locked Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m #transmit


Mark Bell
 

Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!

I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem. 

My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control. 

I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens. 

I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month. 

Any ideas what is happening? I am on the latest release of WSJT-X.


Michael Black
 

Common problem where specific bands have problems is due to RFI.

Please describe your grounding system.

You may find changing the USB plug to other side of the laptop helps.
Chokes on USB cables in particular help and chokes on ALL cables helps too (and I do mean ALL cables since any wire is an antenna).

Mike W9MDB




On Saturday, October 16, 2021, 09:50:29 AM CDT, Mark Bell via groups.io <mark.bell@...> wrote:


Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!

I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem. 

My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control. 

I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens. 

I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month. 

Any ideas what is happening? I am on the latest release of WSJT-X.




Joe Subich, W4TV
 

Any ideas what is happening? I am on the latest release of WSJT-X.
This is not a WSJT-X issue. *ANY* end-fed or off center fed antenna
is highly unbalanced which will turn the feedline into an unintentional
radial with RF currents on the *outside* of the shield. You will need
to *decouple* the feedline from the antenna by installing an effective
*COMMON MODE CHOKE* between the feed line and antenna and, perhaps,
installing a second *COMMON MODE CHOKE* where the feedline enters
your shack.

I recommend the information on common mode chokes at:
<http://k9yc.com/publish.htm>. In particular, "RFI, Ferrites, and
Common Mode Chokes For Hams" and "Transmitting Chokes For 160-10M"

73,

... Joe, W4TV


On 2021-10-16 10:47 AM, Mark Bell via groups.io wrote:
Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!
I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem.
My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control.
I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens.
I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month.
Any ideas what is happening? I am on the latest release of WSJT-X.


Mark Bell
 

Thanks again Joe. I've ordered some common mode chokes. The oddest thing about this is that it only happens with WSJT-X. I can do voice on 40m no problem with 1.2 SWR. It only happens when trying to do FT8 and it only started a month ago. Is there any explanation for why the sudden change or is it kind of like propogation -- up to the Gods. haha


Mark Bell
 

Hey there. My grounding system is as follows: copper wire from the lug nut of all equipment grounding lugs run individually to a bus bar(radio, tuner, power supply and amp). The bus bar is then run on a separate 12awg wire to earth ground rod outside driven 4 ft into earth. Antenna ground (at transformer outdoors) also runs to the same grounding rod using a 12awg copper wire. Also have a counterpoise wire running along the base of the house. I have lubricated all connections with NO-OX-ID (electrical grease) and all outdoor connections are sealed with silicon wrapping tape (almost puddy like) and electrical wire tape. I have also added bead choke rings to all wires, except the coax itself near both ends that make connections.


Mark Bell
 

Hey there. My grounding system is as follows: copper wire from the lug nut of all equipment grounding lugs run individually to a bus bar(radio, tuner, power supply and amp). The bus bar is then run on a separate 12awg wire to earth ground rod outside driven 4 ft into earth. Antenna ground (at transformer outdoors) also runs to the same grounding rod using a 12awg copper wire. Also have a counterpoise wire running along the base of the house. I have lubricated all connections with NO-OX-ID (electrical grease) and all outdoor connections are sealed with silicon wrapping tape (almost puddy like) and electrical wire tape. I have also added bead choke rings to all wires, except the coax itself near both ends that make connections.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android


From: main@WSJTX.groups.io <main@WSJTX.groups.io> on behalf of Michael Black via groups.io <mdblack98@...>
Sent: Saturday, October 16, 2021 9:56:34 AM
To: main@wsjtx.groups.io <main@wsjtx.groups.io>
Subject: Re: [WSJTX] Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m
 
[EXTERNAL SENDER]
Handle with care! DO NOT open attachments or click links from unknown senders or unexpected email! This email originated from outside the journeystn.org domain!

Common problem where specific bands have problems is due to RFI.

Please describe your grounding system.

You may find changing the USB plug to other side of the laptop helps.
Chokes on USB cables in particular help and chokes on ALL cables helps too (and I do mean ALL cables since any wire is an antenna).

Mike W9MDB




On Saturday, October 16, 2021, 09:50:29 AM CDT, Mark Bell via groups.io <mark.bell@...> wrote:


Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!

I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem. 

My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control. 

I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens. 

I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month. 

Any ideas what is happening? I am on the latest release of WSJT-X.



NOTICE: This email may contain confidential (including but not limited to) HIPAA-protected and/or privileged information intended only for specific, predetermined recipients. If you are not the intended recipient, you are hereby notified that any review, further dissemination, distribution or duplication of this communication IS STRICTLY FORBIDDEN. Please delete and/or destroy all copies of this message after notifying JICL IT of the error by reply email or by calling 615-890-4389.


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Mark Bell
 

Thank you Joe. I will look into this.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android


From: Mark Bell <mark.bell@...>
Sent: Saturday, October 16, 2021 10:29:39 AM
To: main@WSJTX.groups.io <main@WSJTX.groups.io>
Subject: Re: [WSJTX] Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m
 
Hey there. My grounding system is as follows: copper wire from the lug nut of all equipment grounding lugs run individually to a bus bar(radio, tuner, power supply and amp). The bus bar is then run on a separate 12awg wire to earth ground rod outside driven 4 ft into earth. Antenna ground (at transformer outdoors) also runs to the same grounding rod using a 12awg copper wire. Also have a counterpoise wire running along the base of the house. I have lubricated all connections with NO-OX-ID (electrical grease) and all outdoor connections are sealed with silicon wrapping tape (almost puddy like) and electrical wire tape. I have also added bead choke rings to all wires, except the coax itself near both ends that make connections.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android

From: main@WSJTX.groups.io <main@WSJTX.groups.io> on behalf of Michael Black via groups.io <mdblack98@...>
Sent: Saturday, October 16, 2021 9:56:34 AM
To: main@wsjtx.groups.io <main@wsjtx.groups.io>
Subject: Re: [WSJTX] Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m
 
[EXTERNAL SENDER]
Handle with care! DO NOT open attachments or click links from unknown senders or unexpected email! This email originated from outside the journeystn.org domain!

Common problem where specific bands have problems is due to RFI.

Please describe your grounding system.

You may find changing the USB plug to other side of the laptop helps.
Chokes on USB cables in particular help and chokes on ALL cables helps too (and I do mean ALL cables since any wire is an antenna).

Mike W9MDB




On Saturday, October 16, 2021, 09:50:29 AM CDT, Mark Bell via groups.io <mark.bell@...> wrote:


Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!

I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem. 

My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control. 

I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens. 

I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month. 

Any ideas what is happening? I am on the latest release of WSJT-X.



NOTICE: This email may contain confidential (including but not limited to) HIPAA-protected and/or privileged information intended only for specific, predetermined recipients. If you are not the intended recipient, you are hereby notified that any review, further dissemination, distribution or duplication of this communication IS STRICTLY FORBIDDEN. Please delete and/or destroy all copies of this message after notifying JICL IT of the error by reply email or by calling 615-890-4389.


Journeys in Community Living now uses Microsoft Information Protection and other traditional methods to secure its emails and documents. Please contact JICL IT if you have trouble viewing or opening a document sent from Journeys' employees.


Michael Black
 

Sounds like you don't  have your ground rod tied to the house ground rod.


Mike W9MDB 

On Saturday, October 16, 2021, 12:21:55 PM CDT, Mark Bell via groups.io <mark.bell@...> wrote:


Thank you Joe. I will look into this.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android

From: Mark Bell <mark.bell@...>
Sent: Saturday, October 16, 2021 10:29:39 AM
To: main@WSJTX.groups.io <main@WSJTX.groups.io>
Subject: Re: [WSJTX] Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m
 
Hey there. My grounding system is as follows: copper wire from the lug nut of all equipment grounding lugs run individually to a bus bar(radio, tuner, power supply and amp). The bus bar is then run on a separate 12awg wire to earth ground rod outside driven 4 ft into earth. Antenna ground (at transformer outdoors) also runs to the same grounding rod using a 12awg copper wire. Also have a counterpoise wire running along the base of the house. I have lubricated all connections with NO-OX-ID (electrical grease) and all outdoor connections are sealed with silicon wrapping tape (almost puddy like) and electrical wire tape. I have also added bead choke rings to all wires, except the coax itself near both ends that make connections.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android

From: main@WSJTX.groups.io <main@WSJTX.groups.io> on behalf of Michael Black via groups.io <mdblack98@...>
Sent: Saturday, October 16, 2021 9:56:34 AM
To: main@wsjtx.groups.io <main@wsjtx.groups.io>
Subject: Re: [WSJTX] Xeigu G90 // XPA125B amp // WSJT-X #transmit issue 40/30m
 
[EXTERNAL SENDER]
Handle with care! DO NOT open attachments or click links from unknown senders or unexpected email! This email originated from outside the journeystn.org domain!

Common problem where specific bands have problems is due to RFI.

Please describe your grounding system.

You may find changing the USB plug to other side of the laptop helps.
Chokes on USB cables in particular help and chokes on ALL cables helps too (and I do mean ALL cables since any wire is an antenna).

Mike W9MDB




On Saturday, October 16, 2021, 09:50:29 AM CDT, Mark Bell via groups.io <mark.bell@...> wrote:


Hello all. First off I'd like to thank the creators for the hours and hours of entertainment you've given me and others with the WSJT-X software! I love every aspect of this thing -- so seriously: Thank you!

I am writing today about an issue I am having with running FT8/FT4/other WSJT-X modes on 30m and 40m bands. This is an issue that just developed within the past few weeks for me, as previously I had been able to transmit on 30m and 40m no problem. 

My rig is the Xeigu G90 using the CE19 interface running into an external USB sound card on my HP Omen laptop running Windows 10, build 19043.1288 (21H1). I also use the XPA125B amplifier and tend to run FT8/FT4/others at around 35-50 watts depending upon band conditions. I use an Chameleon Emcomm III-B end-fed dipole with a MAT-TUNER mAT-125E external tuner. My SWR tends to hang around anywhere from 1.1 to 1.4 in normal conditions. I pair to WSJT-X using FLDigi and use CAT control. 

I still have no trouble operating on 10, 12, 15, 17, 20, 80 and 160, but over the past month I am unable to run more than 10w on 30 or 40 meters without the transmit immediately stopping on me. As soon as I start to increase power, I notice the SWR climbs to as high as 1.7. The amp is capable of running with SWR of up to 3.5 (know that isn't good for it though), but the transmit stops. I have also noticed power fluctuations of up to 70w when this happens. 

I have checked all connections and grounding and everything looks good. Antenna configuration is a half square on my roof and again this was working fine before this month. 

Any ideas what is happening? I am on the latest release of WSJT-X.



NOTICE: This email may contain confidential (including but not limited to) HIPAA-protected and/or privileged information intended only for specific, predetermined recipients. If you are not the intended recipient, you are hereby notified that any review, further dissemination, distribution or duplication of this communication IS STRICTLY FORBIDDEN. Please delete and/or destroy all copies of this message after notifying JICL IT of the error by reply email or by calling 615-890-4389.


Journeys in Community Living now uses Microsoft Information Protection and other traditional methods to secure its emails and documents. Please contact JICL IT if you have trouble viewing or opening a document sent from Journeys' employees.





d_ziolkowski
 

Mark- 

You are probably not sending audio through the PC when doing SSB. Also ground your PC as you do the other gear. 

Since this problem just developed, check for loose or corroded connecters and make sure a critter has not chewed your antenna lead. 

Also run a bond wire #6 minimum form your station ground rod to the ground rod at your power meter. It is required by National Electric code.  

Thanks Dan KC2STA


Joe Subich, W4TV
 

The oddest thing about this is that it only happens with WSJT-X. I can do voice on 40m no problem with 1.2 SWR.
FT8 (and other WSJTX modes) are FSK (continuous power) modes; SSB is
not. FT8 will generate as much as 10x as much RF voltage on the
shield of the feedline as SSB. It is the magnitude of that voltage
that causes problems with the USB ports of computers/rigs.

73,

... Joe, W4TV


On 2021-10-16 12:15 PM, Mark Bell via groups.io wrote:
Thanks again Joe. I've ordered some common mode chokes. The oddest thing about this is that it only happens with WSJT-X. I can do voice on 40m no problem with 1.2 SWR. It only happens when trying to do FT8 and it only started a month ago. Is there any explanation for why the sudden change or is it kind of like propogation -- up to the Gods. haha


Jim Brown
 

On 10/16/2021 9:15 AM, Mark Bell via groups.io wrote:
I've ordered some common mode chokes.
My Choke Cookbook, the link for which W4TV posted, describes FAR better chokes than you can buy. I know of no commercial products worth their cost.

73, Jim K9YC


Jim Brown
 

On 10/16/2021 9:25 AM, Mark Bell via groups.io wrote:
The bus bar is then run on a separate 12awg wire to earth ground rod outside driven 4 ft into earth. Antenna ground (at transformer outdoors) also runs to the same grounding rod using a 12awg copper wire. Also have a counterpoise wire running along the base of the house. I have lubricated all connections with NO-OX-ID (electrical grease) and all outdoor connections are sealed with silicon wrapping tape (almost puddy like) and electrical wire tape. I have also added bead choke rings to all wires, except the coax itself near both ends that make connections.
I see nothing here saying that you have these grounds bonded to others in your home, like power, telco, and CATV, all of which are a must (required by LAW!). And I see nothing about everything in your station, including the computer, having their chassis bonded together. And NO grounding or bonding wires should have ferrite beads on them.

Buy and study N0AX's ARRL book on Grounding and Bonding, to which I contributed, and/or the slides for my tutorial on the topic.

http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC


Mark Bell
 

Jim: I appreciate the suggestion and will give grounding and bonding much more due diligence. I admit I am nowhere near an expert on ham radio -- only got my general in May and my technician in March -- but you made a lot of assumptions (partly because I wasn't very clear in my post) in your reply. I have ferrite chokes on all of my USB cables and such that connect the computer, radio and Xeigu's breakout box (CE-19 interface). I did not have any ferrite on the coax running to the antenna, though -- that was what I was saying. All of my equipment in the shack is grounded with an individual wire to a bus bar inside the shack. It has another ground wire that runs to the grounding rod outside, which is bonded with my house's electrical system. My antenna is grounded to the same grounding rod. 

Now with that out of the way, I did a test by taking all of the extra coax I had curled up behind my bench in the shack (my coax cable is 75 ft total in length, of which about 40 percent was behind my desk wrapped up in a loose circle) and wrapped it tightly around some spare PVC pipe I had laying around from when I ran my ground and coax through the wall. This corrected the problem, so the guys talking about the RFI choke were on the right track with this. 

Here is the photo of my fix, which has gotten me back on the air on 40m and 30m:


Mark Bell
 

All of my equipment in the shack is grounded with an individual wire to a bus bar inside the shack.
Not being clear here again. Each device has its own wire 12awg wire. Nothing is daisy-chained. I read that Daisy Chaining is a sure way to cause grounding issues.

Anyway. I appreciate everyone's help/replies and consider this solved as it is still working as expected still as of this morning, though I may still add an actual choke instead of my homemade one and eventually shorten this Coax feed -- 75 ft is just too much coax I think and I've read long wire runs can cause problems in themselves. Originally -- before I had the Chameleon end-fed -- I had a different OCFD in my attic and 75ft was required to make the trip. I went back through the Chameleon's manual and found that they recommend a 50 ft run, as well as possibly a choke depending on the installation. 

Speaking of which: One more question about the choke itself. If I buy one from a manufacturer, is the manual going to tell me exactly where to install it? I've seen some recommending closer to the feed point of the antenna, others at the entrance of the shack and some near the transmitter? I've seen people recommending it two different ways. Some I read even said install one choke near the feed point and another near the radio. 


Jim Brown
 

On 10/17/2021 6:09 AM, Mark Bell via groups.io wrote:
If I buy one from a manufacturer, is the manual going to tell me exactly where to install it? I've seen some recommending closer to the feed point of the antenna, others at the entrance of the shack and some near the transmitter? I've seen people recommending it two different ways. Some I read even said install one choke near the feed point and another near the radio.
NEVER buy a choke. ALWAYS build it from my Choke Cookbook. First, the cookbook. http://k9yc.com/2018Cookbook.pdf

Slides for a talk a did for Pacificon on Friday.

k9yc.com/2018Cookbook-Pacificon2021.pdf

First choke ALWAYS at the feedpoint (up in the air, or at the base of a vertical).

If a choke at the shack helps, you have SERIOUS problems with bonding and grounding. Study N0AX's ARRL Book on the topic, to which I contributed, and/or study the slides for talks I've done at Pacificon, Visalia, and to several ham clubs. The second edition was just released.

http://k9yc.com/GroundingAndAudio.pdf

Note that a few specifics of power system bonding are different outside NA, but Mother Nature (the Laws of Physics) doesn't respect political borders, building codes, or trade unions. Both my work and Ward's are specifically written for NA, but there are docs on my website that are international in scope, and in consultancy with a colleague in the UK, with whom I have long served on the Standards Committee of the Audio Engineering Society. k9yc.com/publish/htm

73, Jim K9YC


Michael Black
 

On Monday, October 18, 2021, 04:30:05 AM CDT, Jim Brown <k9yc@...> wrote:


On 10/17/2021 6:09 AM, Mark Bell via groups.io wrote:

> If I buy one from a manufacturer, is the manual going to tell me exactly
> where to install it? I've seen some recommending closer to the feed
> point of the antenna, others at the entrance of the shack and some near
> the transmitter? I've seen people recommending it two different ways.
> Some I read even said install one choke near the feed point and another
> near the radio.


NEVER buy a choke. ALWAYS build it from my Choke Cookbook. First, the
cookbook. http://k9yc.com/2018Cookbook.pdf

Slides for a talk a did for Pacificon on Friday.

k9yc.com/2018Cookbook-Pacificon2021.pdf

First choke ALWAYS at the feedpoint (up in the air, or at the base of a
vertical).

If a choke at the shack helps, you have SERIOUS problems with bonding
and grounding. Study N0AX's ARRL Book on the topic, to which I
contributed, and/or study the slides for talks I've done at Pacificon,
Visalia, and to several ham clubs. The second edition was just released.

http://k9yc.com/GroundingAndAudio.pdf

Note that a few specifics of power system bonding are different outside
NA, but Mother Nature (the Laws of Physics) doesn't respect political
borders, building codes, or trade unions. Both my work and Ward's are
specifically written for NA, but there are docs on my website that are
international in scope, and in consultancy with a colleague in the UK,
with whom I have long served on the Standards Committee of the Audio
Engineering Society. k9yc.com/publish/htm

73, Jim K9YC









Jim Brown
 

Negative. It's a string of beads. #31 is the right material for HF, but without multiple turns, it's primarily inductive at HF. It's addressed directly in this slide deck.

http://k9yc.com/CoaxChokesPPT.pdf

73, Jim K9YC