Re: AX1 - Collapsible Whips
The DS1 has apparently been replaced by the CLV,
which is now center loaded instead of base loaded.? The CLV is
half the cost of the AX1 but requires quite a bit of user
assembly.? It folds up very small (12 inches) but is considerably
larger than the DS1 (or AX1) when set up ... and according to QRP
Guys ... considerably more efficient, which is why they switched
to it. ??
Dave?? AB7E
On 3/26/2025 3:04 PM, John KK4ITX via
groups.io wrote:
toggle quoted message
Show quoted text
Back in December I ran a test of QRPGUYS DS1, similar to the AX1
and a QRPLABS U4B 27mW transmitter on WSPR. ?I ran the test for a
complete 24 hour cycle. ?The antenna was mounted on a tripod about
18” ago. Counterpoise was 16ft. ?SWR about 1.2:1.
The map below shows the results. Was the counterpoise the
radiator, I do not know but the results are what I was looking
for however they developed. 
We can all discuss the best, most effective and so on but this
picture is worth a bunch of words. The picture below shows the antenna setup, West is through
the building (all aluminum) that’s less than 15 ft away.
It’s my go to antenna for
parks, beaches and most other operations.
John
KK4ITX?
Visit: ?.
? ?
It must be stainless steel because I
have left it outside in the rain many times and there is
no rust.
?
Paul
?
?
Paul is
that 25 footer stainless steel?
de KB9BVN
Brian
On 3/26/2025 12:47 PM, Paul Quillen
N4LCD via wrote:
Chameleon also has a 25’ extendable
whip for $100.
Also available at DX Engineering
with free shipping due to price.
Very well built.
?
?
?
The Chameleon whips are built
pretty well at the bottom. The early MFJ whips were
quite fragile, but the later ones were much better.
The Chameleons are still built better than the MFJ
items..............
73 de Lee KX4TT
On
Tuesday, March 25, 2025 at 06:39:40 PM EDT,
MIKE N6ZW via <n6zw@...>
wrote:
Those
are the same that MFJ used to sell
before they went closed their doors. I
use one for several HB antennas and it
works very well alone. You can even base
load one easily.? 73,? Mike n6zw
On
03/25/2025 3:28 PM PDT Dave AB7E via
<ab7echo@...>
wrote:
I
forgot to include the link to the SS17
whip:
The pictures in the first review are
mine (Alice is my wife's name).
Dave? AB7E
-------- Forwarded Message --------
Except
that the AX1 isn't enough of a
vertical to actually act like a short
vertical.? If you model an AX1 and
look at the current distribution you
will see that most of it is in the
counterpoise wire.? To be honest, the
AX1 whip is mostly a convenient lossy
tank circuit to act as a counterpoise
for the counterpoise wire ... or in
some case, the shield of the coax
feedline.
I know how to use EZNEC.? I've used it
continually since 1993 or so when it
was still called ELNEC, and I'm
actually a big fan of vertical
antennas for portable operation.? My
choice, though, is the Chameleon SS17
collapsible whip with elevated
radials.? My version weighs about 3.5
pounds ... with steel stakes ... and I
can set it up in less than ten
minutes.
An an end fed wire doesn't have to be
very far off the ground to avoid being
a worm warmer.? Why do you think
elevated radials work when they are
only a foot or two off the ground???
I'm not actually a big fan of end fed
wire antennas, but for portable use I
don't think they can be beat for
performance, size, weight, or cost.? I
wish I had an AX1 to compare against
various alternatives using WSPR, but
I'm not willing to spend the money on
one just to prove ... or disprove, if
that should be the case ... my point.?
Curiously, almost nobody who owns an
AX1 has bothered to do a similarly
rigorous A-vs-B comparison either.?
Presumably, like you, they don't
really care as long as "it works".
Dave?? AB7E
On
3/25/2025 2:44 PM, Dan N7CQR via
wrote:
I’ve
used this strategy on bare summits
above 3-4000 feet with some success.
Unfortunately at sea level or low
elevation you’re just warming the
earthworms. Any type of short
vertical with an elevated radial
will provide a decent takeoff angle.
You can model this in EZNEC. A good
resource for using short verticals
effectively are the writings of
Jerry Severns for the ARRL Antenna
handbook or the website for antenna
‘guru’ LB Cebik.?
You
should try the EFRW sometime
just laying on the ground, or
maybe laying across a rock.?
I'll say again ... most of the
radiating from an AX1 comes from
either the counterpoise or the
shield of the coax (if not using
a common mode choke), and for
the majority of uses either of
those are lying on or very near
the top of the ground.? The
surface of most "ground" isn't
an RF ground, and if the soil is
dry or fairly non-conductive the
actual RF ground is probably
several feet below the surface.?
Not sure what the ground
characteristic in the Orkneys
is, though.
Dave??
AB7E
On
3/25/2025 12:18 PM, Dan N7CQR
via
wrote:
I
forgot to mention that I also
carry a EFRW in my little
bag,that of course is more
efficient than almost short
loaded vertical. Mine is
Adam’s K6ARK clever design
that incorporates a 9:1 balun
into the BNC connector. But
you have to have either a tree
or a pole to toss it into. If
you’ve been to the Orkneys you
know that there’s not many
trees there…?
On
Mar 25, 2025, at 11:22,
Dan N7CQR via
<N7CQR@...>
wrote:
It’s
a matter of trade offs
that each operator is
willing to make. No doubt
that other larger antennas
can be more efficient,but
how much are you willing
to pack around? Last
summer I made a trip to
the Orkney Islands,and you
are definitely limited in
how much baggage you can
bring on a very small
plane. . Wanting to get
some radio time in,it’s an
easy decision to bring my
small bag and still have
room for clothing and
other essentials. And I
successfully got on the
air with the AX1 at 5W.
Worked 10 countries in one
45 minute session. For me
that’s a good trade off.
?Back home I use the best
antenna I can reasonably
carry. Lately I’ve been
using the Chelegance MC
750 vertical which is a
full 1/4 wave on 20-10
Meters with the KH1 and
having excellent results.
It breaks down into a
relatively small
package-but still nothing
I’d ever fly or take a
longer hike with. We have
so many great options
these days.?
?
--
72 de KB9BVN
|
Re: AX1 - Collapsible Whips
Yes, definitely.? I? modeled my attempt at an AX1
with 10 feet of the counterpoise about one foot off the ground,
and 3 feet of it angled upward to the base of the whip at 4 feet
off the ground.? I tried to approximately simulate a typical use
... either somebody holding the AX1 while standing or having it
mounted on a picnic table.
Dave?? AB7E
On 3/26/2025 2:53 PM, Brian KB9BVN via
groups.io wrote:
toggle quoted message
Show quoted text
I know when I deploy my AX1/KX2 with an elevated radial or
three...it seems to work a lot better than laying the radials on
the ground.
When I can find something to drape them over.
de KB9BVN
Brian
On 3/26/2025 5:10 PM, Dave AB7E via
groups.io wrote:
The stainless steel used in extendable whip antennas is
typically type 301 or 304, both of which have a relative
permeability of 1.05 or less ... which means they are
essentially non-magnetic and don't have much more skin effect
than copper or aluminum.? I just used EZNEC Pro v7 with NEC5
(which does model skin effect) to model a full size ground plane
antenna for 20m using 3/8 inch diameter tubing (similar to the
17 foot extendable whips) and the difference in performance
between stainless steel and copper taking into account the
difference in both resistivity and permeability is about 0.16
dB.? Even if the entire 17 foot whip was only 0.1 inches in
diameter the difference is only 0.4 dB.
So no ... it is not a big deal.? The additional loss is
negligible.? The loss in any of these short base loaded
alternatives is FAR greater.
By the way, I also generated a model as close to what I think an
AX1 looks like as I could get.? With a 13 foot counterpoise wire
EZNEC said there is 16 times (!!) more radiated power from the
counterpoise wire than there is from the 4 foot whip.
Dave?? AB7E
On 3/26/2025 6:50 AM, kb1gmx via
groups.io wrote:
?
Generally not a fan of stainless whips, the stainless is
strong but has
high resistance and losses at RF.? Depite that, they are
handy and I
have a few good ones from Buddypole.
?
--
Allison
--------------------------
Please, private email goes to bit bucket
--
72 de KB9BVN
|
Re: AX1 - Collapsible Whips
Back in December I ran a test of QRPGUYS DS1, similar to the AX1 and a QRPLABS U4B 27mW transmitter on WSPR. ?I ran the test for a complete 24 hour cycle. ?The antenna was mounted on a tripod about 18” ago. Counterpoise was 16ft. ?SWR about 1.2:1.
The map below shows the results. Was the counterpoise the radiator, I do not know but the results are what I was looking for however they developed.  We can all discuss the best, most effective and so on but this picture is worth a bunch of words. The picture below shows the antenna setup, West is through the building (all aluminum) that’s less than 15 ft away. 
It’s my go to antenna for parks, beaches and most other operations.
John KK4ITX?
Visit: ?. ? ?
toggle quoted message
Show quoted text
On Mar 26, 2025, at 16:28, Paul Quillen N4LCD via < daytradingcourse@...> wrote: It must be stainless steel because I have left it outside in the rain many times and there is no rust. ? Paul ? ? Paul is that 25 footer stainless steel?
de KB9BVN
Brian
On 3/26/2025 12:47 PM, Paul Quillen N4LCD via wrote: Chameleon also has a 25’ extendable whip for $100. Also available at DX Engineering with free shipping due to price. Very well built. ? ? ? The Chameleon whips are built pretty well at the bottom. The early MFJ whips were quite fragile, but the later ones were much better. The Chameleons are still built better than the MFJ items..............
73 de Lee KX4TT On Tuesday, March 25, 2025 at 06:39:40 PM EDT, MIKE N6ZW via <n6zw@...> wrote: Those are the same that MFJ used to sell before they went closed their doors. I use one for several HB antennas and it works very well alone. You can even base load one easily.? 73,? Mike n6zw On 03/25/2025 3:28 PM PDT Dave AB7E via <ab7echo@...> wrote:
I forgot to include the link to the SS17 whip:
The pictures in the first review are mine (Alice is my wife's name).
Dave? AB7E
-------- Forwarded Message --------
Except that the AX1 isn't enough of a vertical to actually act like a short vertical.? If you model an AX1 and look at the current distribution you will see that most of it is in the counterpoise wire.? To be honest, the AX1 whip is mostly a convenient lossy tank circuit to act as a counterpoise for the counterpoise wire ... or in some case, the shield of the coax feedline.
I know how to use EZNEC.? I've used it continually since 1993 or so when it was still called ELNEC, and I'm actually a big fan of vertical antennas for portable operation.? My choice, though, is the Chameleon SS17 collapsible whip with elevated radials.? My version weighs about 3.5 pounds ... with steel stakes ... and I can set it up in less than ten minutes.
An an end fed wire doesn't have to be very far off the ground to avoid being a worm warmer.? Why do you think elevated radials work when they are only a foot or two off the ground??? I'm not actually a big fan of end fed wire antennas, but for portable use I don't think they can be beat for performance, size, weight, or cost.? I wish I had an AX1 to compare against various alternatives using WSPR, but I'm not willing to spend the money on one just to prove ... or disprove, if that should be the case ... my point.? Curiously, almost nobody who owns an AX1 has bothered to do a similarly rigorous A-vs-B comparison either.? Presumably, like you, they don't really care as long as "it works".
Dave?? AB7E
On 3/25/2025 2:44 PM, Dan N7CQR via wrote: I’ve used this strategy on bare summits above 3-4000 feet with some success. Unfortunately at sea level or low elevation you’re just warming the earthworms. Any type of short vertical with an elevated radial will provide a decent takeoff angle. You can model this in EZNEC. A good resource for using short verticals effectively are the writings of Jerry Severns for the ARRL Antenna handbook or the website for antenna ‘guru’ LB Cebik.?
You should try the EFRW sometime just laying on the ground, or maybe laying across a rock.? I'll say again ... most of the radiating from an AX1 comes from either the counterpoise or the shield of the coax (if not using a common mode choke), and for the majority of uses either of those are lying on or very near the top of the ground.? The surface of most "ground" isn't an RF ground, and if the soil is dry or fairly non-conductive the actual RF ground is probably several feet below the surface.? Not sure what the ground characteristic in the Orkneys is, though.
Dave?? AB7E
On 3/25/2025 12:18 PM, Dan N7CQR via wrote: I forgot to mention that I also carry a EFRW in my little bag,that of course is more efficient than almost short loaded vertical. Mine is Adam’s K6ARK clever design that incorporates a 9:1 balun into the BNC connector. But you have to have either a tree or a pole to toss it into. If you’ve been to the Orkneys you know that there’s not many trees there…?
On Mar 25, 2025, at 11:22, Dan N7CQR via <N7CQR@...> wrote:
It’s a matter of trade offs that each operator is willing to make. No doubt that other larger antennas can be more efficient,but how much are you willing to pack around? Last summer I made a trip to the Orkney Islands,and you are definitely limited in how much baggage you can bring on a very small plane. . Wanting to get some radio time in,it’s an easy decision to bring my small bag and still have room for clothing and other essentials. And I successfully got on the air with the AX1 at 5W. Worked 10 countries in one 45 minute session. For me that’s a good trade off. ?Back home I use the best antenna I can reasonably carry. Lately I’ve been using the Chelegance MC 750 vertical which is a full 1/4 wave on 20-10 Meters with the KH1 and having excellent results. It breaks down into a relatively small package-but still nothing I’d ever fly or take a longer hike with. We have so many great options these days.?
?
--
72 de KB9BVN
|
Re: AX1 - Collapsible Whips
I know when I deploy my AX1/KX2 with an elevated radial or
three...it seems to work a lot better than laying the radials on the
ground.
When I can find something to drape them over.
de KB9BVN
Brian
On 3/26/2025 5:10 PM, Dave AB7E via
groups.io wrote:
toggle quoted message
Show quoted text
The stainless steel used in extendable whip antennas is typically
type 301 or 304, both of which have a relative permeability of
1.05 or less ... which means they are essentially non-magnetic and
don't have much more skin effect than copper or aluminum.? I just
used EZNEC Pro v7 with NEC5 (which does model skin effect) to
model a full size ground plane antenna for 20m using 3/8 inch
diameter tubing (similar to the 17 foot extendable whips) and the
difference in performance between stainless steel and copper
taking into account the difference in both resistivity and
permeability is about 0.16 dB.? Even if the entire 17 foot whip
was only 0.1 inches in diameter the difference is only 0.4 dB.
So no ... it is not a big deal.? The additional loss is
negligible.? The loss in any of these short base loaded
alternatives is FAR greater.
By the way, I also generated a model as close to what I think an
AX1 looks like as I could get.? With a 13 foot counterpoise wire
EZNEC said there is 16 times (!!) more radiated power from the
counterpoise wire than there is from the 4 foot whip.
Dave?? AB7E
On 3/26/2025 6:50 AM, kb1gmx via
groups.io wrote:
?
Generally not a fan of stainless whips, the stainless is
strong but has
high resistance and losses at RF.? Depite that, they are
handy and I
have a few good ones from Buddypole.
?
--
Allison
--------------------------
Please, private email goes to bit bucket
--
72 de KB9BVN
|
Re: matching 6 m 2 element Yagi
Well, I think you understand more than you think, and certainly more
about? antennas than the average ham.
A few years ago I made a 5 element DK7ZB antenna for 6 meters.? The
version I made was one of his models that gives 50 ohms without the
need for the matching system, but it worked great just as I built
it.? I'm a great fan of his work ... he knows what he is doing.? I'm
sure your antenna will work well also, and as I said ... a 1.3 SWR
is not a problem at all.? The loss in gain will not be measurable in
practice and almost any transmitter can handle 1.3 even at power.
Best regards,
Dave?? AB7E
On 3/26/2025 1:49 PM, Martin DK 3 UW
via groups.io wrote:
toggle quoted message
Show quoted text
thanks Dave. In fact I rather don't know, what I am doing. I
just did not want to get an antenna off the shelf and do
something homebrew and the DK7ZB conzept looked easy. But hen on
the first setup something did not match as predicted so I
suspected the? matching stup so I wanted to measure it. Up to
now I only have used the NVNA to trimm antennas to resonance.
?
Martin
DK3UW
|
Re: AX1 - Collapsible Whips
The stainless steel used in extendable whip antennas is typically
type 301 or 304, both of which have a relative permeability of 1.05
or less ... which means they are essentially non-magnetic and don't
have much more skin effect than copper or aluminum.? I just used
EZNEC Pro v7 with NEC5 (which does model skin effect) to model a
full size ground plane antenna for 20m using 3/8 inch diameter
tubing (similar to the 17 foot extendable whips) and the difference
in performance between stainless steel and copper taking into
account the difference in both resistivity and permeability is about
0.16 dB.? Even if the entire 17 foot whip was only 0.1 inches in
diameter the difference is only 0.4 dB.
So no ... it is not a big deal.? The additional loss is negligible.?
The loss in any of these short base loaded alternatives is FAR
greater.
By the way, I also generated a model as close to what I think an AX1
looks like as I could get.? With a 13 foot counterpoise wire EZNEC
said there is 16 times (!!) more radiated power from the
counterpoise wire than there is from the 4 foot whip.
Dave?? AB7E
On 3/26/2025 6:50 AM, kb1gmx via
groups.io wrote:
toggle quoted message
Show quoted text
?
Generally not a fan of stainless whips, the stainless is
strong but has
high resistance and losses at RF.? Depite that, they are
handy and I
have a few good ones from Buddypole.
?
--
Allison
--------------------------
Please, private email goes to bit bucket
_._,_._,_
|
Re: matching 6 m 2 element Yagi
thanks Dave. In fact I rather don't know, what I am doing. I just did not want to get an antenna off the shelf and do something homebrew and the DK7ZB conzept looked easy. But hen on the first setup something did not match as predicted so I suspected the? matching stup so I wanted to measure it. Up to now I only have used the NVNA to trimm antennas to resonance.
?
Martin
DK3UW
|
PALM RADIO paddle & straight key SOLD
Groups,? I've sold my PALM RADIO straight key and paddle. Thanks everyone for your interest and patience
73 Jay W6CJ
|
Re: AX1 - Collapsible Whips
It must be stainless steel because I have left it outside in the rain many times and there is no rust. ? Paul ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Brian KB9BVN via groups.io
Sent: Wednesday, March 26, 2025 3:10 PM
To: [email protected]
Subject: Re: [qrparci] AX1 - Collapsible Whips? Paul is that 25 footer stainless steel?
de KB9BVN
Brian
On 3/26/2025 12:47 PM, Paul Quillen N4LCD via groups.io wrote: Chameleon also has a 25’ extendable whip for $100. Also available at DX Engineering with free shipping due to price. Very well built. ? ? ? The Chameleon whips are built pretty well at the bottom. The early MFJ whips were quite fragile, but the later ones were much better. The Chameleons are still built better than the MFJ items..............
73 de Lee KX4TT On Tuesday, March 25, 2025 at 06:39:40 PM EDT, MIKE N6ZW via groups.io <n6zw@...> wrote: Those are the same that MFJ used to sell before they went closed their doors. I use one for several HB antennas and it works very well alone. You can even base load one easily.? 73,? Mike n6zw On 03/25/2025 3:28 PM PDT Dave AB7E via groups.io <ab7echo@...> wrote:
I forgot to include the link to the SS17 whip:
The pictures in the first review are mine (Alice is my wife's name).
Dave? AB7E
-------- Forwarded Message --------
Except that the AX1 isn't enough of a vertical to actually act like a short vertical.? If you model an AX1 and look at the current distribution you will see that most of it is in the counterpoise wire.? To be honest, the AX1 whip is mostly a convenient lossy tank circuit to act as a counterpoise for the counterpoise wire ... or in some case, the shield of the coax feedline.
I know how to use EZNEC.? I've used it continually since 1993 or so when it was still called ELNEC, and I'm actually a big fan of vertical antennas for portable operation.? My choice, though, is the Chameleon SS17 collapsible whip with elevated radials.? My version weighs about 3.5 pounds ... with steel stakes ... and I can set it up in less than ten minutes.
An an end fed wire doesn't have to be very far off the ground to avoid being a worm warmer.? Why do you think elevated radials work when they are only a foot or two off the ground??? I'm not actually a big fan of end fed wire antennas, but for portable use I don't think they can be beat for performance, size, weight, or cost.? I wish I had an AX1 to compare against various alternatives using WSPR, but I'm not willing to spend the money on one just to prove ... or disprove, if that should be the case ... my point.? Curiously, almost nobody who owns an AX1 has bothered to do a similarly rigorous A-vs-B comparison either.? Presumably, like you, they don't really care as long as "it works".
Dave?? AB7E
On 3/25/2025 2:44 PM, Dan N7CQR via groups.io wrote: I’ve used this strategy on bare summits above 3-4000 feet with some success. Unfortunately at sea level or low elevation you’re just warming the earthworms. Any type of short vertical with an elevated radial will provide a decent takeoff angle. You can model this in EZNEC. A good resource for using short verticals effectively are the writings of Jerry Severns for the ARRL Antenna handbook or the website for antenna ‘guru’ LB Cebik.?
On Mar 25, 2025, at 12:42, Dave AB7E via groups.io <AB7Echo@...> wrote:
You should try the EFRW sometime just laying on the ground, or maybe laying across a rock.? I'll say again ... most of the radiating from an AX1 comes from either the counterpoise or the shield of the coax (if not using a common mode choke), and for the majority of uses either of those are lying on or very near the top of the ground.? The surface of most "ground" isn't an RF ground, and if the soil is dry or fairly non-conductive the actual RF ground is probably several feet below the surface.? Not sure what the ground characteristic in the Orkneys is, though.
Dave?? AB7E
On 3/25/2025 12:18 PM, Dan N7CQR via groups.io wrote: I forgot to mention that I also carry a EFRW in my little bag,that of course is more efficient than almost short loaded vertical. Mine is Adam’s K6ARK clever design that incorporates a 9:1 balun into the BNC connector. But you have to have either a tree or a pole to toss it into. If you’ve been to the Orkneys you know that there’s not many trees there…?
On Mar 25, 2025, at 11:22, Dan N7CQR via groups.io <N7CQR@...> wrote:
It’s a matter of trade offs that each operator is willing to make. No doubt that other larger antennas can be more efficient,but how much are you willing to pack around? Last summer I made a trip to the Orkney Islands,and you are definitely limited in how much baggage you can bring on a very small plane. . Wanting to get some radio time in,it’s an easy decision to bring my small bag and still have room for clothing and other essentials. And I successfully got on the air with the AX1 at 5W. Worked 10 countries in one 45 minute session. For me that’s a good trade off. ?Back home I use the best antenna I can reasonably carry. Lately I’ve been using the Chelegance MC 750 vertical which is a full 1/4 wave on 20-10 Meters with the KH1 and having excellent results. It breaks down into a relatively small package-but still nothing I’d ever fly or take a longer hike with. We have so many great options these days.?
?
--
72 de KB9BVN
|
?? FS: PALM RADIO paddle & straight key
Groups, I'm selling my Palm Radio paddle key and straight key. Both are in good condition.   They were used on a few stealth QRP hotel stays, and then retired. Palm Radio in Germany (Dieter Engels, DJ6TE) closed shop in 2018, so these are rare....I even saw a guy on e-pay trying to sell one for $750!
I'm asking $120 for both, which includes the cost of shipping to a USA address. Terms:? Paypal Family & Friends or personal check.?? Pre-owned, no returns.
Thanks & 73, Jay W6CJ
|
Re: AX1 - Collapsible Whips
Paul is that 25 footer stainless steel?
de KB9BVN
Brian
On 3/26/2025 12:47 PM, Paul Quillen
N4LCD via groups.io wrote:
toggle quoted message
Show quoted text
Chameleon also has a 25’ extendable whip
for $100.
Also available at DX Engineering with free
shipping due to price.
Very well built.
?
?
?
The Chameleon whips are built pretty well
at the bottom. The early MFJ whips were quite fragile, but
the later ones were much better. The Chameleons are still
built better than the MFJ items..............
73 de Lee KX4TT
On
Tuesday, March 25, 2025 at 06:39:40 PM EDT, MIKE N6ZW
via groups.io <n6zw@...>
wrote:
Those
are the same that MFJ used to sell before they
went closed their doors. I use one for several
HB antennas and it works very well alone. You
can even base load one easily.? 73,? Mike n6zw
On
03/25/2025 3:28 PM PDT Dave AB7E via groups.io
<ab7echo@...>
wrote:
I
forgot to include the link to the SS17 whip:
The pictures in the first review are mine
(Alice is my wife's name).
Dave? AB7E
-------- Forwarded Message --------
Except
that the AX1 isn't enough of a vertical to
actually act like a short vertical.? If you
model an AX1 and look at the current
distribution you will see that most of it is
in the counterpoise wire.? To be honest, the
AX1 whip is mostly a convenient lossy tank
circuit to act as a counterpoise for the
counterpoise wire ... or in some case, the
shield of the coax feedline.
I know how to use EZNEC.? I've used it
continually since 1993 or so when it was still
called ELNEC, and I'm actually a big fan of
vertical antennas for portable operation.? My
choice, though, is the Chameleon SS17
collapsible whip with elevated radials.? My
version weighs about 3.5 pounds ... with steel
stakes ... and I can set it up in less than
ten minutes.
An an end fed wire doesn't have to be very far
off the ground to avoid being a worm warmer.?
Why do you think elevated radials work when
they are only a foot or two off the ground???
I'm not actually a big fan of end fed wire
antennas, but for portable use I don't think
they can be beat for performance, size,
weight, or cost.? I wish I had an AX1 to
compare against various alternatives using
WSPR, but I'm not willing to spend the money
on one just to prove ... or disprove, if that
should be the case ... my point.? Curiously,
almost nobody who owns an AX1 has bothered to
do a similarly rigorous A-vs-B comparison
either.? Presumably, like you, they don't
really care as long as "it works".
Dave?? AB7E
On
3/25/2025 2:44 PM, Dan N7CQR via groups.io
wrote:
I’ve
used this strategy on bare summits above
3-4000 feet with some success. Unfortunately
at sea level or low elevation you’re just
warming the earthworms. Any type of short
vertical with an elevated radial will
provide a decent takeoff angle. You can
model this in EZNEC. A good resource for
using short verticals effectively are the
writings of Jerry Severns for the ARRL
Antenna handbook or the website for antenna
‘guru’ LB Cebik.?
On
Mar 25, 2025, at 12:42, Dave AB7E via
groups.io <AB7Echo@...>
wrote:
You
should try the EFRW sometime just laying
on the ground, or maybe laying across a
rock.? I'll say again ... most of the
radiating from an AX1 comes from either
the counterpoise or the shield of the
coax (if not using a common mode choke),
and for the majority of uses either of
those are lying on or very near the top
of the ground.? The surface of most
"ground" isn't an RF ground, and if the
soil is dry or fairly non-conductive the
actual RF ground is probably several
feet below the surface.? Not sure what
the ground characteristic in the Orkneys
is, though.
Dave??
AB7E
On
3/25/2025 12:18 PM, Dan N7CQR via
groups.io wrote:
I
forgot to mention that I also carry a
EFRW in my little bag,that of course
is more efficient than almost short
loaded vertical. Mine is Adam’s K6ARK
clever design that incorporates a 9:1
balun into the BNC connector. But you
have to have either a tree or a pole
to toss it into. If you’ve been to the
Orkneys you know that there’s not many
trees there…?
On
Mar 25, 2025, at 11:22, Dan N7CQR
via groups.io <N7CQR@...>
wrote:
It’s
a matter of trade offs that each
operator is willing to make. No
doubt that other larger antennas
can be more efficient,but how much
are you willing to pack around?
Last summer I made a trip to the
Orkney Islands,and you are
definitely limited in how much
baggage you can bring on a very
small plane. . Wanting to get some
radio time in,it’s an easy
decision to bring my small bag and
still have room for clothing and
other essentials. And I
successfully got on the air with
the AX1 at 5W. Worked 10 countries
in one 45 minute session. For me
that’s a good trade off. ?Back
home I use the best antenna I can
reasonably carry. Lately I’ve been
using the Chelegance MC 750
vertical which is a full 1/4 wave
on 20-10 Meters with the KH1 and
having excellent results. It
breaks down into a relatively
small package-but still nothing
I’d ever fly or take a longer hike
with. We have so many great
options these days.?
--
72 de KB9BVN
|
Re: matching 6 m 2 element Yagi
Personally, I don't think an SWR of 1.4 will give you much problem,
but you might consider using NanoVNASaver (free application) with
your VNA to sweep the frequency from, say, 30 to 60 MHz and save the
result as a Touchstone file (.s1p format).? It is VERY easily done,
and then you can use Zplots by AC6LA (also free) to read that
Touchstone file to plot almost any parameter you want as a function
of frequency ... including resistance and reactance.? It might help
your investigation.
Keep in mind that the reactance of a resistor doesn't change with
frequency, whereas the reactance of the driven element of the
antenna will.? The resistor will only be accurate at (in your case)
37.8 MHz.?
Also, it takes very little difference in the length of a 1/4 wave
stub to make a difference in its transformation.? You obviously know
what you're doing so I'm sure that you are aware that it is a
hyperbolic function in form ... and it will transform BOTH
resistance and reactance.? You could possibly be off just a little
in the physical length or in the estimate of 0.63 for velocity
factor.? I just did a bit of playing around with TLW, the free
transmission line application, and at 50 MHz a difference of only
0.5 inches in length of RG-6 coax changes the reactance of
the input of a quarter wave transmission line terminated in 28 ohms
by 10 ohms.? A difference in velocity factor between 0.63 and 0.64
would also be about 0.5 inches for a quarter wavelength at 50 MHz.
Once you build the antenna, you could probably bring the resonance
almost exactly to the frequency you want by using some sliding
sections of dielectric (like nylon or HDPE).? It has a loading
effect that is variable depending upon where on the driven element
it would be placed ... more effect at the ends where the E-field is
greater and almost no effect at the center.
Just some thoughts ...
Dave?? AB7E
On 3/26/2025 9:35 AM, Martin DK 3 UW
via groups.io wrote:
toggle quoted message
Show quoted text
I am building a 6 m 2 el Yagi dK7ZB design and it is matched
with a transformer made from 75 Ohm coax. 2 stubs of 1/4 Lambda
in parallel. I tohought I could ?put a 28 Ohm resistor replacing
the radiator ?and then have 50 Ohms on the Nano VNA at 50 Mhz
resonnance. ?But that is not, what I see. ?Resonance is 37.8 Mhz
?at 47 Ohms resitance . At 50 Mhz resistance would be 38 Ohms
and SWR 1,4. ?Prior to that I had mesured the coax with a
velocity factor of 1 and could calculate a Velocity factor of
0,63 for the cable which is an unknown TV cable. Then calculated
the lenth with that VF so I thought I should not be too far of.
? Any suggestions ?
?
?
Marin
DK3 UW
|
Re: matching 6 m 2 element Yagi
well I used the VF of 1 to calulate the VF of the Coax . The NVNA showed something like 2,4 m for the real lenth of 1.5m so that calulated a VF of 0.63 for the coax. Then I calculated 75/50,1x0,63 for the coax lenght. One piece with shortened end gives the naround 50 Mhz so that fits. For the Yagi according to DK7ZB it should be 2 coaxes in parallel to tranasform the 28 Ohms to 50 Ohms. Actually I am unable to mesaure that. I would have liked to check that before mounting it to the antenna.
?
?
Martin
DK3UW
|
On Wed, Mar 26, 2025 at 11:25 AM, Michael VE3WMB wrote:
Having 3/8-24 threading at the base means that this antenna can also be extended with Buddipole (or other antenna parts).
Asian and European components frequently have M10 threads, fortunately there are thread adapters available, like this one From Chelegance
The set consists of one male and one female of each thread size so the conversion works either way.? Nicely machined from (presumably) brass, I used mine to adapt a homebrew coil assembly from a European ham to my USA whip, clamp, etc.
73, Don N2vGU
?
|
Re: matching 6 m 2 element Yagi
You need to know what the real VF for the coax used.
That and there is no such thing as a coax with VF=1.
?
Having built that transformer I found with known 1/4 wavelength?
measured using VNA the transformation was very close to the
28 ohms.? However if the VF is incorrect it will be very wrong.
?
For the cable used a cable of VF=1 would be 58 inches(approximate)
but for real 75ohm RG59 VF was .68 was close to 40" and connectors
internal length counted as part of the actual electrical length.
?
Generally TV cable is foamed core with VF closer to .8(not exact
and varies)?and solid insultator cored cables closer to .66 but
until you measure it will be a genralization at best.
?
--
Allison
--------------------------
Please, private email goes to bit bucket
|
Re: matching 6 m 2 element Yagi
Hello Marin,
I assume your goal is to achieve a better match between the antenna and the feed line.
Perhaps you could use a single piece of 75Ω coax, cut to 1/4 Lambda, inserted between the antenna's feed point and your 50Ω feed line.?
If the dipole feed point is close to 72Ω, then this arrangement could be expected to present approximate 60Ω to the 50Ω feed line.?
This should give you a 1.2:1 SWR.??
72 x 50 = 3600, ?? (3600)^0.5 =? 60, ? 60/50 = 1.20 SWR? Not perfect, but close.?
Good luck!? Tom K4AKC
----------------
toggle quoted message
Show quoted text
On 2025-03-26 11:35 am, Martin DK 3 UW via groups.io wrote:
I am building a 6 m 2 el Yagi dK7ZB design and it is matched with a transformer made from 75 Ohm coax. 2 stubs of 1/4 Lambda in parallel. I tohought I could ?put a 28 Ohm resistor replacing the radiator ?and then have 50 Ohms on the Nano VNA at 50 Mhz resonnance. ?But that is not, what I see. ?Resonance is 37.8 Mhz ?at 47 Ohms resitance . At 50 Mhz resistance would be 38 Ohms and SWR 1,4. ?Prior to that I had mesured the coax with a velocity factor of 1 and could calculate a Velocity factor of 0,63 for the cable which is an unknown TV cable. Then calculated the lenth with that VF so I thought I should not be too far of. ? Any suggestions ?
?
?
Marin
DK3 UW
|
Mike.
We are?in violent agreement here. I have the MFJ 1898, essentially the same thing.
I can't understand why so little has been written about?it.? Especially because it usually eliminates the need for a tuner with IC705 and FT817 operations.
At the risk of being thought daft, I also run it on the KX2 handheld with a little bracket.
72 Scott
Doug, I too am enjoying this thread. Do you have a reference for the HB vertical, how it is used/connected, or is it a QRPGuys design? I am always looking for antennas to play with, test and experiment with.?
I am cheap, ie a ham, so bought a used, well priced KX2 that came with an AX1. It has become my favorite POTA activation rig right now, 99% on CW. Set up less than 5 minutes. Most activations when in a bit of a hurry less than 30 minutes. Practical experience indicates that counterpoise placement is important, usually with the radio on the hood of my truck with the counterpoise draped across it. Antenna directly connected to the radio using a printed antenna support.?
When backpacking a lot, I was one of those guys that cut the handle off my toothbrush for efficiency. Weight isn’t as much of an issue today, but bulk is. Doug, I have put together my version of a vertical that will connect directly to the radio. It works, but not much better than the AX1, if at all. Again, almost only CW. Bicycle or walking portable is common.?
72
john, NS6X?
|
Re: AX1 - Collapsible Whips
Chameleon also has a 25’ extendable whip for $100. Also available at DX Engineering with free shipping due to price. Very well built. ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Lee KX4TT via groups.io
Sent: Tuesday, March 25, 2025 11:10 PM
To: [email protected]
Subject: Re: [qrparci] AX1 - Collapsible Whips? The Chameleon whips are built pretty well at the bottom. The early MFJ whips were quite fragile, but the later ones were much better. The Chameleons are still built better than the MFJ items..............
73 de Lee KX4TT On Tuesday, March 25, 2025 at 06:39:40 PM EDT, MIKE N6ZW via groups.io <n6zw@...> wrote: Those are the same that MFJ used to sell before they went closed their doors. I use one for several HB antennas and it works very well alone. You can even base load one easily.? 73,? Mike n6zw On 03/25/2025 3:28 PM PDT Dave AB7E via groups.io <ab7echo@...> wrote:
I forgot to include the link to the SS17 whip:
The pictures in the first review are mine (Alice is my wife's name).
Dave? AB7E
-------- Forwarded Message --------
Except that the AX1 isn't enough of a vertical to actually act like a short vertical.? If you model an AX1 and look at the current distribution you will see that most of it is in the counterpoise wire.? To be honest, the AX1 whip is mostly a convenient lossy tank circuit to act as a counterpoise for the counterpoise wire ... or in some case, the shield of the coax feedline.
I know how to use EZNEC.? I've used it continually since 1993 or so when it was still called ELNEC, and I'm actually a big fan of vertical antennas for portable operation.? My choice, though, is the Chameleon SS17 collapsible whip with elevated radials.? My version weighs about 3.5 pounds ... with steel stakes ... and I can set it up in less than ten minutes.
An an end fed wire doesn't have to be very far off the ground to avoid being a worm warmer.? Why do you think elevated radials work when they are only a foot or two off the ground??? I'm not actually a big fan of end fed wire antennas, but for portable use I don't think they can be beat for performance, size, weight, or cost.? I wish I had an AX1 to compare against various alternatives using WSPR, but I'm not willing to spend the money on one just to prove ... or disprove, if that should be the case ... my point.? Curiously, almost nobody who owns an AX1 has bothered to do a similarly rigorous A-vs-B comparison either.? Presumably, like you, they don't really care as long as "it works".
Dave?? AB7E
On 3/25/2025 2:44 PM, Dan N7CQR via groups.io wrote: I’ve used this strategy on bare summits above 3-4000 feet with some success. Unfortunately at sea level or low elevation you’re just warming the earthworms. Any type of short vertical with an elevated radial will provide a decent takeoff angle. You can model this in EZNEC. A good resource for using short verticals effectively are the writings of Jerry Severns for the ARRL Antenna handbook or the website for antenna ‘guru’ LB Cebik.?
On Mar 25, 2025, at 12:42, Dave AB7E via groups.io <AB7Echo@...> wrote:
You should try the EFRW sometime just laying on the ground, or maybe laying across a rock.? I'll say again ... most of the radiating from an AX1 comes from either the counterpoise or the shield of the coax (if not using a common mode choke), and for the majority of uses either of those are lying on or very near the top of the ground.? The surface of most "ground" isn't an RF ground, and if the soil is dry or fairly non-conductive the actual RF ground is probably several feet below the surface.? Not sure what the ground characteristic in the Orkneys is, though.
Dave?? AB7E
On 3/25/2025 12:18 PM, Dan N7CQR via groups.io wrote: I forgot to mention that I also carry a EFRW in my little bag,that of course is more efficient than almost short loaded vertical. Mine is Adam’s K6ARK clever design that incorporates a 9:1 balun into the BNC connector. But you have to have either a tree or a pole to toss it into. If you’ve been to the Orkneys you know that there’s not many trees there…?
On Mar 25, 2025, at 11:22, Dan N7CQR via groups.io <N7CQR@...> wrote:
It’s a matter of trade offs that each operator is willing to make. No doubt that other larger antennas can be more efficient,but how much are you willing to pack around? Last summer I made a trip to the Orkney Islands,and you are definitely limited in how much baggage you can bring on a very small plane. . Wanting to get some radio time in,it’s an easy decision to bring my small bag and still have room for clothing and other essentials. And I successfully got on the air with the AX1 at 5W. Worked 10 countries in one 45 minute session. For me that’s a good trade off. ?Back home I use the best antenna I can reasonably carry. Lately I’ve been using the Chelegance MC 750 vertical which is a full 1/4 wave on 20-10 Meters with the KH1 and having excellent results. It breaks down into a relatively small package-but still nothing I’d ever fly or take a longer hike with. We have so many great options these days.?
|
matching 6 m 2 element Yagi
I am building a 6 m 2 el Yagi dK7ZB design and it is matched with a transformer made from 75 Ohm coax. 2 stubs of 1/4 Lambda in parallel. I tohought I could ?put a 28 Ohm resistor replacing the radiator ?and then have 50 Ohms on the Nano VNA at 50 Mhz resonnance. ?But that is not, what I see. ?Resonance is 37.8 Mhz ?at 47 Ohms resitance . At 50 Mhz resistance would be 38 Ohms and SWR 1,4. ?Prior to that I had mesured the coax with a velocity factor of 1 and could calculate a Velocity factor of 0,63 for the cable which is an unknown TV cable. Then calculated the lenth with that VF so I thought I should not be too far of. ? Any suggestions ?
?
?
Marin
DK3 UW
|
Doug, I too am enjoying this thread. Do you have a reference for the HB vertical, how it is used/connected, or is it a QRPGuys design? I am always looking for antennas to play with, test and experiment with.?
I am cheap, ie a ham, so bought a used, well priced KX2 that came with an AX1. It has become my favorite POTA activation rig right now, 99% on CW. Set up less than 5 minutes. Most activations when in a bit of a hurry less than 30 minutes. Practical experience indicates that counterpoise placement is important, usually with the radio on the hood of my truck with the counterpoise draped across it. Antenna directly connected to the radio using a printed antenna support.?
When backpacking a lot, I was one of those guys that cut the handle off my toothbrush for efficiency. Weight isn’t as much of an issue today, but bulk is. Doug, I have put together my version of a vertical that will connect directly to the radio. It works, but not much better than the AX1, if at all. Again, almost only CW. Bicycle or walking portable is common.?
72
john, NS6X?
|
John KK4ITX
Brian KB9BVN
Jay W6CJ
Don N2VGU