Date   
Re: Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

John Faivre
 

Yes. I have been using it for 4 months. WAS in 3 months FT8. This is a new problem.
--
John Faivre WA9SGD

Re: Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

John Faivre
 

I suspected a sticky relay. I’ll try replacing it. 
--
John Faivre WA9SGD

Re: Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

Jens Kaemmerer
 

I had the same problem and narrowed this problem down the K1 relay by measuring
the relay outputs for K1 and K3.

I decided to replace the K1 relay and have had no issues ever since.

Replacing a relay was quite an undertaking because I had to somehow
desolder 8 pins simultaneously. After trying out various methods without
success (removing solder with desolder braid, etc.) I created a U shaped
'heat transfer' device out of 1 mm copper wire and re-added solder
to connect the 8 pins with the 'heat transfer' device. Holding the
soldering iron to the 'heat transfer' device then allowed me to slowly
remove the old relay. Then I cleaned up the through holes with desolder
braid and installed the new relay.

-jens (KM6ZJV)

Re: Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

David Nelson
 

I looked online and bought an iron with built in solder sucker. Used it to
replace all the relays on my board and it worked perfectly.. the relays popped
right out and the holes were left clean. New relays popped right in. no problems
at all.     Dave    kc2ipx

Re: Mag Loop for HOA's??

Jack, W8TEE
 

I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

MadRadioModder
 

I’ve got one (MFJ loop that someone gave me) too and have thought about automating the tuning of the loop.  Once the schematic is available for Jack & Al’s controller I can tell you if, with slight mods, it will work for the MFJ…

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jack Purdum via Groups.Io
Sent: Tuesday, June 25, 2019 10:21 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Mag Loop for HOA's??

 

I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

 

Jack, W8TEE

 

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:

 

 

Jack,


Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN


Virus-free. www.avg.com

--

…_. _._

Re: Mag Loop for HOA's??

Robert D. Bowers
 

Unless they changed the design, I've got the parts of their loop (belongs to a friend that I haven't seen or heard from in years) back in storage.  It could be done, although you'd have to come up with changes to the mechanism between the motor and cap.  The motor on his was way too fast for his liking, and we'd talked about building an automated system, using steppers or a motor with a really big gear reduction.

I've got some old (semi) hard line that I've been thinking about making into a loop antenna.  The conductors (including external shielding) are solid copper, and we'd come up with an alternative form of tuning capacitor which should work well.  Problem is, I have too many things to deal with as it is and no income, so everything must be scrounged (and that usually takes a lot of time) - so it's on the back burner for the future.


On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

Robert D. Bowers
 

(Laugh) I got ahead of myself.

The Antenna belonging to my friend was easily taken apart, btw.

On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

jsternmd
 

Are the Axicom relays still preferred over the ones provided in Ubitx v5?

 

Jerry

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of David Nelson
Sent: Tuesday, June 25, 2019 11:15 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Ubitx occasionally hanging in transmit while receive led is on. Have to hit cw key a few times to get it unstuck. Ideas? #ubitx

 

I looked online and bought an iron with built in solder sucker. Used it to

replace all the relays on my board and it worked perfectly.. the relays popped

right out and the holes were left clean. New relays popped right in. no problems

at all.     Dave    kc2ipx

Re: Mag Loop for HOA's??

Jack, W8TEE
 

Does that void their warrantee?

Jack, W8TEE

On Tuesday, June 25, 2019, 12:38:53 PM EDT, Robert D. Bowers <n4fbz@...> wrote:


(Laugh) I got ahead of myself.

The Antenna belonging to my friend was easily taken apart, btw.

On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

Jack, W8TEE
 

We are using this stepper controller:

which can be purchased online for under $10. Our NEMA 17 stepper motor has 200 steps/revolution, or 1.8º. The table you see printed on the controller refers to switch settings that you can use to control the stepper. It allows you to "subdivide" that 1.8º by 32, which gives a really small nudge in the stepper. It works well.

Jack, W8TEE



On Tuesday, June 25, 2019, 12:38:00 PM EDT, Robert D. Bowers <n4fbz@...> wrote:


Unless they changed the design, I've got the parts of their loop (belongs to a friend that I haven't seen or heard from in years) back in storage.  It could be done, although you'd have to come up with changes to the mechanism between the motor and cap.  The motor on his was way too fast for his liking, and we'd talked about building an automated system, using steppers or a motor with a really big gear reduction.

I've got some old (semi) hard line that I've been thinking about making into a loop antenna.  The conductors (including external shielding) are solid copper, and we'd come up with an alternative form of tuning capacitor which should work well.  Problem is, I have too many things to deal with as it is and no income, so everything must be scrounged (and that usually takes a lot of time) - so it's on the back burner for the future.


On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

Art N4EZZ
 

Jack,

When might we get some more details, dimensions, schematics, BOM, code?
If there is more information available I must have missed it. I would
like to start stocking up on parts.

In reference to Field Day you mentioned 40 and 20 meters, will this
design extend to 80?

Thanks, I do appreciate all that you and Al are doing to encourage
interest in building things for Ham radio.

If Al doesn't like the "luggable double double" why don't you call it
the "JackAl Mag Double" or even shorter "AJ Mag Double".

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
In any given circuit, the most expensive part will always sacrifice
itself to protect the fuse.

On 6/25/19 9:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.
Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:

Jack,
Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.

Re: uBitx not receiving well on CWU or CWL

Sam Tedesco
 

Re: Mag Loop for HOA's??

Robert D. Bowers
 

It depends on how long the warranty lasts.  He'd had his over a year (maybe a couple of years - or more), and I doubt that the warranty would be longer than that.

They may have changed the design since he got his loop, but I think it's more likely that they didn't.


On 6/25/19 1:02 PM, Jack Purdum via Groups.Io wrote:
Does that void their warrantee?

Jack, W8TEE

On Tuesday, June 25, 2019, 12:38:53 PM EDT, Robert D. Bowers <n4fbz@...> wrote:


(Laugh) I got ahead of myself.

The Antenna belonging to my friend was easily taken apart, btw.

On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

SAM R BURNES
 

Found this one on Amazon, is it the same model?

TB6600 4A 9-42V Stepper Motor Driver CNC Controller, Stepper Motor Driver Nema tb6600 Single Axes Two Phase Hybrid Stepper Motor for CNC





Sorry about the size, using a Mac and have no idea how to size it. 

Priced at about $13.00.

Sam
WY8V

On Jun 25, 2019, at 12:08 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:

We are using this stepper controller:

<dummyfile.0.part>
which can be purchased online for under $10. Our NEMA 17 stepper motor has 200 steps/revolution, or 1.8º. The table you see printed on the controller refers to switch settings that you can use to control the stepper. It allows you to "subdivide" that 1.8º by 32, which gives a really small nudge in the stepper. It works well.

Jack, W8TEE



On Tuesday, June 25, 2019, 12:38:00 PM EDT, Robert D. Bowers <n4fbz@...> wrote:


Unless they changed the design, I've got the parts of their loop (belongs to a friend that I haven't seen or heard from in years) back in storage.  It could be done, although you'd have to come up with changes to the mechanism between the motor and cap.  The motor on his was way too fast for his liking, and we'd talked about building an automated system, using steppers or a motor with a really big gear reduction.

I've got some old (semi) hard line that I've been thinking about making into a loop antenna.  The conductors (including external shielding) are solid copper, and we'd come up with an alternative form of tuning capacitor which should work well.  Problem is, I have too many things to deal with as it is and no income, so everything must be scrounged (and that usually takes a lot of time) - so it's on the back burner for the future.


On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

Jack, W8TEE
 

 Art:

Al had a vacuum variable cap (VVC) with a different range and he was able to get it to work on 80M-20M, but the problem is setting the limit switches for a VVC. The pillow blocks and threads cost about $30 then add in the micro switches and the VVC. Al had an air cap that would work for 40-30-20M, so that's what we tried as it was less expensive. Also, the likelihood of someone having a usable air VC lying around unemployed is more likely that a VVC. I will be using a VVC on mine since I have a very small VVC I just picked up in Dayton that will be easy to mount yet have the range for 80-20M. The problem is on the low end of the cap range. His air cap won't go low enough for 80M without some kind of kludge with another cap.

BTW, stupid me: There's no need to move the stepper and cap inside the loop, which you probably shouldn't do anyway. The tubing leads can be bent slightly to shed water away from the leads' entry points into the box.

As I mentioned before, Al and I are making this a chapter in the new book and we are also writing an article on it, so we need to save some info for those. Let me talk to Al and see if we can give you the general dimensions of the loops and their spacing which would be enough to get going.

Jack, W8TEE

On Tuesday, June 25, 2019, 1:22:03 PM EDT, Art N4EZZ <n4ezz@...> wrote:


Jack,

When might we get some more details, dimensions, schematics, BOM, code?
If there is more information available I must have missed it. I would
like to start stocking up on parts.

In reference to Field Day you mentioned 40 and 20 meters, will this
design extend to 80?

Thanks, I do appreciate all that you and Al are doing to encourage
interest in building things for Ham radio.

If Al doesn't like the "luggable double double" why don't you call it
the "JackAl Mag Double" or even shorter "AJ Mag Double".

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
In any given circuit, the most expensive part will always sacrifice
itself to protect the fuse.

On 6/25/19 9:20 AM, Jack Purdum via Groups.Io wrote:
>  I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.
> Jack, W8TEE
>
>    On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote: 

>  Jack,
> Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
>



Re: Mag Loop for HOA's??

Jack, W8TEE
 

Yep. You can see the switches for step setting in the "red" rectangle on the side. eBay #123554326786 has it for $8, including shipping, from NJ.

Jack, W8TEE

On Tuesday, June 25, 2019, 1:52:45 PM EDT, SAM R BURNES via Groups.Io <sburnes@...> wrote:


Found this one on Amazon, is it the same model?

TB6600 4A 9-42V Stepper Motor Driver CNC Controller, Stepper Motor Driver Nema tb6600 Single Axes Two Phase Hybrid Stepper Motor for CNC





Sorry about the size, using a Mac and have no idea how to size it. 

Priced at about $13.00.

Sam
WY8V

On Jun 25, 2019, at 12:08 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:

We are using this stepper controller:

<dummyfile.0.part>
which can be purchased online for under $10. Our NEMA 17 stepper motor has 200 steps/revolution, or 1.8º. The table you see printed on the controller refers to switch settings that you can use to control the stepper. It allows you to "subdivide" that 1.8º by 32, which gives a really small nudge in the stepper. It works well.

Jack, W8TEE



On Tuesday, June 25, 2019, 12:38:00 PM EDT, Robert D. Bowers <n4fbz@...> wrote:


Unless they changed the design, I've got the parts of their loop (belongs to a friend that I haven't seen or heard from in years) back in storage.  It could be done, although you'd have to come up with changes to the mechanism between the motor and cap.  The motor on his was way too fast for his liking, and we'd talked about building an automated system, using steppers or a motor with a really big gear reduction.

I've got some old (semi) hard line that I've been thinking about making into a loop antenna.  The conductors (including external shielding) are solid copper, and we'd come up with an alternative form of tuning capacitor which should work well.  Problem is, I have too many things to deal with as it is and no income, so everything must be scrounged (and that usually takes a lot of time) - so it's on the back burner for the future.


On 6/25/19 11:20 AM, Jack Purdum via Groups.Io wrote:
I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.

Jack, W8TEE

On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote:


Jack,

Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
--
73 de RC.....KE6BGN

Re: Mag Loop for HOA's??

Art N4EZZ
 

Jack,

Thanks for the info. Loop dimensions and spacing would be enough to get
started. Along with that what VC range should I be looking for?

I eagerly anticipate the publishing of your book.

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
My email password has been hacked. That's the third time I've had to
rename the Dog.

On 6/25/19 12:00 PM, Jack Purdum via Groups.Io wrote:
 Art:
Al had a vacuum variable cap (VVC) with a different range and he was able to get it to work on 80M-20M, but the problem is setting the limit switches for a VVC. The pillow blocks and threads cost about $30 then add in the micro switches and the VVC. Al had an air cap that would work for 40-30-20M, so that's what we tried as it was less expensive. Also, the likelihood of someone having a usable air VC lying around unemployed is more likely that a VVC. I will be using a VVC on mine since I have a very small VVC I just picked up in Dayton that will be easy to mount yet have the range for 80-20M. The problem is on the low end of the cap range. His air cap won't go low enough for 80M without some kind of kludge with another cap.
BTW, stupid me: There's no need to move the stepper and cap inside the loop, which you probably shouldn't do anyway. The tubing leads can be bent slightly to shed water away from the leads' entry points into the box.
As I mentioned before, Al and I are making this a chapter in the new book and we are also writing an article on it, so we need to save some info for those. Let me talk to Al and see if we can give you the general dimensions of the loops and their spacing which would be enough to get going.

Jack, W8TEE

On Tuesday, June 25, 2019, 1:22:03 PM EDT, Art N4EZZ <n4ezz@...> wrote:

Jack,

When might we get some more details, dimensions, schematics, BOM, code?
If there is more information available I must have missed it. I would
like to start stocking up on parts.

In reference to Field Day you mentioned 40 and 20 meters, will this
design extend to 80?

Thanks, I do appreciate all that you and Al are doing to encourage
interest in building things for Ham radio.

If Al doesn't like the "luggable double double" why don't you call it
the "JackAl Mag Double" or even shorter "AJ Mag Double".

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
In any given circuit, the most expensive part will always sacrifice
itself to protect the fuse.

On 6/25/19 9:20 AM, Jack Purdum via Groups.Io wrote:
  I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.
Jack, W8TEE

    On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote: 
 
  Jack,
Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.






Re: Mag Loop for HOA's??

 

In an article I wrote for Elecraft in 2001 about miniature magnetic loop antennas, I portrayed a working model that covered 15m-60m but added 80m with the use of an optional 4-inch capacitor made from RG8 coax that would bridge across the main piston-capacitor. BTW, piston capacitors work well and can provide quite broad coverage. See below…

 

 

David A Posthuma, WD8PUO

1 (616) 283-7703

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Jack Purdum via Groups.Io
Sent: Tuesday, June 25, 2019 2:00 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Mag Loop for HOA's??

 

 Art:

 

Al had a vacuum variable cap (VVC) with a different range and he was able to get it to work on 80M-20M, but the problem is setting the limit switches for a VVC. The pillow blocks and threads cost about $30 then add in the micro switches and the VVC. Al had an air cap that would work for 40-30-20M, so that's what we tried as it was less expensive. Also, the likelihood of someone having a usable air VC lying around unemployed is more likely that a VVC. I will be using a VVC on mine since I have a very small VVC I just picked up in Dayton that will be easy to mount yet have the range for 80-20M. The problem is on the low end of the cap range. His air cap won't go low enough for 80M without some kind of kludge with another cap.

 

BTW, stupid me: There's no need to move the stepper and cap inside the loop, which you probably shouldn't do anyway. The tubing leads can be bent slightly to shed water away from the leads' entry points into the box.

 

As I mentioned before, Al and I are making this a chapter in the new book and we are also writing an article on it, so we need to save some info for those. Let me talk to Al and see if we can give you the general dimensions of the loops and their spacing which would be enough to get going.

 

Jack, W8TEE

 

On Tuesday, June 25, 2019, 1:22:03 PM EDT, Art N4EZZ <n4ezz@...> wrote:

 

 

Jack,

When might we get some more details, dimensions, schematics, BOM, code?
If there is more information available I must have missed it. I would
like to start stocking up on parts.

In reference to Field Day you mentioned 40 and 20 meters, will this
design extend to 80?

Thanks, I do appreciate all that you and Al are doing to encourage
interest in building things for Ham radio.

If Al doesn't like the "luggable double double" why don't you call it
the "JackAl Mag Double" or even shorter "AJ Mag Double".

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
In any given circuit, the most expensive part will always sacrifice
itself to protect the fuse.

On 6/25/19 9:20 AM, Jack Purdum via Groups.Io wrote:
>  I don't know much about their loop, but as I recall, everything is sealed inside a plastic housing. That would suggest a "No". Given that their loop costs around $400, it would be significantly cheaper to build the Double-Double. The main expenses for the loop are the copper tubing (figure 4 10' sections plus some fittings) and the AD9850 module (DDS). The PCB will cost under $10 and most parts are inexpensive except for the DDS. It's something to think about.
> Jack, W8TEE
>
>    On Tuesday, June 25, 2019, 11:01:12 AM EDT, ke6bgn@... <ke6bgn@...> wrote: 

>  Jack,
> Do you think this controller would be able to be used with the MFJ loops fairly easily? If so, this could be an excellent alternative to the manually driven setup that the factory setup provides.
>


Re: Mag Loop for HOA's??

Richard Spohn
 

Jack, thank you for all the great research, and I am looking forward
to your article and book on this antenna! BTW, I think the "Luggable
Double-Double" is a perfect title!

73 - Rich WB2GXM

On 6/24/19, Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
All:
We took Al's Double-Double mag loop:
for a spin at FD. We ran 100W on 20M and 40M. First, we were surprised how
well it performed for a "compromise" antenna. We worked 40M on Saturday and
worked KS to ME, WI to FL. We even managed to work pileups, often towards
the front of the pile. The stepper controller looks similar to this:

although this photo was taken before the software was finished. Two encoders
control the "target" frequency (e.g., 7199995) and the stepper motor, with
the SWR calculated using an AD9850 as a signal source. The final version
shows a 100-point plot of the SWR as you tune the cap to resonance on the
target frequency. The cap position and frequency are very close to linear,
so the final version will "fast step" to the target frequency and the
encoder can then fine tune from there. We can tune to 1.1:1.0 on 40-30-20M.
The display is a small 2.2" TFT display, but any SPI TFT using the ILI9341
driver could be used.
Quite honestly, Sunday wasn't as good. We concentrated on 20M and we were
expecting better performance. (The models say it should perform better on
20M.) We didn't hear as many stations as on 40M on Saturday, but we're not
sure if it was all antenna, band conditions, or a mixture of both. Al and I
will be writing an article on its construction in a little bit after some
testing that will give us some concrete numbers. We are devoting one chapter
in the new Projects book to its construction and a second chapter to the
stepper controller.

I will be trimming off the "spike" at the top for mine, which will allow it
to fit in my car trunk. (I want to call it the "Luggable Double-Double", but
Al doesn't like it.) Anyway, it will all be put into Open Source and we hope
that some HOA-bound hams might find it useful since its 3' diameter might
fit in an attic or somewhere else that the HOA considers acceptable.
BTW, I hope your club had as much fun at FD as we did...despite some rain.

Jack, W8TEEAl, AC8GY