Date   

Re: February meeting is coming up

Brent Martin
 

I’ll bring a bottle. Brent


On Feb 7, 2019, at 4:36 PM, Brad (the Voice of the Village) Berger <km4ojk@...> wrote:

We need volunteers to sign-up to bring Margaritas for the club to enjoy at Lorenzo's. I brought them last time. Remember the old saying: You can't have too much!

Ole'


Re: February meeting is coming up

Brad (the Voice of the Village) Berger
 

We need volunteers to sign-up to bring Margaritas for the club to enjoy at Lorenzo's. I brought them last time. Remember the old saying: You can't have too much!

Ole'


Re: February meeting is coming up

WK9M
 

Feb 20th looks good for Lorenzo's.

Thanks,
Randy
WK9M

On 2/5/2019 4:19 PM, David Andrews wrote:

The TLARC meeting for February is just around the corner. Mark your calendars for Wednesday evening, February 20th at 7:00 at the Tellico Village Recreation Center. This will be preceded by a dinner at the Lorenzo’s at 5:30. Please email me If you are interested in having dinner, as I’ll need to provide a headcount for dinner.

 

The program for the evening will be a recap of HamCation 2019, which will be held this weekend in Orlando, Florida. Yours truly, N1ESK will be attending for the second year running. Orlando in February – what’s not to love?

 

See you on the 20th,

 

David Andrews, N1ESK, newly drafted TLARC Secretary

 



Re: February meeting is coming up

George Sifnotis
 

David  my wife and I will we coming for dinner. George


On Feb 5, 2019, at 9:11 PM, Brent Martin <brent6851@...> wrote:

David: I’ll be at the dinner. Thanks,Brent 


On Feb 5, 2019, at 4:19 PM, David Andrews <n1esk1@...> wrote:

The TLARC meeting for February is just around the corner. Mark your calendars for Wednesday evening, February 20th at 7:00 at the Tellico Village Recreation Center. This will be preceded by a dinner at the Lorenzo’s at 5:30. Please email me If you are interested in having dinner, as I’ll need to provide a headcount for dinner.

 

The program for the evening will be a recap of HamCation 2019, which will be held this weekend in Orlando, Florida. Yours truly, N1ESK will be attending for the second year running. Orlando in February – what’s not to love?

 

See you on the 20th,

 

David Andrews, N1ESK, newly drafted TLARC Secretary

 


Re: February meeting is coming up

Brent Martin
 

David: I’ll be at the dinner. Thanks,Brent 


On Feb 5, 2019, at 4:19 PM, David Andrews <n1esk1@...> wrote:

The TLARC meeting for February is just around the corner. Mark your calendars for Wednesday evening, February 20th at 7:00 at the Tellico Village Recreation Center. This will be preceded by a dinner at the Lorenzo’s at 5:30. Please email me If you are interested in having dinner, as I’ll need to provide a headcount for dinner.

 

The program for the evening will be a recap of HamCation 2019, which will be held this weekend in Orlando, Florida. Yours truly, N1ESK will be attending for the second year running. Orlando in February – what’s not to love?

 

See you on the 20th,

 

David Andrews, N1ESK, newly drafted TLARC Secretary

 


February meeting is coming up

David Andrews
 

The TLARC meeting for February is just around the corner. Mark your calendars for Wednesday evening, February 20th at 7:00 at the Tellico Village Recreation Center. This will be preceded by a dinner at the Lorenzo’s at 5:30. Please email me If you are interested in having dinner, as I’ll need to provide a headcount for dinner.

 

The program for the evening will be a recap of HamCation 2019, which will be held this weekend in Orlando, Florida. Yours truly, N1ESK will be attending for the second year running. Orlando in February – what’s not to love?

 

See you on the 20th,

 

David Andrews, N1ESK, newly drafted TLARC Secretary

 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Jim Jenkins
 

I’m for the Gap Titan…great performance with a counterpoise and no radials.

JJAA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George Sifnotis via Groups.Io
Sent: Monday, February 4, 2019 1:10 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

I had gotten my decision for a vertical down to 3 

Butternut

Gap titan

And

Cushcraft r8. 

Listening to all here it seems like my first choice of the butternut is the better of the ways

 

What are thoughts 


On Feb 4, 2019, at 12:17 PM, John Haskell via Groups.Io <jasm2213@...> wrote:

Agree with APB, too.

I would not ever recommend a vertical unless the antenna has an extensive set of radials.   Even in the village there is plenty of room in the vast majority of yards for an outside random length OCD.


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

George N2APB
 

Well George, I've had a decade of great service *each* from the Gap Titan and the 5-band Butternut.

My first love was the Gap Titan (with no ground radials) ... I wrote a full perspective on my old club's webpage back in 1999 ... http://www.njqrp.club/data/gap.html

My second love was the Butternut, for the next decade, with about 64 ground radials laid out on the grass and quickly pulled down by nature so I could mow the lawn).  Wonderful bandwidth and I loved the coil at the bottom connecting the antenna to DC ground ... low static and protection for the rig.  I chronicled the installation and successful use of the Butternut on my "Chat With The Designers" webpage at https://www.cwtd.org/Apr17.html.  Check out the podcast of that episode, as we talked about "verticals, Butternut, and stuff" for about 45 minutes.

Can't say anything nice about the Cushcraft R7 (as you now), and I assume they just added another band for the R8 ... so 'nuff said.

So all things considered, I'd first recommend going with the Butternut or Hustler 6BTV (my current antenna here, for low-profile) and put in a *great* ground radial system.  Nothing beats good physics.

But if you want a quicker and simpler antenna installation and can tolerate the 4' on-a-side capacitive skirt, the GAP would do a great job for you.  (You can also put that on a tilt-over base mount to keep it less noticeable, but the need to disconnect/reconnect that cap skirt would be a pain.  Did that for 10 years and eventually just left it up nearly all the time.)

Hope this helps.  And definitely check out the resource links I gave above!

73, George N2APB

PS:  I'll be glad to give a hand when it comes time to install your new antenna system.
PPS: FWIW, I find DX Engineering to be a good source for just about everything I needed in antennas & feedline. 

  
 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

George Sifnotis
 

I had gotten my decision for a vertical down to 3 
Butternut
Gap titan
And
Cushcraft r8. 
Listening to all here it seems like my first choice of the butternut is the better of the ways

What are thoughts 


On Feb 4, 2019, at 12:17 PM, John Haskell via Groups.Io <jasm2213@...> wrote:

Agree with APB, too.

I would not ever recommend a vertical unless the antenna has an extensive set of radials.   Even in the village there is plenty of room in the vast majority of yards for an outside random length OCD.


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

John Haskell <jasm2213@...>
 

Agree with APB, too.

I would not ever recommend a vertical unless the antenna has an extensive set of radials.   Even in the village there is plenty of room in the vast majority of yards for an outside random length OCD.


Stealth Antennas ... for TLARC members

George N2APB
 

Hey all,
With the growing interest we've been seeing in "Stealth Antennas", we've started a new section for our website, exploring and discussing "stealthy ways" for TLARC members to get on the bands in HOA-sensitive communities. 

The most recent addition is the Bird Feeder Vertical, contributed by 
Mike KM4H who recalled the presentation a fellow from the Village did for the ARES group some years back.  Mike says, "The author (Dennis Russell, K9VFU) did a very nice job camouflaging his vertical – you may note that he even glued bird seed to the glass panels to make it look like there was feed inside.  He seemed to do pretty well with it as the logs attached to his program indicate. Maybe this will give some others some useful ideas."  Thanks for the info Mike!


For now just click on the desired antenna type pictured on our TLARC home page to learn more about that one.  Soon, we'll have a dedicated Stealth Antennas page full of additional tried-and-true antennas, references and guidance to enable us all to be on the air from 160m-70cm!

73, George N2APB
TLARC ... http://www.tlarc.org/


PS: Remember the old commercial jingle from back in the 60s? ... "It's Slinky, it's Slinky, the favorite for girls and boys"  This is a hint for the next Stealth Antenna to be explored ;-)

 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Jim Jenkins
 

I’m with George on this one .

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Sunday, February 3, 2019 9:27 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Hi Brad,
Sorry to hear that you got a Cushcraft R7.  It's known as an "air-cooled dummy load" by antenna aficionados because it's a bit shorter than others (maybe 25' or so?)  Unlike most verticals, this one is an end-fed half-wave antenna (EFHWA) that uses a crazy impedance matching network at the hi-z feedpoint to achieve "all band" operation.  Per our discussion, it doesn't require any radials, but it has four 49" rods that decouple the antenna from ground.

The R7 is known for having small bandwidth on 40 and 20, so adjustment to one's favorite place on those bands is important during setup.  Further, it's important to keep your SWR below 3:1 when running higher power (say 300W and up) because the antennas traps (tuned circuits) are susceptible to damage.

Now, as for your question of mounting it horizontally in your attic ... don't.  Half of your radiated power will be going straight up (NVIS on 40 and 80), and the other half will be going down into the house, modulating your electrical wiring, moving your garage door up and down, and likely picking up lots of E-field interference from your power lines in general.  Mounting a "vertical horizontally" (I love the juxtaposition here!) would likely be okay outdoors up in the trees at a good height, like most EFHWAs are.  Plus real EHHWAs would be longer, thus making it more efficient.

I don't mean to be so pessimistic, but just wanted to save you the effort.  Mount it in your backyard on a tilt-over post to make it less obtrusive (and noticeable) when you'e not using it.

73, George N2APB
www.tlarc.org 

 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

George N2APB
 

Hi Brad,
Sorry to hear that you got a Cushcraft R7.  It's known as an "air-cooled dummy load" by antenna aficionados because it's a bit shorter than others (maybe 25' or so?)  Unlike most verticals, this one is an end-fed half-wave antenna (EFHWA) that uses a crazy impedance matching network at the hi-z feedpoint to achieve "all band" operation.  Per our discussion, it doesn't require any radials, but it has four 49" rods that decouple the antenna from ground.

The R7 is known for having small bandwidth on 40 and 20, so adjustment to one's favorite place on those bands is important during setup.  Further, it's important to keep your SWR below 3:1 when running higher power (say 300W and up) because the antennas traps (tuned circuits) are susceptible to damage.

Now, as for your question of mounting it horizontally in your attic ... don't.  Half of your radiated power will be going straight up (NVIS on 40 and 80), and the other half will be going down into the house, modulating your electrical wiring, moving your garage door up and down, and likely picking up lots of E-field interference from your power lines in general.  Mounting a "vertical horizontally" (I love the juxtaposition here!) would likely be okay outdoors up in the trees at a good height, like most EFHWAs are.  Plus real EHHWAs would be longer, thus making it more efficient.

I don't mean to be so pessimistic, but just wanted to save you the effort.  Mount it in your backyard on a tilt-over post to make it less obtrusive (and noticeable) when you'e not using it.

73, George N2APB
www.tlarc.org 

 


Re: KN4DUA activation TODAY for FBYO Winter QRP Contest! (2-Feb)

George N2APB
 

Brief wrap-up ... It was indeed a great afternoon and the bands were alive with the MN State QP, FISTS, FOC, and other activities ... but it was still a struggle working them with only 5 watts.  The Joy of QRP!

That said, I was able to make enough contacts and point to (hopefully) get a certificate for KN4DUA operation in this fun event!  See some pics on the TLARC home page.

73, George N2APB
Home page for TLARC ... http://www.tlarc.org/

 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Brad (the Voice of the Village) Berger
 

Jim and George,

Recently I became the owner of a used Cushcraft R7 antenna. It sounds like it is similar to the 1/2 wave dipoles w/o radials you're discussing. Where does the R7 fit into the food chain of antenna performance? I may be using it with a Yaesu FT-990 I also recently acquired.

The seller said it is the world's greatest antenna and it's what NASA uses to talk to astronauts walking on Mars.

OJK


KN4DUA activation TODAY for FBYO Winter QRP Contest! (2-Feb)

George N2APB
 

Yes, it's rather short notice, but it's SO nice outside that a couple of us decided to activate the TLARC club call for the annual FYBO ("Freeze Your Butt Off") QRP Winter Field Day event! 

We'll be located in plain site up at our favorite spot overlooking the Ft. Loudon Dam, on the "grassy knoll" by the power station.  This event occurs each year on the first Saturday of February, which is usually a cold winter day .. but we got a wonderful gift today with a break from our cold temperatures and we're grabbing our field antennas and headin' for the hills! 

It's a real fun event for CW or phone ... and it's easy:  any, contact counts, even if the other is not FYBO'ing! 

So stop by anytime between 1-3 or so this afternoon to watch, to listen, to make a contact for the club, or to just FYBO in the glorious sunshine today!

72, George N2APB
The home page for TLARC ... http://www.tlarc.org/


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Jim Jenkins
 

I would think about putting the Titan in the attic mounted horizontally. It would take less than 30ft.

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Friday, February 1, 2019 12:51 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Good suggestions Jim.  I’ve used the Gap Titan for years back at the old QTH up north.  Loved its special “loaded half-wave vertical dipole” design, which allows it to operate without ground radials.  (As everyone knows, ground radials are absolutely essential for most other types of verticals.)   Currently here in the new QTH, I have just installed a 6-band, 30-ft Hustler vertical in the backyard, with 32 ground radials out along the grass.  The tilt-over mounting of the antenna allows me to keep it lowered to the ground to avoid neighbor view and concerns.  (I normally operate only when dark, and will soon be painting it brown for when it’s raised during the daytime.)

 

The original purpose of posting this Butterfly Terminated Dipole was to encourage guys here to try an easier and completely stealthy antenna mounting in the attic.  Which is not to say that one couldn’t put an OCF dipole in the attic, even drooping the legs down somewhat at the ends.  And such an OCF in the attic would undoubtedly have better performance than the Terminate Folder Dipole.  But an OCF would likely be unable to reach the lower bands due to the inherently longer length.

 

Hence … antenna experimentation! 

 

George N2APB

 

PS:  We’ll soon talk about just having a “longwire” out the window or to (and into) the trees.  There is some small gauge wire that strong and nearly invisible.  And a simple toroid and capacitor will match it to our transmitters.

 

PPS: Really love your solution for “omni coverage” with the Buckmaster OCF antenna …and envious of the space you obviously have to do that!

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of Jim Jenkins
Sent: Friday, February 1, 2019 7:04 AM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

The 2 antennas I recommend you look at are the 235ft long Buckmaster 8 band which covers 8 hf bands with a 1.5 vswr including 160M or the 135 ft long 7band version which covers all but 160m.  The 3kw versions work better than the 300 watt versions. An antenna that takes less space and works all the hf bands except 160m is the Titan GAP antenna which is a vertical that doesn’t require any radials. The Titan GAP has an omni directional pattern so there are no holes in its coverage. The Buckmaster’s have good coverage for OCF antennas but still have holes off the ends. I’ve put up both an 8band and a 7 band version lined up at 180 degrees crossing near the feed points in the past so the holes of each was filled by the other on all bands except 160m.

Anyway,

Have fun.

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January 31, 2019 10:04 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Hi Jim,

 

That was my first thought too. As they say, even a dummy load will radiate and have flat SWR across such a wide frequency range. 

 

In a more conventional terminated folded dipole, the terminating resistor will lower the overall gain of the antenna at the expense of getting a better SWR across the bands, with much of the power being dissipated as heat in the resistor. As you said, the efficiency stinks but you get broadband coverage. 

 

FYI, there’s a good article on the Terminated Folded Dipole in QST for Sept 2010. 

 

Anyway, Juan suggested it might be worthy of doing some experimentation ... It’s usually fun trying new approaches to antennas, modeling and measuring them, etc.  Learn something every time. 

 

Personally, I’m going the diametrically opposite direction with my experimentation:  I’m constructing a 160m “Small” Transmitting Loop using two turns of 7/8” Heliax with 10’ diameter.  With a vacuum variable capacitor, the loop (inductor) will resonate with SWR of 1.2:1 ... with a 6 KHz bandwidth! 

 

Fun stuff, antenna experimentation!

 

73, George N2APB

 


On Jan 31, 2019, at 8:33 PM, Jim Jenkins <jim@...> wrote:

I would question the efficiency of this antenna as a 16:1 balun wired to a 1200 ohm resister would convert the 1200 ohms to 75 ohms and be low vswr as he measured, but the power would almost all be dissipated in the resister rather radiated. Since the connections are lengths of wire there may be some radiation, but since the currents are very low in the wire due to the 1200 ohm impedance I expect this antenna may measure well, but not work well.

Regards,

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January31, 2019 7:23 PM
To: TLARC@groups.io
Subject: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Build a simple "terminated dipole antenna" for your attic that will operate across the entire HF band ... without an antenna tuner!  

Visit the TLARC home page to learn all about it!

73, George N2APB
www.tlarc.org 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

George N2APB
 

Good suggestions Jim.  I’ve used the Gap Titan for years back at the old QTH up north.  Loved its special “loaded half-wave vertical dipole” design, which allows it to operate without ground radials.  (As everyone knows, ground radials are absolutely essential for most other types of verticals.)   Currently here in the new QTH, I have just installed a 6-band, 30-ft Hustler vertical in the backyard, with 32 ground radials out along the grass.  The tilt-over mounting of the antenna allows me to keep it lowered to the ground to avoid neighbor view and concerns.  (I normally operate only when dark, and will soon be painting it brown for when it’s raised during the daytime.)

 

The original purpose of posting this Butterfly Terminated Dipole was to encourage guys here to try an easier and completely stealthy antenna mounting in the attic.  Which is not to say that one couldn’t put an OCF dipole in the attic, even drooping the legs down somewhat at the ends.  And such an OCF in the attic would undoubtedly have better performance than the Terminate Folder Dipole.  But an OCF would likely be unable to reach the lower bands due to the inherently longer length.

 

Hence … antenna experimentation! 

 

George N2APB

 

PS:  We’ll soon talk about just having a “longwire” out the window or to (and into) the trees.  There is some small gauge wire that strong and nearly invisible.  And a simple toroid and capacitor will match it to our transmitters.

 

PPS: Really love your solution for “omni coverage” with the Buckmaster OCF antenna …and envious of the space you obviously have to do that!

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of Jim Jenkins
Sent: Friday, February 1, 2019 7:04 AM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

The 2 antennas I recommend you look at are the 235ft long Buckmaster 8 band which covers 8 hf bands with a 1.5 vswr including 160M or the 135 ft long 7band version which covers all but 160m.  The 3kw versions work better than the 300 watt versions. An antenna that takes less space and works all the hf bands except 160m is the Titan GAP antenna which is a vertical that doesn’t require any radials. The Titan GAP has an omni directional pattern so there are no holes in its coverage. The Buckmaster’s have good coverage for OCF antennas but still have holes off the ends. I’ve put up both an 8band and a 7 band version lined up at 180 degrees crossing near the feed points in the past so the holes of each was filled by the other on all bands except 160m.

Anyway,

Have fun.

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January 31, 2019 10:04 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Hi Jim,

 

That was my first thought too. As they say, even a dummy load will radiate and have flat SWR across such a wide frequency range. 

 

In a more conventional terminated folded dipole, the terminating resistor will lower the overall gain of the antenna at the expense of getting a better SWR across the bands, with much of the power being dissipated as heat in the resistor. As you said, the efficiency stinks but you get broadband coverage. 

 

FYI, there’s a good article on the Terminated Folded Dipole in QST for Sept 2010. 

 

Anyway, Juan suggested it might be worthy of doing some experimentation ... It’s usually fun trying new approaches to antennas, modeling and measuring them, etc.  Learn something every time. 

 

Personally, I’m going the diametrically opposite direction with my experimentation:  I’m constructing a 160m “Small” Transmitting Loop using two turns of 7/8” Heliax with 10’ diameter.  With a vacuum variable capacitor, the loop (inductor) will resonate with SWR of 1.2:1 ... with a 6 KHz bandwidth! 

 

Fun stuff, antenna experimentation!

 

73, George N2APB

 


On Jan 31, 2019, at 8:33 PM, Jim Jenkins <jim@...> wrote:

I would question the efficiency of this antenna as a 16:1 balun wired to a 1200 ohm resister would convert the 1200 ohms to 75 ohms and be low vswr as he measured, but the power would almost all be dissipated in the resister rather radiated. Since the connections are lengths of wire there may be some radiation, but since the currents are very low in the wire due to the 1200 ohm impedance I expect this antenna may measure well, but not work well.

Regards,

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January31, 2019 7:23 PM
To: TLARC@groups.io
Subject: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Build a simple "terminated dipole antenna" for your attic that will operate across the entire HF band ... without an antenna tuner!  

Visit the TLARC home page to learn all about it!

73, George N2APB
www.tlarc.org 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Jim Jenkins
 

By the way, If you don’t quite have the 235 ft, you can let each end hang vertically for 10 to 20 feet and have almost no affect on performance.

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January 31, 2019 10:04 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Hi Jim,

 

That was my first thought too. As they say, even a dummy load will radiate and have flat SWR across such a wide frequency range. 

 

In a more conventional terminated folded dipole, the terminating resistor will lower the overall gain of the antenna at the expense of getting a better SWR across the bands, with much of the power being dissipated as heat in the resistor. As you said, the efficiency stinks but you get broadband coverage. 

 

FYI, there’s a good article on the Terminated Folded Dipole in QST for Sept 2010. 

 

Anyway, Juan suggested it might be worthy of doing some experimentation ... It’s usually fun trying new approaches to antennas, modeling and measuring them, etc.  Learn something every time. 

 

Personally, I’m going the diametrically opposite direction with my experimentation:  I’m constructing a 160m “Small” Transmitting Loop using two turns of 7/8” Heliax with 10’ diameter.  With a vacuum variable capacitor, the loop (inductor) will resonate with SWR of 1.2:1 ... with a 6 KHz bandwidth! 

 

Fun stuff, antenna experimentation!

 

73, George N2APB

 


On Jan 31, 2019, at 8:33 PM, Jim Jenkins <jim@...> wrote:

I would question the efficiency of this antenna as a 16:1 balun wired to a 1200 ohm resister would convert the 1200 ohms to 75 ohms and be low vswr as he measured, but the power would almost all be dissipated in the resister rather radiated. Since the connections are lengths of wire there may be some radiation, but since the currents are very low in the wire due to the 1200 ohm impedance I expect this antenna may measure well, but not work well.

Regards,

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January 31, 2019 7:23 PM
To: TLARC@groups.io
Subject: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Build a simple "terminated dipole antenna" for your attic that will operate across the entire HF band ... without an antenna tuner!  

Visit the TLARC home page to learn all about it!

73, George N2APB
www.tlarc.org 


Re: The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

Jim Jenkins
 

The 2 antennas I recommend you look at are the 235ft long Buckmaster 8 band which covers 8 hf bands with a 1.5 vswr including 160M or the 135 ft long 7band version which covers all but 160m.  The 3kw versions work better than the 300 watt versions. An antenna that takes less space and works all the hf bands except 160m is the Titan GAP antenna which is a vertical that doesn’t require any radials. The Titan GAP has an omni directional pattern so there are no holes in its coverage. The Buckmaster’s have good coverage for OCF antennas but still have holes off the ends. I’ve put up both an 8band and a 7 band version lined up at 180 degrees crossing near the feed points in the past so the holes of each was filled by the other on all bands except 160m.

Anyway,

Have fun.

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January 31, 2019 10:04 PM
To: TLARC@groups.io
Subject: Re: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Hi Jim,

 

That was my first thought too. As they say, even a dummy load will radiate and have flat SWR across such a wide frequency range. 

 

In a more conventional terminated folded dipole, the terminating resistor will lower the overall gain of the antenna at the expense of getting a better SWR across the bands, with much of the power being dissipated as heat in the resistor. As you said, the efficiency stinks but you get broadband coverage. 

 

FYI, there’s a good article on the Terminated Folded Dipole in QST for Sept 2010. 

 

Anyway, Juan suggested it might be worthy of doing some experimentation ... It’s usually fun trying new approaches to antennas, modeling and measuring them, etc.  Learn something every time. 

 

Personally, I’m going the diametrically opposite direction with my experimentation:  I’m constructing a 160m “Small” Transmitting Loop using two turns of 7/8” Heliax with 10’ diameter.  With a vacuum variable capacitor, the loop (inductor) will resonate with SWR of 1.2:1 ... with a 6 KHz bandwidth! 

 

Fun stuff, antenna experimentation!

 

73, George N2APB

 


On Jan 31, 2019, at 8:33 PM, Jim Jenkins <jim@...> wrote:

I would question the efficiency of this antenna as a 16:1 balun wired to a 1200 ohm resister would convert the 1200 ohms to 75 ohms and be low vswr as he measured, but the power would almost all be dissipated in the resister rather radiated. Since the connections are lengths of wire there may be some radiation, but since the currents are very low in the wire due to the 1200 ohm impedance I expect this antenna may measure well, but not work well.

Regards,

Jim

AA1J

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of George N2APB
Sent: Thursday, January31, 2019 7:23 PM
To: TLARC@groups.io
Subject: [TLARC] The Broadband Butterfly ... an HOA-friendly all-HF antenna for your attic

 

Build a simple "terminated dipole antenna" for your attic that will operate across the entire HF band ... without an antenna tuner!  

Visit the TLARC home page to learn all about it!

73, George N2APB
www.tlarc.org 

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