Topics

HF Magnetic Loop and Pacemaker


Dan Reynolds
 

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO


John - KK4ITX
 

I use the MFJ-9232 QRP Pocket Loop tuner and find it a useful setup to eliminate the local noise.  There are several YouTube videos showing good results but beware...... they were made when there were sun spots.  I had great fun rigging up the expansion arrangement to allow for various lengths of wire.  To get a broader bandwidth I used trailer hookup wire, seems to work better than the wire that came with it.

The supports are driveway markers and I really lucked out at a Flea Market with the $4.00 heavy duty tri-pod.  I have attached a picture of the assembled unit if anyone is interested I have more and some additional hints and details to offer.

As for use with a pacemaker ?  You will know if it is bothering you or anyone else I believe.  When I tune up I am listening (RX) or using my Sark 100 so there’s no large amount of RF present....... Operating (TX) one would be several feet away so at 5w I doubt that you would be affected but just go at it slow (1-2w) and see what happens.

Enjoy,

John
KK4ITX 
image1.jpeg

Visit:  www.zaarc.org.   👁

On Jan 29, 2020, at 22:18, Dan Reynolds <on30ng@...> wrote:

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO


John Lonigro
 

Start with 1 Watt, then go with 2 Watts, etc.  If you die, back down a Watt (hi).

John, AA0VE

On 1/30/20 9:24 AM, John - KK4ITX via Groups.Io wrote:
I use the MFJ-9232 QRP Pocket Loop tuner and find it a useful setup to eliminate the local noise.  There are several YouTube videos showing good results but beware...... they were made when there were sun spots.  I had great fun rigging up the expansion arrangement to allow for various lengths of wire.  To get a broader bandwidth I used trailer hookup wire, seems to work better than the wire that came with it.

The supports are driveway markers and I really lucked out at a Flea Market with the $4.00 heavy duty tri-pod.  I have attached a picture of the assembled unit if anyone is interested I have more and some additional hints and details to offer.

As for use with a pacemaker ?  You will know if it is bothering you or anyone else I believe.  When I tune up I am listening (RX) or using my Sark 100 so there’s no large amount of RF present....... Operating (TX) one would be several feet away so at 5w I doubt that you would be affected but just go at it slow (1-2w) and see what happens.

Enjoy,

John
KK4ITX 
image1.jpeg

Visit:  www.zaarc.org.   👁

On Jan 29, 2020, at 22:18, Dan Reynolds <on30ng@...> wrote:

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO


Jim Sheldon
 

Morbidly funny John, but really, a good point.  Some info on at least one brand of pacemaker (the one I have).

I too have a pacemaker.  I often run 500 watts and one end of the 160-80-40 meter antenna runs right over the shack, about 3 feet above the house roof.  My pacemaker is from "Boston Scientific", has bluetooth connectivity to a remote monitor that lets my cardiologist know immediately if something goes wrong with either ME or the pacemaker.  I'm on the air almost daily for at least one QRO contact on 40 meters and in over 12 years, have had no RF episodes with the pacemaker.

My Boston Scientific rep said the main thing to avoid is high magnetic fields as a coded magnetic signal is used to trigger diagnostic mode in their pacemakers so a Mag Loop might be a different ball game entirely.  I don't have one here but then I have a 40' telescoping vertical that collapses down to 3 feet for my portable operations when I even go portable anymore - LOL.

That being said, I agree with the need to use CAUTION when operating close to radiated fields of any kind when one has a pacemaker implant as I'm sure the manufacturers all use different RF and Magnetic exposure standards from each other and results will surely vary.  Best to err on the side of safety.


Jim, W0EB

------ Original Message ------
From: "John Lonigro" <jonigro@...>
Sent: 1/30/2020 9:42:39 AM
Subject: Re: [4SQRP] HF Magnetic Loop and Pacemaker

Start with 1 Watt, then go with 2 Watts, etc.  If you die, back down a Watt (hi).

John, AA0VE

On 1/30/20 9:24 AM, John - KK4ITX via Groups.Io wrote:
I use the MFJ-9232 QRP Pocket Loop tuner and find it a useful setup to eliminate the local noise.  There are several YouTube videos showing good results but beware...... they were made when there were sun spots.  I had great fun rigging up the expansion arrangement to allow for various lengths of wire.  To get a broader bandwidth I used trailer hookup wire, seems to work better than the wire that came with it.

The supports are driveway markers and I really lucked out at a Flea Market with the $4.00 heavy duty tri-pod.  I have attached a picture of the assembled unit if anyone is interested I have more and some additional hints and details to offer.

As for use with a pacemaker ?  You will know if it is bothering you or anyone else I believe.  When I tune up I am listening (RX) or using my Sark 100 so there’s no large amount of RF present....... Operating (TX) one would be several feet away so at 5w I doubt that you would be affected but just go at it slow (1-2w) and see what happens.

Enjoy,

John
KK4ITX 
image1.jpeg

Visit:  www.zaarc.org.   👁

On Jan 29, 2020, at 22:18, Dan Reynolds <on30ng@...> wrote:

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO


Don, W9EBK
 

Dan,
www.66pacific.com is the go-to source for working out how to make HF magnetic loop antennas. 
Don,W9EBK 

On Wed, Jan 29, 2020, 9:18 PM Dan Reynolds <on30ng@...> wrote:
I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO


John Lonigro
 

I'm sorry.  I didn't intend to be morbid.  My point was that, to be safe, the person with a pacemaker should check with the manufacturer of his device as well as with his doctor.

Reminder: The February Second Sunday Sprint is a little more than a week away.

72,

John, AA0VE

On 1/30/20 10:00 AM, Jim Sheldon wrote:
Morbidly funny John, but really, a good point.  Some info on at least one brand of pacemaker (the one I have).

I too have a pacemaker.  I often run 500 watts and one end of the 160-80-40 meter antenna runs right over the shack, about 3 feet above the house roof.  My pacemaker is from "Boston Scientific", has bluetooth connectivity to a remote monitor that lets my cardiologist know immediately if something goes wrong with either ME or the pacemaker.  I'm on the air almost daily for at least one QRO contact on 40 meters and in over 12 years, have had no RF episodes with the pacemaker.

My Boston Scientific rep said the main thing to avoid is high magnetic fields as a coded magnetic signal is used to trigger diagnostic mode in their pacemakers so a Mag Loop might be a different ball game entirely.  I don't have one here but then I have a 40' telescoping vertical that collapses down to 3 feet for my portable operations when I even go portable anymore - LOL.

That being said, I agree with the need to use CAUTION when operating close to radiated fields of any kind when one has a pacemaker implant as I'm sure the manufacturers all use different RF and Magnetic exposure standards from each other and results will surely vary.  Best to err on the side of safety.


Jim, W0EB

------ Original Message ------
From: "John Lonigro" <jonigro@...>
Sent: 1/30/2020 9:42:39 AM
Subject: Re: [4SQRP] HF Magnetic Loop and Pacemaker

Start with 1 Watt, then go with 2 Watts, etc.  If you die, back down a Watt (hi).

John, AA0VE

On 1/30/20 9:24 AM, John - KK4ITX via Groups.Io wrote:
I use the MFJ-9232 QRP Pocket Loop tuner and find it a useful setup to eliminate the local noise.  There are several YouTube videos showing good results but beware...... they were made when there were sun spots.  I had great fun rigging up the expansion arrangement to allow for various lengths of wire.  To get a broader bandwidth I used trailer hookup wire, seems to work better than the wire that came with it.

The supports are driveway markers and I really lucked out at a Flea Market with the $4.00 heavy duty tri-pod.  I have attached a picture of the assembled unit if anyone is interested I have more and some additional hints and details to offer.

As for use with a pacemaker ?  You will know if it is bothering you or anyone else I believe.  When I tune up I am listening (RX) or using my Sark 100 so there’s no large amount of RF present....... Operating (TX) one would be several feet away so at 5w I doubt that you would be affected but just go at it slow (1-2w) and see what happens.

Enjoy,

John
KK4ITX 
image1.jpeg

Visit:  www.zaarc.org.   👁

On Jan 29, 2020, at 22:18, Dan Reynolds <on30ng@...> wrote:

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO



Jim Sheldon
 

Hey John, I was actually just joking with you, but your point even though humorous was well spoken.  Thanks for thinking of those of us who are getting older and have such accessories as pacemakers keeping us active.  No need to apologize.  

Jim - W0EB

------ Original Message ------
From: "John Lonigro" <jonigro@...>
Sent: 1/30/2020 12:50:47 PM
Subject: Re: [4SQRP] HF Magnetic Loop and Pacemaker

I'm sorry.  I didn't intend to be morbid.  My point was that, to be safe, the person with a pacemaker should check with the manufacturer of his device as well as with his doctor.

Reminder: The February Second Sunday Sprint is a little more than a week away.

72,

John, AA0VE

On 1/30/20 10:00 AM, Jim Sheldon wrote:
Morbidly funny John, but really, a good point.  Some info on at least one brand of pacemaker (the one I have).

I too have a pacemaker.  I often run 500 watts and one end of the 160-80-40 meter antenna runs right over the shack, about 3 feet above the house roof.  My pacemaker is from "Boston Scientific", has bluetooth connectivity to a remote monitor that lets my cardiologist know immediately if something goes wrong with either ME or the pacemaker.  I'm on the air almost daily for at least one QRO contact on 40 meters and in over 12 years, have had no RF episodes with the pacemaker.

My Boston Scientific rep said the main thing to avoid is high magnetic fields as a coded magnetic signal is used to trigger diagnostic mode in their pacemakers so a Mag Loop might be a different ball game entirely.  I don't have one here but then I have a 40' telescoping vertical that collapses down to 3 feet for my portable operations when I even go portable anymore - LOL.

That being said, I agree with the need to use CAUTION when operating close to radiated fields of any kind when one has a pacemaker implant as I'm sure the manufacturers all use different RF and Magnetic exposure standards from each other and results will surely vary.  Best to err on the side of safety.


Jim, W0EB

------ Original Message ------
From: "John Lonigro" <jonigro@...>
Sent: 1/30/2020 9:42:39 AM
Subject: Re: [4SQRP] HF Magnetic Loop and Pacemaker

Start with 1 Watt, then go with 2 Watts, etc.  If you die, back down a Watt (hi).

John, AA0VE

On 1/30/20 9:24 AM, John - KK4ITX via Groups.Io wrote:
I use the MFJ-9232 QRP Pocket Loop tuner and find it a useful setup to eliminate the local noise.  There are several YouTube videos showing good results but beware...... they were made when there were sun spots.  I had great fun rigging up the expansion arrangement to allow for various lengths of wire.  To get a broader bandwidth I used trailer hookup wire, seems to work better than the wire that came with it.

The supports are driveway markers and I really lucked out at a Flea Market with the $4.00 heavy duty tri-pod.  I have attached a picture of the assembled unit if anyone is interested I have more and some additional hints and details to offer.

As for use with a pacemaker ?  You will know if it is bothering you or anyone else I believe.  When I tune up I am listening (RX) or using my Sark 100 so there’s no large amount of RF present....... Operating (TX) one would be several feet away so at 5w I doubt that you would be affected but just go at it slow (1-2w) and see what happens.

Enjoy,

John
KK4ITX 
image1.jpeg

Visit:  www.zaarc.org.   👁

On Jan 29, 2020, at 22:18, Dan Reynolds <on30ng@...> wrote:

I have access to some hardline and I'm thinking about making  a transmitting loop. I know there was a design out there that used an Arudino to tune the loop at frequency changes... 
Anybody have some decent designs - I do not want to design it myself. I'm not too proud to borrow someone else's work. 

Also, does anyone know about any problems with a transmitting mag loop and a pacemaker (QRP levels only). 

--
Dan Reynolds -- KB9JLO



Dan Reynolds
 

Yeah, I knew you guys were joking. And I have spoken with the MFR. The major "danger" is not that it will fail but more that the electrical "interference" will screw up the programming. I'm on my 2nd one (atrial fib) and actually just about due for my 3rd. I'm sure they have backups but I don't want to mess with the programming. It works well now. And magnetic fields and sparking/arcing are the things most worrisome. For example if you do arc weld you're never to put the leads over your shoulder - keep them as far away from your chest as you can. And with a running car - you shouldn't get your hands near the spark plug leads. I don't weld anymore. It was only a hobby thing at best. Working on cars I obey that rule to max. 

I know the suggestion was to talk to the MFR but I can't imagine many of them understanding what a transmitting mag loop antenna is. I have a Medtronics device, single lead. I am 100% paced and in the procedure they ablated the AV mode to "disconnect" the top from the bottom parts of the heart.  I had mine implanted before they had come up with better alternative treatments for a-fib. A pacemaker is not very common for that now. Other than those few precautions I would say I'm better than new! 
--
Dan Reynolds -- KB9JLO


Dan Reynolds
 

On Thu, Jan 30, 2020 at 09:24 AM, John - KK4ITX wrote:
MFJ-9232 QRP Pocket Loop tuner
That's pretty interesting - have you had good luck with it? And yes, I would have to tune it with an analyzer - LOL. No way I'd want to be close enough to touch those knobs with real RF going through it.  I'll bet it would work well with a loop made of hard line. Heck I could make one for each band almost. 

Now an arduino controlling that would be pretty darn cool. 
 
--
Dan Reynolds -- KB9JLO
<><


John - KK4ITX
 

So far I have only put it through the receiving paces.  As far as I know the only time any appreciable RF would be present is when transmitting.  You coarse and then fine tune by ear, not by keying up and transmitting.  I only use the analyzer for checking as my hearing is very directional.

I took it out yesterday afternoon for an hour or so at a RF quiet park and was quite pleased with the reception.

MFJ has details and a video to explain how it works on their website.  Also QST had an article a couple of months ago dealing with making a neat loop using 450 ladder line...... you might give that a read.  I plan to try it also.

John
KK4ITX 

Visit:  www.zaarc.org.   👁

On Jan 31, 2020, at 11:30, Dan Reynolds <on30ng@...> wrote:

On Thu, Jan 30, 2020 at 09:24 AM, John - KK4ITX wrote:
MFJ-9232 QRP Pocket Loop tuner
That's pretty interesting - have you had good luck with it? And yes, I would have to tune it with an analyzer - LOL. No way I'd want to be close enough to touch those knobs with real RF going through it.  I'll bet it would work well with a loop made of hard line. Heck I could make one for each band almost. 

Now an arduino controlling that would be pretty darn cool. 
 
--
Dan Reynolds -- KB9JLO
<><


John - KK4ITX
 

Here’s a photo of a spreadsheet that I made up last October for making the QST Loop.  

image1.png

Visit:  www.zaarc.org.   👁

On Jan 31, 2020, at 13:02, John - KK4ITX via Groups.Io <jleahy00@...> wrote:

So far I have only put it through the receiving paces.  As far as I know the only time any appreciable RF would be present is when transmitting.  You coarse and then fine tune by ear, not by keying up and transmitting.  I only use the analyzer for checking as my hearing is very directional.

I took it out yesterday afternoon for an hour or so at a RF quiet park and was quite pleased with the reception.

MFJ has details and a video to explain how it works on their website.  Also QST had an article a couple of months ago dealing with making a neat loop using 450 ladder line...... you might give that a read.  I plan to try it also.

John
KK4ITX 

Visit:  www.zaarc.org.   👁

On Jan 31, 2020, at 11:30, Dan Reynolds <on30ng@...> wrote:

On Thu, Jan 30, 2020 at 09:24 AM, John - KK4ITX wrote:
MFJ-9232 QRP Pocket Loop tuner
That's pretty interesting - have you had good luck with it? And yes, I would have to tune it with an analyzer - LOL. No way I'd want to be close enough to touch those knobs with real RF going through it.  I'll bet it would work well with a loop made of hard line. Heck I could make one for each band almost. 

Now an arduino controlling that would be pretty darn cool. 
 
--
Dan Reynolds -- KB9JLO
<><


John
 

please send me a copy or upload into the groups?
John VE3IPS

Ham Radio is a lifestyle not a Hobby!
Take the radio outside and operate from the Field




On Fri, Jan 31, 2020 at 1:29 PM John - KK4ITX via Groups.Io <jleahy00=yahoo.com@groups.io> wrote:
Here’s a photo of a spreadsheet that I made up last October for making the QST Loop.  

image1.png

Visit:  www.zaarc.org.   👁

On Jan 31, 2020, at 13:02, John - KK4ITX via Groups.Io <jleahy00@...> wrote:

So far I have only put it through the receiving paces.  As far as I know the only time any appreciable RF would be present is when transmitting.  You coarse and then fine tune by ear, not by keying up and transmitting.  I only use the analyzer for checking as my hearing is very directional.

I took it out yesterday afternoon for an hour or so at a RF quiet park and was quite pleased with the reception.

MFJ has details and a video to explain how it works on their website.  Also QST had an article a couple of months ago dealing with making a neat loop using 450 ladder line...... you might give that a read.  I plan to try it also.

John
KK4ITX 

Visit:  www.zaarc.org.   👁

On Jan 31, 2020, at 11:30, Dan Reynolds <on30ng@...> wrote:

On Thu, Jan 30, 2020 at 09:24 AM, John - KK4ITX wrote:
MFJ-9232 QRP Pocket Loop tuner
That's pretty interesting - have you had good luck with it? And yes, I would have to tune it with an analyzer - LOL. No way I'd want to be close enough to touch those knobs with real RF going through it.  I'll bet it would work well with a loop made of hard line. Heck I could make one for each band almost. 

Now an arduino controlling that would be pretty darn cool. 
 
--
Dan Reynolds -- KB9JLO
<><


W4OED
 

Although it is true that tuning a loop antenna while transmitting is bad for your help, it is also true that you may very well be able to tune the antenna in reception mode by listening to the noise coming from the speaker: the higher the noise level becomes the closer to the receiving frequency the antenna is.
I saw a modification for a loop antenna that used two pieces of garden hose set around the knobs that seemed to work despite of being cumbersome to setup.

Oscar
W4OED


WB9BKJ <dmason@...>
 

Check out the MFJ-212.