 foot lengths
of wire - insulators on one end and an alligator clip on the other -
when you want to operate 80 meters, add the wires to each end of the
radiator. You could carry that concept a bit further, and build the
antenna for 20 meters with no traps and then add a set wires for use on
30 meters, another set of wires for 40, and yet another set for 80.
clip on the wires for whichever band you want to operate.

That is my nickel's worth.

73,
Don W3FPR

On 5/13/2011 1:31 PM, AB5N wrote:

> Hi Guys-
>
> Well, I'm in week two of enjoyment with my new KX-1. I did have a few
> problems in assembling, but
> that is history.
>
> This little rig has a simple receiver which has only half the sensitivity of
> a usual radio. As well, we are dealing
> with 3-4 watts TX out max. We have to have an excellent antenna. I've tried
> the suggested 25 ft. long wire
> with radials. Ah, it's not good enough. I even got some strange RX-feedback
> internally at some frequencies using it. I believe the criteria for an
> excellent antenna will be as follows:
>
> 1. Will match up well using the internal tuner on all four bands.
>
> 2. Has enough metal in the air to provide adequate microvolts to the RX - to
> make it function well without
> being overloaded.
>
> 3. Provides some gain - or at least a clean predictable pattern
>
> 4. Is light, compact and easy to deploy.
>
> My inkling is that a normal Carolina Windom may be the thing. I'll work on
> developing a micro-QRP version.
>
> What doesn't work?
>
> Classic G5RV (102 Ft) - will not load on any band with tuner.
> Offset-Zepp fed with Coax (75'x25')
>
> What say guys? Anybody have superb luck with an antenna yet?
>
> Bob-AB5N
>

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Chip Stratton

Re: We need to develop the Ideal Antenna!

I've had seemingly good results with my KX1 on 20, 30, and 40 just using the
25 ft wire thrown into a tree and a 16 ft counterpoise along the ground. The
KXAT1 found useable matches every time. It seems like I remember doing OK on
80 meters too, but that may have been into my 6BTV vertical at home.

If I'm out during the day and happy with 20 meters only, I use an End-Fedz
20 meter half wave antenna and no counterpoise, and it works well for me
with the KXAT1 turned off.

Good luck!

Chip

On Fri, May 13, 2011 at 1:17 PM, Don Wilhelm <[hidden email]> wrote:

> Bob,
>
> Actually, a properly functioning KX1 has an MDS of better than -130 dBm,
> so it actually is a sensitive receiver.
>
> Some like the Carolina Windom, but I don't like any unbalanced antennas,
> and have a high preference for center fed antennas, they are easier to
> tame, and if the feedline leaves the antenna at right angles from the
> center, seldom do "RF-in-the-shack" problems emerge.
>
> The KXAT1 has a more limited range on 80 meters than the other bands
> just because the total inductance and capacitance is limited - only 3
> choices of each.
>
> I would suggest a trap antenna with traps for 40 and 20 meters. Feed it
> with balanced feedline cut a half wavelength (or multiple) on 80 meters
> - the tuner should be able to match it on 30 meters and the half
> wavelength of feedline on 80 meters should present a feedpoint impedance
> close to that at the antenna center (50 to 75 ohms) for 80, 40, and 20
> (assuming the traps are used).
> I have not actually built such an antenna, but the theory says it should
> work just fine. Keep the balanced feedline supported along its entire
> length and don't forget that there is a velocity factor to consider when
> determining a half wavelength - if you cannot do that, add a trap for 30
> meters and feed it with any length of coax. Coaxial traps are not
> difficult to build, and for QRP use, can even use RG174 on a piece of
> 1/2 inch PVC for a form. Doug DeMaw (SK) W1FB had information on
> building traps like that in QST a very long time ago (try in the
> 1980s). Also see the W1FB Antenna Notebook and/or the article in QST
> for Decenber 1984 page 37 by N4UU. Gary o'Neil N3GO also has some good
> information about coaxial traps on the web (use Google).
>
> I realize that a 135 foot long antenna is not "easy to deploy", so I
> would suggest an alternative - build a coax fed trap antenna for 40, 30
> and 20 meters (traps for 30 and 20), and carry along 2 33 foot lengths
> of wire - insulators on one end and an alligator clip on the other -
> when you want to operate 80 meters, add the wires to each end of the
> radiator. You could carry that concept a bit further, and build the
> antenna for 20 meters with no traps and then add a set wires for use on
> 30 meters, another set of wires for 40, and yet another set for 80.
> clip on the wires for whichever band you want to operate.
>
> That is my nickel's worth.
>
> 73,
> Don W3FPR
>
> On 5/13/2011 1:31 PM, AB5N wrote:
> > Hi Guys-
> >
> > Well, I'm in week two of enjoyment with my new KX-1. I did have a few
> > problems in assembling, but
> > that is history.
> >
> > This little rig has a simple receiver which has only half the sensitivity
> of
> > a usual radio. As well, we are dealing
> > with 3-4 watts TX out max. We have to have an excellent antenna. I've
> tried
> > the suggested 25 ft. long wire
> > with radials. Ah, it's not good enough. I even got some strange
> RX-feedback
> > internally at some frequencies using it. I believe the criteria for an
> > excellent antenna will be as follows:
> >
> > 1. Will match up well using the internal tuner on all four bands.
> >
> > 2. Has enough metal in the air to provide adequate microvolts to the RX -
> to
> > make it function well without
> > being overloaded.
> >
> > 3. Provides some gain - or at least a clean predictable pattern
> >
> > 4. Is light, compact and easy to deploy.
> >
> > My inkling is that a normal Carolina Windom may be the thing. I'll work
> on
> > developing a micro-QRP version.
> >
> > What doesn't work?
> >
> > Classic G5RV (102 Ft) - will not load on any band with tuner.
> > Offset-Zepp fed with Coax (75'x25')
> >
> > What say guys? Anybody have superb luck with an antenna yet?
> >
> > Bob-AB5N
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

AB5N

Re: We need to develop the Ideal Antenna!

In reply to this post by AB5N

Wow Guys, thanks!

It's great.. although this is my 5th sunspot cycle on the air, I am still challenged with
projects like this- which I can use help with. Thanks for all the ideas!

I guess I have come to the conclusion that nobody has really run the gamut trying antenna
designs for the KX-1. It's requirements are unique (the tuner etc). I'm a folded-dipole fan...
and use a Carolina Windom for my main general Hf antenna with great success.

OK, I'll "run the gamut"... with my goal being to fulfill the above criteria. I'll take into considerations
all the suggestions above as well. Traps may be involved... and clip-on elements.

The downside of the 25 ft wire and counterpoise is that you pick up lots of internal processor
noise from the KX-1. It is also just such a compromise.

As far as if my KX-1 is actually receiving correctly.. who knows? It's sensitivity is adequate, but it
is pretty deaf compared to say my FT-817. Because of the low noise floor, with any signal you have a chance of working with 4 watts -can be heard.

Back to the bench!

Bob-AB5N

Albers

KX-1 Ideal Antenna

In reply to this post by Mike Morrow-3

Well, lots of suggestions for trap dipoles, multiple insulators with jumpers, etc etc.

But I get excellent results with my simple antenna. I posted about this 4 or 5 years ago. I went to Radio Shack and bought a 50 ft roll of loudspeaker wire. I un-zipped it. Turns out actual length of each leg is 51 ft 8 in, but I doubt the length is critical. One leg goes as high in the air as I can get it with available supports. Sloper or inverted L or whatever. Other leg lies on the ground. Direction doesn't seem to matter. ATU loads it just fine on all three bands and has given me many nice QSOs including some trans-continental and transatlantic.

73
Ray K2HYD
KX-1 #608

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K7TV

KX1 - We need to develop the ideal antenna

After using a 26 ft wire with counterpoise as well as vertical and
horizontal Buddipole configurations, for the past year or so I have settled
on a dipole with jumpers, and this is the best configuration yet. KK5F beat
me to suggesting it here, but I am chiming in because the subject is
interesting, and details are worth discussing. Here are some details of
mine:

1. My insulators are rectangular pieces of Lexan sheet, cut to about
0.25" x 0.5" x 1.75". Each insulator has a row of 6 holes. The holes are
just wide enough to pass the male and female connectors, which are Molex
pins with added shrink-wrap tubing to avoid wire breakage. The wire from
each side is passed through 3 holes in a zig-zag fashion, and the connectors
are joined hanging in the air, forming a loop of about 1.5" diameter. This
arrangement is easy to disassemble in the field, yet holds the wire securely
without placing stress on the connection itself. It depends on the friction
created between the shoulders of the holes and the wire insulation. The
ability to disassemble without tools helps me when I want to remove the 80 m
sections, or make repairs or replacements.

2. The wire I use is the extremely lightweight copperclad available
from The Wireman, which is strong and has a tough insulation which is happy
to be subjected to the sharp edges of the insulator. It is also stiffer than
some other kinds of wire. I find that the insulators hold securely even with
softer wire, and I don't expect regular pvc insulation to be a problem, as I
never put much mechanical tension on the wire. I do think the copperclad is
more efficient than tinned copper which should have more rf resistance.
Don't know how large this effect is in practice, but every little bit helps
with qrp.

3. My feedline is RG-58 from my Buddipole, which includes a
lightweight balun using beads. This can be purchased as a separate item.

4. The configuration is inverted-vee, supported at up to 22 ft or so.
At the bottom is the tripod plus short mast from the Buddipole, which is
light enough to be carried in the field for shorter trips. This is from a
few years ago. I understand that Buddipole currently only makes a heavier
model tripod that is intended to support a small beam. In any case, my
tripod is the heaviest part of the setup, and for a longer trip on foot I
would leave it at home and use whatever I can find to support the pole. The
tripod with Buddipole short mast provides about 8 of the 22 ft. The rest of
the height comes from a Cabela's Crappie Pole which is quite a bargain at
$20 or so, and extremely light. If I remember right it is a 16 ft model, but
with the top section removed. (It will remove itself the first time the
antenna falls over!). I had to make a custom piece to connect the crappie
pole to the Buddipole mast.

5. I store the antenna with feedline detached on two "Halo Winder"
type spools designed for kite string. I don't remember which vendor I bought
them from, but they were available in a variety of sizes, without string,
easy to find on the net. I use the 5" diameter model which leaves room to
spare with wire for all bands including 80 m. Each spool with wire and
insulators weighs about 5 oz. My center insulator is similar to the other
insulators, and I detach the wire by unthreading the 3 holes on each side
for transportation. A hole in the middle slips right over the crappie pole,
and stops because the pole sections are conical. At first I used Buddipole's
mini banana connections for the feedline, but the plugs were damaged when
the antenna fell, so now the feedline is soldered and bolted to the
insulator, with pigtails for Molex pin connection to the antenna wire. (I
got a new feedline from Buddipole, since I still like to use the complete
Buddipole in some situations where weight is not an issue.)

Before I took this antenna into the field, I tried flexing the soldered
copperclad to see if it would break. It would not. The steel core seemed
very hard to break. Then, first time in the field, the KX1 ATU wouldn't find
a good match, and it turned out the wire had broken right at a solder joint.
That's when I slightly enlarged the insulator holes and added shrinkwrap
tubing around the solder joints. It turned out that the wire still locked
very securely in the holes.

The Molex pins tend to get loose with use. Not a big deal, as they can
easily be adjusted in the field with a knife and maybe a rock. Nevertheless,
I still want to find better pins. I dream about gold-plated machined pins
such as those found in some expensive military connectors or maybe top
quality IC connectors/chip carriers. The ideal solution would include both
the female and male parts, available without cannibalizing a multipin
connector; the overall diameter should be small (1/8" or less) to slip
through insulator holes, and the the pair should have enough spring
force/friction to stick together when used without a connector shell. Anyone
know a source?

I have long toyed with the idea of trying traps, especially for the 20/30
switch point, where the trap should be very light and not have all that much
reactance to influence the bandwidth at, say, 80.

Overall I like this antenna so much that I have toyed with the idea of
making them for sale. Just kidding.

73,

Erik K7TV

KK5F wrote:

The approach that I found worked best for me was an antenna that was a
full-length 40m dipole (66 feet), with each leg broken in six places with a
home-made PCV tubing insulator with integral jumper and clip so that the
appropriate length dipole can be established for all seven HF bands between
10m and 40m. I built the antenna for all these bands for use with any rig,
not just the limited coverage of a K1 or KX1. It works better than any
other antenna I've ever used in a field environment. It typically takes
less than a minute to alter insulator jumper configuration to switch to
another band. It meets *all* of the desired criteria listed by Bob, to
which I would add "5. Is very inexpensive and quick to home-brew." (I have
a pdf file with construction details, diagrams, and photos that I'll e-mail
to anyone on request.) I use the technique that you suggest of attaching a
33-foot segment to each leg for 80m operation, which is rare for me.

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David Cutter

Re: KX1 - We need to develop the ideal antenna

This is what we used to call the "shirt button antenna" 'cos we used shirt
buttons as the insulators which saves and awful lot of work making them.
For light weight I would consider 300ohm ribbon for the feeder and a simple
choke/balun to the connector. Crock clips rust in our wx and slide switches
eventually pack up, so, I'm thinking of bullet connectors next.
73
David
G3UNA

On 15 May 2011 04:40, Erik Basilier <[hidden email]> wrote:

> After using a 26 ft wire with counterpoise as well as vertical and
> horizontal Buddipole configurations, for the past year or so I have settled
> on a dipole with jumpers, and this is the best configuration yet. KK5F
> beat
> me to suggesting it here, but I am chiming in because the subject is
> interesting, and details are worth discussing. Here are some details of
> mine:
>
>
>
> 1. My insulators are rectangular pieces of Lexan sheet, cut to about
> 0.25" x 0.5" x 1.75". Each insulator has a row of 6 holes. The holes are
> just wide enough to pass the male and female connectors, which are Molex
> pins with added shrink-wrap tubing to avoid wire breakage. The wire from
> each side is passed through 3 holes in a zig-zag fashion, and the
> connectors
> are joined hanging in the air, forming a loop of about 1.5" diameter. This
> arrangement is easy to disassemble in the field, yet holds the wire
> securely
> without placing stress on the connection itself. It depends on the friction
> created between the shoulders of the holes and the wire insulation. The
> ability to disassemble without tools helps me when I want to remove the 80
> m
> sections, or make repairs or replacements.
>
> 2. The wire I use is the extremely lightweight copperclad available
> from The Wireman, which is strong and has a tough insulation which is happy
> to be subjected to the sharp edges of the insulator. It is also stiffer
> than
> some other kinds of wire. I find that the insulators hold securely even
> with
> softer wire, and I don't expect regular pvc insulation to be a problem, as
> I
> never put much mechanical tension on the wire. I do think the copperclad is
> more efficient than tinned copper which should have more rf resistance.
> Don't know how large this effect is in practice, but every little bit helps
> with qrp.
>
> 3. My feedline is RG-58 from my Buddipole, which includes a
> lightweight balun using beads. This can be purchased as a separate item.
>
> 4. The configuration is inverted-vee, supported at up to 22 ft or so.
> At the bottom is the tripod plus short mast from the Buddipole, which is
> light enough to be carried in the field for shorter trips. This is from a
> few years ago. I understand that Buddipole currently only makes a heavier
> model tripod that is intended to support a small beam. In any case, my
> tripod is the heaviest part of the setup, and for a longer trip on foot I
> would leave it at home and use whatever I can find to support the pole. The
> tripod with Buddipole short mast provides about 8 of the 22 ft. The rest of
> the height comes from a Cabela's Crappie Pole which is quite a bargain at
> $20 or so, and extremely light. If I remember right it is a 16 ft model,
> but
> with the top section removed. (It will remove itself the first time the
> antenna falls over!). I had to make a custom piece to connect the crappie
> pole to the Buddipole mast.
>
> 5. I store the antenna with feedline detached on two "Halo Winder"
> type spools designed for kite string. I don't remember which vendor I
> bought
> them from, but they were available in a variety of sizes, without string,
> easy to find on the net. I use the 5" diameter model which leaves room to
> spare with wire for all bands including 80 m. Each spool with wire and
> insulators weighs about 5 oz. My center insulator is similar to the other
> insulators, and I detach the wire by unthreading the 3 holes on each side
> for transportation. A hole in the middle slips right over the crappie pole,
> and stops because the pole sections are conical. At first I used
> Buddipole's
> mini banana connections for the feedline, but the plugs were damaged when
> the antenna fell, so now the feedline is soldered and bolted to the
> insulator, with pigtails for Molex pin connection to the antenna wire. (I
> got a new feedline from Buddipole, since I still like to use the complete
> Buddipole in some situations where weight is not an issue.)
>
>
>
> Before I took this antenna into the field, I tried flexing the soldered
> copperclad to see if it would break. It would not. The steel core seemed
> very hard to break. Then, first time in the field, the KX1 ATU wouldn't
> find
> a good match, and it turned out the wire had broken right at a solder
> joint.
> That's when I slightly enlarged the insulator holes and added shrinkwrap
> tubing around the solder joints. It turned out that the wire still locked
> very securely in the holes.
>
>
>
> The Molex pins tend to get loose with use. Not a big deal, as they can
> easily be adjusted in the field with a knife and maybe a rock.
> Nevertheless,
> I still want to find better pins. I dream about gold-plated machined pins
> such as those found in some expensive military connectors or maybe top
> quality IC connectors/chip carriers. The ideal solution would include both
> the female and male parts, available without cannibalizing a multipin
> connector; the overall diameter should be small (1/8" or less) to slip
> through insulator holes, and the the pair should have enough spring
> force/friction to stick together when used without a connector shell.
> Anyone
> know a source?
>
>
>
> I have long toyed with the idea of trying traps, especially for the 20/30
> switch point, where the trap should be very light and not have all that
> much
> reactance to influence the bandwidth at, say, 80.
>
>
>
> Overall I like this antenna so much that I have toyed with the idea of
> making them for sale. Just kidding.
>
>
>
> 73,
>
> Erik K7TV
>
>
>
>
>
> KK5F wrote:
>
>
>
> The approach that I found worked best for me was an antenna that was a
> full-length 40m dipole (66 feet), with each leg broken in six places with a
> home-made PCV tubing insulator with integral jumper and clip so that the
> appropriate length dipole can be established for all seven HF bands between
> 10m and 40m. I built the antenna for all these bands for use with any rig,
> not just the limited coverage of a K1 or KX1. It works better than any
> other antenna I've ever used in a field environment. It typically takes
> less than a minute to alter insulator jumper configuration to switch to
> another band. It meets *all* of the desired criteria listed by Bob, to
> which I would add "5. Is very inexpensive and quick to home-brew." (I
> have
> a pdf file with construction details, diagrams, and photos that I'll e-mail
> to anyone on request.) I use the technique that you suggest of attaching a
> 33-foot segment to each leg for 80m operation, which is rare for me.
>
>
>
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Geoffrey Mackenzie-Kennedy

Re: We need to develop the Ideal Antenna!

In reply to this post by AB5N

Bob,

An interesting idea for a multiband centre-fed antenna was described by
W4JRW in the December 1960 issue of QST, "Multiband Antennas using
Decoupling Stubs".

The decoupling stubs that he used are not hung at right angles to the
antenna wire, but are "horizontal" stubs which results in a tidy
arrangement. In fact one of the antennas he described uses a length of
tubular Twin-Lead, one conductor forming the antenna and the second
conductor cut and removed in places to make the decoupling stubs, which
results in a light weight antenna easy to carry.

73,

Geoff
GM4ESD

On Saturday, May 14, 2011 11:13 PM, "AB5N" <[hidden email]> wrote:

> Wow Guys, thanks!
>
> It's great.. although this is my 5th sunspot cycle on the air, I am still
> challenged with
> projects like this- which I can use help with. Thanks for all the ideas!
>
> I guess I have come to the conclusion that nobody has really run the gamut
> trying antenna
> designs for the KX-1. It's requirements are unique (the tuner etc). I'm a
> folded-dipole fan...
> and use a Carolina Windom for my main general Hf antenna with great
> success.
>
> OK, I'll "run the gamut"... with my goal being to fulfill the above
> criteria. I'll take into considerations
> all the suggestions above as well. Traps may be involved... and clip-on
> elements.
>
> The downside of the 25 ft wire and counterpoise is that you pick up lots
> of
> internal processor
> noise from the KX-1. It is also just such a compromise.
>
> As far as if my KX-1 is actually receiving correctly.. who knows? It's
> sensitivity is adequate, but it
> is pretty deaf compared to say my FT-817. Because of the low noise floor,
> with any signal you have a chance of working with 4 watts -can be heard.
>
> Back to the bench!
>
> Bob-AB5N

Michael Babineau-2

Re: Elecraft] KX-1 Ideal Antenna

In reply to this post by Mike Morrow-3

>Well, lots of suggestions for trap dipoles, multiple insulators with jumpers, etc etc.

>But I get excellent results with my simple antenna. I posted about this 4 or 5 years ago. I went to Radio Shack and bought a 50 ft roll of loudspeaker wire. I un-zipped it. Turns out actual length of each leg is >51 ft 8 in, but I doubt the length is critical. One leg goes as high in the air as I can get it with available supports. Sloper or inverted L or whatever. Other leg lies on the ground. Direction doesn't seem to matter. >ATU loads it just fine on all three bands and has given me many nice QSOs including some trans-continental and transatlantic.

>73
>Ray K2HYD
>KX-1 #608

I have also had pretty good luck with an end-fed 51 foot wire erected as an inverted-vee. I have worked this again 5 radials each 16 feet long
and it will match and work fine on 40m / 30m /20m with my KX1 internal tuner. I don't have 80m in my KX1 so I can't comment on that band.

I also use a homebrew G5RV JR (51 feet) feed with 14 ft of TV twinlead attached to about 30 feet of RG-6 (with ten turns
of the coax wound on a 6" form to create a choke balun). I also sometimes use a "clip-lead" dipole for 40m/30m/20m or a 44 ft doublet (aka
Norcal doublet) and have had great luck with all of these.

It would be a challenge to find an antenna that will also match on 80m as the KX1 internal tuner is really not well suited for matching on 80m
due to its limited range of switched inductance.

If a 51 foot end-fed wire doesn't give a good match on 80m then one could add some additional inductance via a home-brew coil
inserted in series to help the tuner out. It also might worth trying a W3EDP or alternately an 86 foot end-fed wire worked against
some ground radials. This is a good length for multi-band operation as it is not a multiple of a half-wave on any amateur
HF band.

Michael VE3WMB

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Geoffrey Mackenzie-Kennedy

Re: KX1 - We need to develop the ideal antenna

In reply to this post by Mike Morrow-3

Sorry for a "me too" post, but I agree completely with Mike's comments about
Flexweave. I use the type which is enclosed in a clear UV resistant jacket
because there are many types of birds living here, buzzards, hawks and
smaller types, many of whom like to perch on my wire antennas, and the
jacket removes the possibility that the Flexweave's copper strands might be
damaged by their claws.

73,
Geoff
GM4ESD

On May 16, 2011 at 12:28 AM, Mike Morrow KK5F wrote:

> My dipole assembly has been in service for 15 years, but I have used many
> wire antennas in my experiments. The ***ONLY*** wire that I've ever used
> that NEVER failed anywhere or anyhow is Flexweave-tm, also available from
> Wireman (items 542 through 549) and other sources. It'll cost at least
> $.21/foot (100 feet or more), but it is worth several times that, IMHO.
> I use 14 ga. Flexweave, which consists of 168 fine strands that create a
> wire that is extrememly flexible, durable, and a real joy to work.
>

> Flexweave-tm will eliminate that possibility of failure. In fact, if some
> Flexweave-type of wire is not used, failure due to wire fatigue is a
> certainty...probably sooner than later...with such wire antennas.

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David Cutter

Re: KX1 - We need to develop the ideal antenna

I can understand this in a home situation, but for use with a very
lightweight, low bulk portable rig like a KX1 I would use something like
16/0.2, (16 strands of 0.2mm copper, similar to 14/0076). I wouldn't for
instance hang flexweave from a floppy fibreglass pole, but I've done it with
this thin multi-strand insulated wire. Flat twin loudspeaker wire as shown
in (all?) post-war ARRL handbooks doesn't even need a centre
insulator/connector. My criteria is: if it falls out of the
tree/balcony/hotel room window, will it cause damage or hurt someone?

73
David
G3UNA

On 16 May 2011 11:54, Geoffrey Mackenzie-Kennedy <[hidden email]>wrote:

> Sorry for a "me too" post, but I agree completely with Mike's comments
> about
> Flexweave. I use the type which is enclosed in a clear UV resistant jacket
> because there are many types of birds living here, buzzards, hawks and
> smaller types, many of whom like to perch on my wire antennas, and the
> jacket removes the possibility that the Flexweave's copper strands might be
> damaged by their claws.
>
> 73,
> Geoff
> GM4ESD
>
>
> On May 16, 2011 at 12:28 AM, Mike Morrow KK5F wrote:
>
> > My dipole assembly has been in service for 15 years, but I have used many
> > wire antennas in my experiments. The ***ONLY*** wire that I've ever used
> > that NEVER failed anywhere or anyhow is Flexweave-tm, also available from
> > Wireman (items 542 through 549) and other sources. It'll cost at least
> > $.21/foot (100 feet or more), but it is worth several times that, IMHO.
> > I use 14 ga. Flexweave, which consists of 168 fine strands that create a
> > wire that is extrememly flexible, durable, and a real joy to work.
> >
>
> > Flexweave-tm will eliminate that possibility of failure. In fact, if
> some
> > Flexweave-type of wire is not used, failure due to wire fatigue is a
> > certainty...probably sooner than later...with such wire antennas.
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>

Geoffrey Mackenzie-Kennedy

Re: KX1 - We need to develop the ideal antenna

David,

I take your point. Not sure about the use of twin loudspeaker wire for
portable applications. It might be satisfactory when split to make the
antenna element, but could be lossy when used as a feeder, don't know.

73,
Geoff
GM4ESD

On May 16, 2011 at 12:48 PM, CUTTER DAVID

> I can understand this in a home situation, but for use with a very
> lightweight, low bulk portable rig like a KX1 I would use something like
> 16/0.2, (16 strands of 0.2mm copper, similar to 14/0076). I >
> wouldn't for instance hang flexweave from a floppy fibreglass pole, but
> I've done it with this thin multi-strand insulated wire. Flat twin
> loudspeaker wire as shown in (all?) post-war ARRL handbooks >
> doesn't even need a centre insulator/connector. My criteria is: if it
> falls out of the tree/balcony/hotel room window, will it cause damage or
> hurt someone?

73
David
G3UNA

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AC7AC

Re: KX1 - We need to develop the ideal antenna

CONTENTS DELETED

The author has deleted this message.

Vic K2VCO

Re: KX1 - We need to develop the ideal antenna

There was an article in QST a few years back in which a guy actually measured losses in
various kinds of zip cord. Losses were very high -- his conclusion was "don't use this
stuff for feedline except in emergencies."

On 5/16/2011 8:38 AM, Ron D'Eau Claire wrote:

> The feed line losses go up as the impedance goes down. "Zip" cord (like
> speaker wire) has two close spaced conductors, so the impedance is quite low
> as "balanced" feed lines go. I've seen actual impedance measurements in the
> 50 to 100 ohm range published.
>
> So it might be a little better than coax at high SWR's but not
> significantly.
>
> Ron AC7AC
>
> -----Original Message-----
>
> David,
>
> I take your point. Not sure about the use of twin loudspeaker wire for
> portable applications. It might be satisfactory when split to make the
> antenna element, but could be lossy when used as a feeder, don't know.
>
> 73,
> Geoff
> GM4ESD
>
> On May 16, 2011 at 12:48 PM, CUTTER DAVID
>
>> I can understand this in a home situation, but for use with a very
>> lightweight, low bulk portable rig like a KX1 I would use something like
>> 16/0.2, (16 strands of 0.2mm copper, similar to 14/0076). I>
>> wouldn't for instance hang flexweave from a floppy fibreglass pole, but
>> I've done it with this thin multi-strand insulated wire. Flat twin
>> loudspeaker wire as shown in (all?) post-war ARRL handbooks>
>> doesn't even need a centre insulator/connector. My criteria is: if it
>> falls out of the tree/balcony/hotel room window, will it cause damage or
>> hurt someone?
>
> 73
> David
> G3UNA

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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daleputnam

Re: KX1 - We need to develop the ideal antenna

Zip cord, at 50 - 72 ohm or so impedance, is a whole lot closer to the center fed impedance of a "close to the ground" dipole.
Makes a fair amount of sense, to use it for feedline, clear down to the rig, when the rig has a balanced output.. or to the balanced to unbalanced, 1 to 1 ratio apparatus. And with a stranded, larger than RG-58 or RG-59 coax center, it won't have any additional I-R loss than that coax, and our HF freq. And of course, making the distinction that we are talking about a single band dipole... not a multiband, center fed with what ever the tx is dialed to balanced antenna.

--... ...-- Dale - WC7S in Wy

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Jack Smith-6

Re: KX1 - We need to develop the ideal antenna

10 years ago, I measured the loss of zip cord, with the results below.
The measured results are based on a 17 ft length of zip cord.

Frequency Measured Loss (dB) Loss (dB)/100 ft
5 0.4 2.3
10 0.6 3.5
15 0.8 4.6
20 0.95 5.5
25 1.2 6.9
30 1.4 8.1

For comparison, RG-58 is spec'd at 1.4 dB/100 ft at 10 MHz and RG-178 at
3.3 dB/100 ft. So, zip cord is about as good (or bad) as RG-174 at 10 MHz.

I've significantly improved my measurement ability since then and should
revisit the subject.

Jack K8ZOA

On 5/16/2011 12:02 PM, Dale Putnam wrote:

> Zip cord, at 50 - 72 ohm or so impedance, is a whole lot closer to the center fed impedance of a "close to the ground" dipole.
> Makes a fair amount of sense, to use it for feedline, clear down to the rig, when the rig has a balanced output.. or to the balanced to unbalanced, 1 to 1 ratio apparatus. And with a stranded, larger than RG-58 or RG-59 coax center, it won't have any additional I-R loss than that coax, and our HF freq. And of course, making the distinction that we are talking about a single band dipole... not a multiband, center fed with what ever the tx is dialed to balanced antenna.
>
> --... ...-- Dale - WC7S in Wy
>
>
> ______________________________________________________________
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Stephen G4SJP

Re: KX1 - We need to develop the ideal antenna

I have made no measurements, but experience gained from zip cord
bought from Wal-Mart, left me with the conclusion that it indeed was
pretty poor. Thanks for the confirmation of why I had no QSOs from
Idaho!

73 Stephen G4SJP

On 16 May 2011 17:51, Jack Smith <[hidden email]> wrote:

> 10 years ago, I measured the loss of zip cord, with the results below.
> The measured results are based on a 17 ft length of zip cord.
>
> Frequency Measured Loss (dB) Loss (dB)/100 ft
> 5 0.4 2.3
> 10 0.6 3.5
> 15 0.8 4.6
> 20 0.95 5.5
> 25 1.2 6.9
> 30 1.4 8.1
>
>
> For comparison, RG-58 is spec'd at 1.4 dB/100 ft at 10 MHz and RG-178 at
> 3.3 dB/100 ft. So, zip cord is about as good (or bad) as RG-174 at 10 MHz.
>
> I've significantly improved my measurement ability since then and should
> revisit the subject.
>
> Jack K8ZOA
>
>
>
> On 5/16/2011 12:02 PM, Dale Putnam wrote:
>> Zip cord, at 50 - 72 ohm or so impedance, is a whole lot closer to the center fed impedance of a "close to the ground" dipole.
>> Makes a fair amount of sense, to use it for feedline, clear down to the rig, when the rig has a balanced output.. or to the balanced to unbalanced, 1 to 1 ratio apparatus. And with a stranded, larger than RG-58 or RG-59 coax center, it won't have any additional I-R loss than that coax, and our HF freq. And of course, making the distinction that we are talking about a single band dipole... not a multiband, center fed with what ever the tx is dialed to balanced antenna.
>>
>> --... ...-- Dale - WC7S in Wy
>>
>>
>> ______________________________________________________________
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Geoffrey Mackenzie-Kennedy

Re: KX1 - We need to develop the ideal antenna

In reply to this post by daleputnam

Hi Dale,

K1TD made some measurements back in 1979 on a transmission line made from
dry Zip Cord, and reported that its nominal characteristic impedance at HF
was 105 ohms and its velocity factor was 0.69.

He also measured the loss per 100ft at various frequencies when the line was
terminated by a 105 ohm load (105 +j0).

F MHz Loss db per 100ft

3.5 0.7
7.0 1.8
14.1 4.0
28.1 7.5

Maybe modern ZIP Cord is different, but I hope that this helps.

73,
Geoff
GM4ESD

On Monday, May 16, 2011 at 5:02 PM, Dale Putnam WC7S wrote:

> Zip cord, at 50 - 72 ohm or so impedance, is a whole lot closer to the
center fed impedance of a "close to the ground" dipole.
> Makes a fair amount of sense, to use it for feedline, clear down to the
> rig, when the rig has a balanced output.. or to the balanced to
> unbalanced, 1 to 1 ratio apparatus. And with a stranded, larger than RG-58
> or RG-59 coax center, it won't have any additional I-R loss than that
> coax, and our HF freq. And of course, making the distinction that we are
> talking about a single band dipole... not a multiband, center fed with
> what ever the tx is dialed to balanced antenna.
>
> --... ...-- Dale - WC7S in Wy

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