Topics

How do I best operate a 4S-Tuner with a Doublet antenna ?


Bob KM6BMX
 

Hello, 

  I plan to operate my 4S-Tuner with a 40m "Doublet" antenna.  The doublet has two 1-wire legs, 22 feet each, with a 28 foot 2-wire feedline, which I assume is "balanced". (See URLs below for details). 
 
  I have 2 questions. 
 
    I recently re-read the manual, which states the following:  "With an external balun it will also match antennas with balanced feedlines."  However, there are 2 binding posts that share the same internal circuit connection as the output BNC connector ("ANT"). 
  
  Q1:  Can I just connect the "balanced" 2-wire feedline directly to the posts, picking one as the "antenna" and the other as "ground"? 
  
  On a related note, it seems that the 4S-Tuner is geared primarily towards high-impedance antennas, such as EFHW. 
 
  Q2:  How does it perform with an antenna with an impedance close to the nominal 50 ohms? 
  
  Thanks much for your insights!
 
Cheers & 73,
Bob KM6BMX  
--  central AZ
  
========================================
 
    NorCal "Crappie" antenna 
  http://www.norcalqrp.org/crappieantenna.htm
  
NorCal "Doublet" antenna
  http://www.norcalqrp.org/norcaldoublet.htm
 
========================================
 


Frank Perkins
 

Hi,
At only 22ft per leg, sounds like you might have a 30 meter dipole, resonant around 10 mHz.
Adding a 4 to 1 BALUN will take the balanced feedline to balanced 50 ohms to enter your tuner.
Frank N6CES

On Sat, Apr 13, 2019, 7:23 PM Bob KM6BMX <km6bmx@...> wrote:
Hello, 

  I plan to operate my 4S-Tuner with a 40m "Doublet" antenna.  The doublet has two 1-wire legs, 22 feet each, with a 28 foot 2-wire feedline, which I assume is "balanced". (See URLs below for details). 
 
  I have 2 questions. 
 
    I recently re-read the manual, which states the following:  "With an external balun it will also match antennas with balanced feedlines."  However, there are 2 binding posts that share the same internal circuit connection as the output BNC connector ("ANT"). 
  
  Q1:  Can I just connect the "balanced" 2-wire feedline directly to the posts, picking one as the "antenna" and the other as "ground"? 
  
  On a related note, it seems that the 4S-Tuner is geared primarily towards high-impedance antennas, such as EFHW. 
 
  Q2:  How does it perform with an antenna with an impedance close to the nominal 50 ohms? 
  
  Thanks much for your insights!
 
Cheers & 73,
Bob KM6BMX  
--  central AZ
  
========================================
 
    NorCal "Crappie" antenna 
  
NorCal "Doublet" antenna
 
========================================
 


Frank Perkins
 

Hi Bob,
What you have should work fine.
After I read your attached article, I discovered it's not a standard 40 meter  dipole.
Your feedline type alters the dipole design to allow a shorter leg length, and allow multiband performance.
You should get results attaching the feedline do the tuner, and probably some improvement with the 4 to 1 BALUN.
Cheers,
Frank N6CES



On Sat, Apr 13, 2019, 10:03 PM Frank Perkins via Groups.Io <N6CES.r=gmail.com@groups.io> wrote:
Hi,
At only 22ft per leg, sounds like you might have a 30 meter dipole, resonant around 10 mHz.
Adding a 4 to 1 BALUN will take the balanced feedline to balanced 50 ohms to enter your tuner.
Frank N6CES

On Sat, Apr 13, 2019, 7:23 PM Bob KM6BMX <km6bmx@...> wrote:
Hello, 

  I plan to operate my 4S-Tuner with a 40m "Doublet" antenna.  The doublet has two 1-wire legs, 22 feet each, with a 28 foot 2-wire feedline, which I assume is "balanced". (See URLs below for details). 
 
  I have 2 questions. 
 
    I recently re-read the manual, which states the following:  "With an external balun it will also match antennas with balanced feedlines."  However, there are 2 binding posts that share the same internal circuit connection as the output BNC connector ("ANT"). 
  
  Q1:  Can I just connect the "balanced" 2-wire feedline directly to the posts, picking one as the "antenna" and the other as "ground"? 
  
  On a related note, it seems that the 4S-Tuner is geared primarily towards high-impedance antennas, such as EFHW. 
 
  Q2:  How does it perform with an antenna with an impedance close to the nominal 50 ohms? 
  
  Thanks much for your insights!
 
Cheers & 73,
Bob KM6BMX  
--  central AZ
  
========================================
 
    NorCal "Crappie" antenna 
  
NorCal "Doublet" antenna
 
========================================
 


KB9BVN - <kb9bvn@...>
 

Sounds like a Norcal Doublet....


4S tuner is designed to work best with random wire antennas. 

But I'd try it anyway. 



On Sat, Apr 13, 2019 at 10:23 PM Bob KM6BMX <km6bmx@...> wrote:
Hello, 

  I plan to operate my 4S-Tuner with a 40m "Doublet" antenna.  The doublet has two 1-wire legs, 22 feet each, with a 28 foot 2-wire feedline, which I assume is "balanced". (See URLs below for details). 
 
  I have 2 questions. 
 
    I recently re-read the manual, which states the following:  "With an external balun it will also match antennas with balanced feedlines."  However, there are 2 binding posts that share the same internal circuit connection as the output BNC connector ("ANT"). 
  
  Q1:  Can I just connect the "balanced" 2-wire feedline directly to the posts, picking one as the "antenna" and the other as "ground"? 
  
  On a related note, it seems that the 4S-Tuner is geared primarily towards high-impedance antennas, such as EFHW. 
 
  Q2:  How does it perform with an antenna with an impedance close to the nominal 50 ohms? 
  
  Thanks much for your insights!
 
Cheers & 73,
Bob KM6BMX  
--  central AZ
  
========================================
 
    NorCal "Crappie" antenna 
  
NorCal "Doublet" antenna
 
========================================
 



--
73 de KB9BVN
Brian Murrey


Bob KM6BMX
 

Hi all,

  Thanks for the replies.

  Frank, you mentioned a 4:1 balun. If I am connecting the 2-wire feedline directly to the tuner binding posts, how do I make / find a "bal-bal"? Or, are you suggesting that I use an actual 4:1 balun (2-wire feedline on one side, coax connector on the other side, and multiple turns of coax in between) and hook that to the coax antenna connector on the tuner?

  If I understand correctly, at 40m the Doublet will present roughly 50 ohms to the tuner. Since I can dial out most of the inductance and capacitance with the 3 knobs, I should be able to match with low SWR fairly quickly. 

  At harmonic shorter bands (20m, 15m, 10m), the Doublet will likely present with a higher impedance. Then, I can dial in increasing amounts of inductance and capacitance to match the antenna to the transceiver operating at the higher frequencies.

  I think that the tuner will really shine with some of other HF bands (30m, 17m, 12m). At those frequencies,  the Doublet will truly present as a "random wire".

  As you all say, I will know when I try it. Now that I have a feasible and highly portable antenna and tuner, I need to find a small HF transceiver to actually operate. Perhaps I can bring it to a Field Day or other operating event somewhere in central AZ and ask if I can try it with one of their rigs. 

  For my own rig, I am waiting until Hans Summer releases his QSX multi-mode all-HF band QRP transceiver. I Hopefully, his QRP Labs ( http://www.qrp-labs.com ) will make those available sometime this summer of 2019. 

  I am not yet CW capable and won't have time to learn Morse code anytime soon. Thus, I need a rig that supports SSB and maybe even some of the digital modes ( RTTY, PSK31, Olivia, FT-x, etc.)

Cheers & 73,
Bob KM6BMX
--  central AZ


Frank Perkins
 

Hi Bob,
Antennas are the magic part of ham radio.
Your 4sqrp tuner is a great one, basically designed for use with a "random length wire" antenna and a counterpoise wire.
For portable use, the antenna could be anywhere from 20 to 80 feet, and the counterpoise from 4 to 15 feet.
The antenna wire on the red binding post and counterpoise on the black post.
However, you are using a dipole antenna with a balanced feedline.
I would first try it connected to the red & black binding posts, and see what results you get (signal strength and direction determined by call zones received). Then switch the feedline wires and test again. Then twist both feedline wires together onto the red post and a 10 ft counterpoise wire on the black post.
Compare data. Which gave best results?
A typical dipole at about 40 ft off the ground running North and South will have the best coverage to the East and West. If only 10 to 12 feet high, it will be NVIS and work best on 40, 80, & 160, and give omnidirectional 300-500 mile range.
Later, you can build a little 1:1 and 4:1 BALUN to try between the feedline pair and the posts.
That's the fun of antennas.
I don't think you mentioned what type of rig you have, but if it's portable, take it to a park with a spool of lightweight wire.
Take a fishing pole with a 1-1/2oz sinker, sling it into a tree, pull the end of the antenna wire into the tree and have a blast!
Cheers,
Frank N6CES

On Tue, Apr 16, 2019, 6:58 AM Bob KM6BMX <km6bmx@...> wrote:
Hi all,

  Thanks for the replies.

  Frank, you mentioned a 4:1 balun. If I am connecting the 2-wire feedline directly to the tuner binding posts, how do I make / find a "bal-bal"? Or, are you suggesting that I use an actual 4:1 balun (2-wire feedline on one side, coax connector on the other side, and multiple turns of coax in between) and hook that to the coax antenna connector on the tuner?

  If I understand correctly, at 40m the Doublet will present roughly 50 ohms to the tuner. Since I can dial out most of the inductance and capacitance with the 3 knobs, I should be able to match with low SWR fairly quickly. 

  At harmonic shorter bands (20m, 15m, 10m), the Doublet will likely present with a higher impedance. Then, I can dial in increasing amounts of inductance and capacitance to match the antenna to the transceiver operating at the higher frequencies.

  I think that the tuner will really shine with some of other HF bands (30m, 17m, 12m). At those frequencies,  the Doublet will truly present as a "random wire".

  As you all say, I will know when I try it. Now that I have a feasible and highly portable antenna and tuner, I need to find a small HF transceiver to actually operate. Perhaps I can bring it to a Field Day or other operating event somewhere in central AZ and ask if I can try it with one of their rigs. 

  For my own rig, I am waiting until Hans Summer releases his QSX multi-mode all-HF band QRP transceiver. I Hopefully, his QRP Labs ( http://www.qrp-labs.com ) will make those available sometime this summer of 2019. 

  I am not yet CW capable and won't have time to learn Morse code anytime soon. Thus, I need a rig that supports SSB and maybe even some of the digital modes ( RTTY, PSK31, Olivia, FT-x, etc.)

Cheers & 73,
Bob KM6BMX
--  central AZ


John - KK4ITX
 

Bob,

I have been using WSPR for a couple of years now to check the effectiveness of my antennas for TX & RX.  In just a few minutes you can see just how your system is working, make some changes and re-test.  

I also check WSPR almost daily for real propagation in real time....... not a prediction but current condx and a map showing actual current results for any band.

WSPR (IPad/IPhone) APP or WSPRnet (computer software) are free offerings.  I am currently working on a presentation on this subject for a local club, if it all comes together I’ll share it with the group. (Use Google to find them).

As many, many have said before us, the antenna (including the feed line) is the most important part of your system....... almost 1400 miles between us, I was at 5w on an Inverted V and SHE was running 2w into a 3 element beam during not so great band condx.

Love to play with wire !

John
KK4ITX 

If you need a parachute and don't have one you probably won't need one again.

On Apr 16, 2019, at 16:37, Frank Perkins <N6CES.r@...> wrote:

Hi Bob,
Antennas are the magic part of ham radio.
Your 4sqrp tuner is a great one, basically designed for use with a "random length wire" antenna and a counterpoise wire.
For portable use, the antenna could be anywhere from 20 to 80 feet, and the counterpoise from 4 to 15 feet.
The antenna wire on the red binding post and counterpoise on the black post.
However, you are using a dipole antenna with a balanced feedline.
I would first try it connected to the red & black binding posts, and see what results you get (signal strength and direction determined by call zones received). Then switch the feedline wires and test again. Then twist both feedline wires together onto the red post and a 10 ft counterpoise wire on the black post.
Compare data. Which gave best results?
A typical dipole at about 40 ft off the ground running North and South will have the best coverage to the East and West. If only 10 to 12 feet high, it will be NVIS and work best on 40, 80, & 160, and give omnidirectional 300-500 mile range.
Later, you can build a little 1:1 and 4:1 BALUN to try between the feedline pair and the posts.
That's the fun of antennas.
I don't think you mentioned what type of rig you have, but if it's portable, take it to a park with a spool of lightweight wire.
Take a fishing pole with a 1-1/2oz sinker, sling it into a tree, pull the end of the antenna wire into the tree and have a blast!
Cheers,
Frank N6CES

On Tue, Apr 16, 2019, 6:58 AM Bob KM6BMX <km6bmx@...> wrote:
Hi all,

  Thanks for the replies.

  Frank, you mentioned a 4:1 balun. If I am connecting the 2-wire feedline directly to the tuner binding posts, how do I make / find a "bal-bal"? Or, are you suggesting that I use an actual 4:1 balun (2-wire feedline on one side, coax connector on the other side, and multiple turns of coax in between) and hook that to the coax antenna connector on the tuner?

  If I understand correctly, at 40m the Doublet will present roughly 50 ohms to the tuner. Since I can dial out most of the inductance and capacitance with the 3 knobs, I should be able to match with low SWR fairly quickly. 

  At harmonic shorter bands (20m, 15m, 10m), the Doublet will likely present with a higher impedance. Then, I can dial in increasing amounts of inductance and capacitance to match the antenna to the transceiver operating at the higher frequencies.

  I think that the tuner will really shine with some of other HF bands (30m, 17m, 12m). At those frequencies,  the Doublet will truly present as a "random wire".

  As you all say, I will know when I try it. Now that I have a feasible and highly portable antenna and tuner, I need to find a small HF transceiver to actually operate. Perhaps I can bring it to a Field Day or other operating event somewhere in central AZ and ask if I can try it with one of their rigs. 

  For my own rig, I am waiting until Hans Summer releases his QSX multi-mode all-HF band QRP transceiver. I Hopefully, his QRP Labs ( http://www.qrp-labs.com ) will make those available sometime this summer of 2019. 

  I am not yet CW capable and won't have time to learn Morse code anytime soon. Thus, I need a rig that supports SSB and maybe even some of the digital modes ( RTTY, PSK31, Olivia, FT-x, etc.)

Cheers & 73,
Bob KM6BMX
--  central AZ


Jeff Logullo N0̸MII
 

Speaking of magic/fun, and antenna experimentation, and balanced wire feedline... you might consider adding a z-match tuner to your arsenal of ham goodies. Something like:


Both tuners are great designs, but are targeted at different types of antennas. A tuner like this one may be a better choice for your balanced feedline.

Try both -- experiment! WSPR and/or the RBN can help you evaluate how things are working. Have fun!

Jeff N0̸MII 


On Apr 16, 2019, at 9:34 PM, jleahy00 via Groups.Io <jleahy00@...> wrote:

I have been using WSPR for a couple of years now to check the effectiveness of my antennas for TX & RX.  In just a few minutes you can see just how your system is working, make some changes and re-test.  

On Apr 16, 2019, at 16:37, Frank Perkins <N6CES.r@...> wrote:

Hi Bob,
Antennas are the magic part of ham radio.
Your 4sqrp tuner is a great one, basically designed for use with a "random length wire" antenna and a counterpoise wire.



--
Jeff N0̷MII


Gwen Patton
 

I've got an Emtech ZM-2 I built about a decade ago. Still works like a champ. It'll frequently tune what my Elecraft T1 won't. I needed to use it for my Cricket 30 because the antenna was really lousy, and the Cricket wasn't putting out enough power for the T1. I might get one of those QRPGuys multi-tuners, though, that looks sharp. I've got a lot of their other gear.

On Tue, Apr 16, 2019 at 11:00 PM Jeff Logullo N0̸MII <jeff@...> wrote:
Speaking of magic/fun, and antenna experimentation, and balanced wire feedline... you might consider adding a z-match tuner to your arsenal of ham goodies. Something like:


Both tuners are great designs, but are targeted at different types of antennas. A tuner like this one may be a better choice for your balanced feedline.

Try both -- experiment! WSPR and/or the RBN can help you evaluate how things are working. Have fun!

Jeff N0̸MII 


On Apr 16, 2019, at 9:34 PM, jleahy00 via Groups.Io <jleahy00@...> wrote:

I have been using WSPR for a couple of years now to check the effectiveness of my antennas for TX & RX.  In just a few minutes you can see just how your system is working, make some changes and re-test.  

On Apr 16, 2019, at 16:37, Frank Perkins <N6CES.r@...> wrote:

Hi Bob,
Antennas are the magic part of ham radio.
Your 4sqrp tuner is a great one, basically designed for use with a "random length wire" antenna and a counterpoise wire.



--
Jeff N0̷MII



--

-+-+-+-+-
Jenny Everywhere's Infinite: Quark Time
http://quarktime.net