Can we work to improve this?

Hi Eric, This looks really cool. I was thinking of doing something like this myself, and would like to try to make a version that I could use as my primary antenna. I think there are a number of areas that would need to be modified so that it would survive outdoors and be reliable. I'd like to work on that. I'm a electrical/software engineer by profession, but do not have training in mechanical design. Could you reply with your email address, and I can reach out to you, and see if there are things I could work on.

Thanks, Dave Hempstead WA1RCT

Dear Dave:

Thanks for the note!

I would be happy to help in any way I can to improve the antenna system. I enjoy the engineering stuff a lot!

I have been interested in antenna physics since high school. Having been trained as a broadcast engineer, I was always somewhat surprised by the ”If your tuner can fix the SWR - it’s good enough” attitude that a lot of HAM’s seem to operate with. (In AM radio, we designed the antenna to be near-perfect, and then designed everything else for the best efficiency.)

The project on GitHUB was at first a platform to experiment with the physics, and mutated into a useful antenna for a friend.

I have found the prototype durable enough for temporary use like field days and similar operation. (3 guyed 41 foot poles) The housing is PETG rather than PLA, I had intended to paint it if needed.

The small size is a compromise. If I were to build another for long term use on a good tower, I’d switch to a better (bigger?) motor.

Larger diameter spools would hold thicker wire, but would require more torque than NEMA 17 (which I already had) would provide.
Wide spools would hold thicker wire, but would “wind” inconsistently resulting in tangles.

I tried a lot of iterations of various parts, and came up with the compromise that works well in my environment.

I considered using outdoor rated PVC pipe or similar for the housing with add-on external brush-holder thingies instead of printing the whole thing.
I tried copper alloy “brushes” with good success (Copying SteppIR), but found the replaceable carbon brushes to last well.
From an electrical engineering point of view,  the important part is to have non-conducting spools - I don’t think a metal case would be out fo the question.
Also tried belt drive reduction for more torque, but found it too complicated and hard to keep adjusted (Belts were hard to find the right size).
I considered an ESP32 based system, as well as ditching the WIFI altogether and just making a USB connected controller -
    The WIFI Stepper product just made “the first try” easier since I had no experience with stepper motors.

I am currently working on building a static web page with a tiny bit of Javascript in place of NODE-RED and the required server.
(If you stick with the WIFI stepper product, an HTTP “get” statement is all that you need to send in order to send commands.)

I’d be interested in what you think.

Eric.

AD0MZ

@.***

On Jan 5, 2022, at 4:05 PM, WA1RCT @.***> wrote:

Hi Eric, This looks really cool. I was thinking of doing something like this myself, and would like to try to make a version that I could use as my primary antenna. I think there are a number of areas that would need to be modified so that it would survive outdoors and be reliable. I'd like to work on that. I'm a electrical/software engineer by profession, but do not have training in mechanical design. Could you reply with your email address, and I can reach out to you, and see if there are things I could work on.

Thanks, Dave Hempstead WA1RCT

— Reply to this email directly, view it on GitHub https://github.com/AD0MZ/All-Band-Adjustable-Dipole/issues/2, or unsubscribe https://github.com/notifications/unsubscribe-auth/AS25NSC3K6LTJS5VICSUYFDUUS6A5ANCNFSM5LK6EP7Q. Triage notifications on the go with GitHub Mobile for iOS https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675 or Android https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub. You are receiving this because you are subscribed to this thread.

HI Eric, Thank you so much for the quick reply. Here are my thoughts. I currently have a folded dipole which works 'ok' from 160M to 10M. I've been playing with auto tuners (built up a ATU-100 model recently), but I agree with you that having a resonant antenna is the best starting point. My personal goal would be to try to develop an antenna for my setup that will work well across that entire range. I have an IC-7300 rig, and run digital often, so I would want the antenna to handle 100w-200w without any issues. I have fellow hams who might be interested, and they run 1kw+. My current dipole is 140 feet, suspended from trees, with an additional support rope at the center point (all support ropes are on pulleys for easy raising and lowering). So I believe I could put some weight at the center (even without a tower). I was thinking of a setup similar to your prototype, and then googled it and found you. I've reached out to a friend that I previously worked with. He is a highly skilled mechanical engineer who has spent his career designing the mechanical parts of medical products, including some that used small precision motors and cables. If he would be willing to provide any component selection advice or provide any guidance, I think this would help me alot. For me the mechanical aspects would be the biggest challenge. For the electrical and software, I have tons of ideas for automating the system. I'm thinking of getting a raspberry pi to run it (and I think it can also run your software). I am confident I could automate this to work any way I'd like.(I prefer fully automatic systems, and usually the best solution is closed loop)

From what I've seen on your website, here are my thoughts: 1) the cable/wire will need to be enclosed to work in New England (ice and snow). My thought is to have a rope running the entire length of the antenna, and hanging a flexible tube under it, and the wire+rope/cable will run completely inside the tube. At each end there would be a pulley on a spring (inside the tube, I've found some very small pulleys, check out Harken) and the far ends of the tube would be sealed. THen where it meets the center unit, the tubes would have to be attached weathertight to the unit. 2) I think you bring up very good points about the motor and the spools. I don't know the best radius to consider, but I'd have to worry about life of the wire and the rope/cable bending so often. Have you looked into that? Also have you looked into corrosion on the cable, or just having the copper build up surface resistance as it weathers? This would create resistance and then when coiled it wouldn't have the low resistance we need. Have you considered tinned wire? Does that change the flexibility of the cable? 3) I was thinking of using small diameter dacron or dyneema rope, and then I found some flexible wire (almost like grounding braid). For high power, we would need to consider heavier gauge, maybe even 12 gauge. That will get heavy, and be much tougher to run on the spool. 4) I like your spools. I was thinking of using a bolt at the center as the axle, and attaching the wire to the bolt (I had assumed 2 separate wheels, each on a separate axle), and then the brush simply touches a bolt head that rotates, rather than touches a moving wire. But this would require 2 separate axles (or at least an insulator between the spool axle. 5) I don't know much about the strength of stepper motors, or how much force you need to turn the spools. 6) I do have another friend who has a 3D printer, so I could ask him to print up some parts for me.

Your thoughts? Dave WA1RCT

On Wed, Jan 5, 2022 at 8:15 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note!

I would be happy to help in any way I can to improve the antenna system. I enjoy the engineering stuff a lot!

I have been interested in antenna physics since high school. Having been trained as a broadcast engineer, I was always somewhat surprised by the ”If your tuner can fix the SWR - it’s good enough” attitude that a lot of HAM’s seem to operate with. (In AM radio, we designed the antenna to be near-perfect, and then designed everything else for the best efficiency.)

The project on GitHUB was at first a platform to experiment with the physics, and mutated into a useful antenna for a friend.

I have found the prototype durable enough for temporary use like field days and similar operation. (3 guyed 41 foot poles) The housing is PETG rather than PLA, I had intended to paint it if needed.

The small size is a compromise. If I were to build another for long term use on a good tower, I’d switch to a better (bigger?) motor.

Larger diameter spools would hold thicker wire, but would require more torque than NEMA 17 (which I already had) would provide.

Wide spools would hold thicker wire, but would “wind” inconsistently resulting in tangles.

I tried a lot of iterations of various parts, and came up with the compromise that works well in my environment.

I considered using outdoor rated PVC pipe or similar for the housing with add-on external brush-holder thingies instead of printing the whole thing. I tried copper alloy “brushes” with good success (Copying SteppIR), but found the replaceable carbon brushes to last well. From an electrical engineering point of view, the important part is to have non-conducting spools - I don’t think a metal case would be out fo the question. Also tried belt drive reduction for more torque, but found it too complicated and hard to keep adjusted (Belts were hard to find the right size). I considered an ESP32 based system, as well as ditching the WIFI altogether and just making a USB connected controller - The WIFI Stepper product just made “the first try” easier since I had no experience with stepper motors.

I am currently working on building a static web page with a tiny bit of Javascript in place of NODE-RED and the required server. (If you stick with the WIFI stepper product, an HTTP “get” statement is all that you need to send in order to send commands.)

I’d be interested in what you think.

Eric.

AD0MZ

@.***

On Jan 5, 2022, at 4:05 PM, WA1RCT @.***> wrote:

Hi Eric, This looks really cool. I was thinking of doing something like this myself, and would like to try to make a version that I could use as my primary antenna. I think there are a number of areas that would need to be modified so that it would survive outdoors and be reliable. I'd like to work on that. I'm a electrical/software engineer by profession, but do not have training in mechanical design. Could you reply with your email address, and I can reach out to you, and see if there are things I could work on.

Thanks, Dave Hempstead WA1RCT

— Reply to this email directly, view it on GitHub < https://github.com/AD0MZ/All-Band-Adjustable-Dipole/issues/2>, or unsubscribe < https://github.com/notifications/unsubscribe-auth/AS25NSC3K6LTJS5VICSUYFDUUS6A5ANCNFSM5LK6EP7Q . Triage notifications on the go with GitHub Mobile for iOS < https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android < https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

You are receiving this because you are subscribed to this thread.

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You are receiving this because you authored the thread.Message ID: @.***>

Dear Dave:

Thanks for the note.

Like you, here in Minnesota - I worried about ice a bit.
I found that if I retracted all of the wire after use, the “rope” (60LB braided fishing line) only iced up once. (Also limited corrosion) (I though of putting an “Ice/water Stripper Cartridge” in the vacant pockets where the roper enters. No testing though. I think that weather is the main reason someone else (SteppIR?) has not ever sold such an antenna.

I would love to implement closed loop operation. After running my 3d printer for 20 hour print jobs without issues, I decided that as long as the stepper was powerful enough to never skip, there was not problem with home position being lost. (I tried a “homing routine” that would pull the wire in at reduced power, and sense the stall. My 3D printer bumps the frame to find out where it is before it starts. )

More comments buried in your text….

On Jan 5, 2022, at 8:16 PM, WA1RCT @.***> wrote:

HI Eric, Thank you so much for the quick reply. Here are my thoughts. I currently have a folded dipole which works 'ok' from 160M to 10M. I've been playing with auto tuners (built up a ATU-100 model recently), but I agree with you that having a resonant antenna is the best starting point. My personal goal would be to try to develop an antenna for my setup that will work well across that entire range. I have an IC-7300 rig, and run digital often, so I would want the antenna to handle 100w-200w without any issues. I have fellow hams who might be interested, and they run 1kw+. My current dipole is 140 feet, suspended from trees, with an additional support rope at the center point (all support ropes are on pulleys for easy raising and lowering). So I believe I could put some weight at the center (even without a tower). I was thinking of a setup similar to your prototype, and then googled it and found you. I've reached out to a friend that I previously worked with. He is a highly skilled mechanical engineer who has spent his career designing the mechanical parts of medical products, including some that used small precision motors and cables. If he would be willing to provide any component selection advice or provide any guidance, I think this would help me alot. For me the mechanical aspects would be the biggest challenge. For the electrical and software, I have tons of ideas for automating the system. I'm thinking of getting a raspberry pi to run it (and I think it can also run your software). I am confident I could automate this to work any way I'd like.(I prefer fully automatic systems, and usually the best solution is closed loop)

Node-Red made the software development quick and easy, but is a really FAT solution to a simple problem. (I run the Node-Red server on a pi that serves up the webpage. The pi does all the work.) (Depending on the motor controller, this could all be eliminated.)

From what I've seen on your website, here are my thoughts: 1) the cable/wire will need to be enclosed to work in New England (ice and snow). My thought is to have a rope running the entire length of the antenna, and hanging a flexible tube under it, and the wire+rope/cable will run completely inside the tube. At each end there would be a pulley on a spring (inside the tube, I've found some very small pulleys, check out Harken) The only problem I found with small pulleys was the induced friction caused by “ going around the corner” I ended up with 2 inch pulleys to get things the “glide”. (Even though I have been a sailor, I never thought of Harken for supplies, a good idea!) and the far ends of the tube would be sealed. THen where it meets the center unit, the tubes would have to be attached weathertight to the unit. 2) I think you bring up very good points about the motor and the spools. I don't know the best radius to consider, but I'd have to worry about life of the wire and the rope/cable bending so often. Have you looked into that? Yes, 3 inches was small enough for the motor to turn, and the small size made the entire package a LOT smaller (see pictures of my wood prototype with 6 inch spools) After LOTS of cycles, the wire seemed OK with anything over 1.5 inches.

Also have you looked into corrosion on the cable, or just having the copper

build up surface resistance as it weathers?

I do use “tinned” cable and retract after use. Had no real corrosion after a summer outside.

This would create resistance and then when coiled it wouldn't have the low resistance we need. Have you considered tinned wire? Does that change the flexibility of the cable? Not much!

3) I was thinking of using small diameter dacron or dyneema rope, and then I found some flexible wire (almost like grounding braid). For high power, we would need to consider heavier gauge, maybe even 12 gauge. That will get heavy, and be much tougher to run on the spool. 4) I like your spools. I was thinking of using a bolt at the center as the axle, and attaching the wire to the bolt (I had assumed 2 separate wheels, each on a separate axle), and then the brush simply touches a bolt head that rotates, rather than touches a moving wire. But this would require 2 separate axles (or at least an insulator between the spool axle. That would work! As long as you “wind in” as much as you “wind out” - hence the couple spools. SteppIR uses two spools, but still “rubs” a brush on the wire itself.

Mr friend suggested using insulated wire and a central brush, but I explained that the resulting coil would be really bad. See GitHUB illustration.

Another option that would help with weather is to modify the RTV80 by W4QJP so that the wire is out all the time, and the ropes just move the “fold point” back and forth! (No brushes!, except for the moving shorting contract at the moving ends. maybe less critical?)

5) I don't know much about the strength of stepper motors, or how much force you need to turn the spools.

The NEMA 17 (when driven in micro step mode) had more than enough power for a 3 inch spools and system friction. It was barely adequate with 6 inch spools, but a reduction drive or bigger motor would fix this. SteppIR uses a pretty big motor for its “tapes”.

You can buy some pretty big stepper motors for less than $100. You can also buy some closed loop motors for $350. (yikes) Maybe a DC motor with a position encoder could move anything...

6) I do have another friend who has a 3D printer, so I could ask him to print up some parts for me.

The whole thing could be made with hardware store parts (Pipe, external fittings, etc.)
More ugly but probably more robust for a tower installation.

Maybe a cross between my plastic parts and the Collins hand-powered winch. https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt

Good luck. I’d love to see such an antenna really high up! Too bad a big high dipole (Even fixed) is a lot of trouble. If I were still on the farm with my 10 acre farmstead, I would take what I’ve learned and put an 8 inch across, 18 inch high plastic Nema box upstairs, and just print a few internal parts for spools and brushes.) I think that using a 200lb test monofilament might not have much ice sticking to it?

Of course a perfectly resonant dipole is 70 ohms, so perfection is still ways off :-)

In AM radio, we used a “matching network” (NOT a TUNER according to the chief engineer) to get from the antenna’s impedance to something around 600 ohms (if I remember from the 70’s)

Eric.

Your thoughts? Dave WA1RCT

On Wed, Jan 5, 2022 at 8:15 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note!

I would be happy to help in any way I can to improve the antenna system. I enjoy the engineering stuff a lot!

I have been interested in antenna physics since high school. Having been trained as a broadcast engineer, I was always somewhat surprised by the ”If your tuner can fix the SWR - it’s good enough” attitude that a lot of HAM’s seem to operate with. (In AM radio, we designed the antenna to be near-perfect, and then designed everything else for the best efficiency.)

The project on GitHUB was at first a platform to experiment with the physics, and mutated into a useful antenna for a friend.

I have found the prototype durable enough for temporary use like field days and similar operation. (3 guyed 41 foot poles) The housing is PETG rather than PLA, I had intended to paint it if needed.

The small size is a compromise. If I were to build another for long term use on a good tower, I’d switch to a better (bigger?) motor.

Larger diameter spools would hold thicker wire, but would require more torque than NEMA 17 (which I already had) would provide.

Wide spools would hold thicker wire, but would “wind” inconsistently resulting in tangles.

I tried a lot of iterations of various parts, and came up with the compromise that works well in my environment.

I considered using outdoor rated PVC pipe or similar for the housing with add-on external brush-holder thingies instead of printing the whole thing. I tried copper alloy “brushes” with good success (Copying SteppIR), but found the replaceable carbon brushes to last well. From an electrical engineering point of view, the important part is to have non-conducting spools - I don’t think a metal case would be out fo the question. Also tried belt drive reduction for more torque, but found it too complicated and hard to keep adjusted (Belts were hard to find the right size). I considered an ESP32 based system, as well as ditching the WIFI altogether and just making a USB connected controller - The WIFI Stepper product just made “the first try” easier since I had no experience with stepper motors.

I am currently working on building a static web page with a tiny bit of Javascript in place of NODE-RED and the required server. (If you stick with the WIFI stepper product, an HTTP “get” statement is all that you need to send in order to send commands.)

I’d be interested in what you think.

Eric.

AD0MZ

@.***

On Jan 5, 2022, at 4:05 PM, WA1RCT @.***> wrote:

Hi Eric, This looks really cool. I was thinking of doing something like this myself, and would like to try to make a version that I could use as my primary antenna. I think there are a number of areas that would need to be modified so that it would survive outdoors and be reliable. I'd like to work on that. I'm a electrical/software engineer by profession, but do not have training in mechanical design. Could you reply with your email address, and I can reach out to you, and see if there are things I could work on.

Thanks, Dave Hempstead WA1RCT

— Reply to this email directly, view it on GitHub < https://github.com/AD0MZ/All-Band-Adjustable-Dipole/issues/2>, or unsubscribe < https://github.com/notifications/unsubscribe-auth/AS25NSC3K6LTJS5VICSUYFDUUS6A5ANCNFSM5LK6EP7Q . Triage notifications on the go with GitHub Mobile for iOS < https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android < https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

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You are receiving this because you authored the thread.Message ID: @.***>

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Thanks Eric, Could you send me your email address, and we can continue this separately? Dave

On Wed, Jan 5, 2022 at 10:08 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note.

Like you, here in Minnesota - I worried about ice a bit. I found that if I retracted all of the wire after use, the “rope” (60LB braided fishing line) only iced up once. (Also limited corrosion) (I though of putting an “Ice/water Stripper Cartridge” in the vacant pockets where the roper enters. No testing though. I think that weather is the main reason someone else (SteppIR?) has not ever sold such an antenna.

I would love to implement closed loop operation. After running my 3d printer for 20 hour print jobs without issues, I decided that as long as the stepper was powerful enough to never skip, there was not problem with home position being lost. (I tried a “homing routine” that would pull the wire in at reduced power, and sense the stall. My 3D printer bumps the frame to find out where it is before it starts. )

More comments buried in your text….

On Jan 5, 2022, at 8:16 PM, WA1RCT @.***> wrote:

HI Eric, Thank you so much for the quick reply. Here are my thoughts. I currently have a folded dipole which works 'ok' from 160M to 10M. I've been playing with auto tuners (built up a ATU-100 model recently), but I agree with you that having a resonant antenna is the best starting point. My personal goal would be to try to develop an antenna for my setup that will work well across that entire range. I have an IC-7300 rig, and run digital often, so I would want the antenna to handle 100w-200w without any issues. I have fellow hams who might be interested, and they run 1kw+. My current dipole is 140 feet, suspended from trees, with an additional support rope at the center point (all support ropes are on pulleys for easy raising and lowering). So I believe I could put some weight at the center (even without a tower). I was thinking of a setup similar to your prototype, and then googled it and found you. I've reached out to a friend that I previously worked with. He is a highly skilled mechanical engineer who has spent his career designing the mechanical parts of medical products, including some that used small precision motors and cables. If he would be willing to provide any component selection advice or provide any guidance, I think this would help me alot. For me the mechanical aspects would be the biggest challenge. For the electrical and software, I have tons of ideas for automating the system. I'm thinking of getting a raspberry pi to run it (and I think it can also run your software). I am confident I could automate this to work any way I'd like.(I prefer fully automatic systems, and usually the best solution is closed loop)

Node-Red made the software development quick and easy, but is a really FAT solution to a simple problem. (I run the Node-Red server on a pi that serves up the webpage. The pi does all the work.) (Depending on the motor controller, this could all be eliminated.)

From what I've seen on your website, here are my thoughts: 1) the cable/wire will need to be enclosed to work in New England (ice and snow). My thought is to have a rope running the entire length of the antenna, and hanging a flexible tube under it, and the wire+rope/cable will run completely inside the tube. At each end there would be a pulley on a spring (inside the tube, I've found some very small pulleys, check out Harken) The only problem I found with small pulleys was the induced friction caused by “ going around the corner” I ended up with 2 inch pulleys to get things the “glide”. (Even though I have been a sailor, I never thought of Harken for supplies, a good idea!) and the far ends of the tube would be sealed. THen where it meets the center unit, the tubes would have to be attached weathertight to the unit. 2) I think you bring up very good points about the motor and the spools. I don't know the best radius to consider, but I'd have to worry about life of the wire and the rope/cable bending so often. Have you looked into that? Yes, 3 inches was small enough for the motor to turn, and the small size made the entire package a LOT smaller (see pictures of my wood prototype with 6 inch spools) After LOTS of cycles, the wire seemed OK with anything over 1.5 inches.

Also have you looked into corrosion on the cable, or just having the copper

build up surface resistance as it weathers?

I do use “tinned” cable and retract after use. Had no real corrosion after a summer outside.

This would create resistance and then when coiled it wouldn't have the low resistance we need. Have you considered tinned wire? Does that change the flexibility of the cable? Not much!

3) I was thinking of using small diameter dacron or dyneema rope, and then I found some flexible wire (almost like grounding braid). For high power, we would need to consider heavier gauge, maybe even 12 gauge. That will get heavy, and be much tougher to run on the spool. 4) I like your spools. I was thinking of using a bolt at the center as the axle, and attaching the wire to the bolt (I had assumed 2 separate wheels, each on a separate axle), and then the brush simply touches a bolt head that rotates, rather than touches a moving wire. But this would require 2 separate axles (or at least an insulator between the spool axle. That would work! As long as you “wind in” as much as you “wind out” - hence the couple spools. SteppIR uses two spools, but still “rubs” a brush on the wire itself.

Mr friend suggested using insulated wire and a central brush, but I explained that the resulting coil would be really bad. See GitHUB illustration.

Another option that would help with weather is to modify the RTV80 by W4QJP so that the wire is out all the time, and the ropes just move the “fold point” back and forth! (No brushes!, except for the moving shorting contract at the moving ends. maybe less critical?)

5) I don't know much about the strength of stepper motors, or how much force you need to turn the spools.

The NEMA 17 (when driven in micro step mode) had more than enough power for a 3 inch spools and system friction. It was barely adequate with 6 inch spools, but a reduction drive or bigger motor would fix this. SteppIR uses a pretty big motor for its “tapes”.

You can buy some pretty big stepper motors for less than $100. You can also buy some closed loop motors for $350. (yikes) Maybe a DC motor with a position encoder could move anything...

6) I do have another friend who has a 3D printer, so I could ask him to print up some parts for me.

The whole thing could be made with hardware store parts (Pipe, external fittings, etc.) More ugly but probably more robust for a tower installation.

Maybe a cross between my plastic parts and the Collins hand-powered winch.

https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt < https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt

Good luck. I’d love to see such an antenna really high up! Too bad a big high dipole (Even fixed) is a lot of trouble. If I were still on the farm with my 10 acre farmstead, I would take what I’ve learned and put an 8 inch across, 18 inch high plastic Nema box upstairs, and just print a few internal parts for spools and brushes.) I think that using a 200lb test monofilament might not have much ice sticking to it?

Of course a perfectly resonant dipole is 70 ohms, so perfection is still ways off :-)

In AM radio, we used a “matching network” (NOT a TUNER according to the chief engineer) to get from the antenna’s impedance to something around 600 ohms (if I remember from the 70’s)

Eric.

Your thoughts? Dave WA1RCT

On Wed, Jan 5, 2022 at 8:15 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note!

I would be happy to help in any way I can to improve the antenna system. I enjoy the engineering stuff a lot!

I have been interested in antenna physics since high school. Having been trained as a broadcast engineer, I was always somewhat surprised by the ”If your tuner can fix the SWR - it’s good enough” attitude that a lot of HAM’s seem to operate with. (In AM radio, we designed the antenna to be near-perfect, and then designed everything else for the best efficiency.)

The project on GitHUB was at first a platform to experiment with the physics, and mutated into a useful antenna for a friend.

I have found the prototype durable enough for temporary use like field days and similar operation. (3 guyed 41 foot poles) The housing is PETG rather than PLA, I had intended to paint it if needed.

The small size is a compromise. If I were to build another for long term use on a good tower, I’d switch to a better (bigger?) motor.

Larger diameter spools would hold thicker wire, but would require more torque than NEMA 17 (which I already had) would provide.

Wide spools would hold thicker wire, but would “wind” inconsistently resulting in tangles.

I tried a lot of iterations of various parts, and came up with the compromise that works well in my environment.

I considered using outdoor rated PVC pipe or similar for the housing with add-on external brush-holder thingies instead of printing the whole thing. I tried copper alloy “brushes” with good success (Copying SteppIR), but found the replaceable carbon brushes to last well. From an electrical engineering point of view, the important part is to have non-conducting spools - I don’t think a metal case would be out fo the question. Also tried belt drive reduction for more torque, but found it too complicated and hard to keep adjusted (Belts were hard to find the right size). I considered an ESP32 based system, as well as ditching the WIFI altogether and just making a USB connected controller - The WIFI Stepper product just made “the first try” easier since I had no experience with stepper motors.

I am currently working on building a static web page with a tiny bit of Javascript in place of NODE-RED and the required server. (If you stick with the WIFI stepper product, an HTTP “get” statement is all that you need to send in order to send commands.)

I’d be interested in what you think.

Eric.

AD0MZ

@.***

On Jan 5, 2022, at 4:05 PM, WA1RCT @.***> wrote:

Hi Eric, This looks really cool. I was thinking of doing something like this myself, and would like to try to make a version that I could use as my primary antenna. I think there are a number of areas that would need to be modified so that it would survive outdoors and be reliable. I'd like to work on that. I'm a electrical/software engineer by profession, but do not have training in mechanical design. Could you reply with your email address, and I can reach out to you, and see if there are things I could work on.

Thanks, Dave Hempstead WA1RCT

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Sure . I am @. Jan 5, 2022 9:14 PM, WA1RCT @.> wrote:

Thanks Eric, Could you send me your email address, and we can continue

this separately?

Dave

On Wed, Jan 5, 2022 at 10:08 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note.

Like you, here in Minnesota - I worried about ice a bit.

I found that if I retracted all of the wire after use, the “rope” (60LB

braided fishing line) only iced up once.

(Also limited corrosion) (I though of putting an “Ice/water Stripper

Cartridge” in the vacant pockets where the roper enters. No testing though.

I think that weather is the main reason someone else (SteppIR?) has not

ever sold such an antenna.

I would love to implement closed loop operation. After running my 3d

printer for 20 hour print jobs without issues,

I decided that as long as the stepper was powerful enough to never skip,

there was not problem with home position being lost.

(I tried a “homing routine” that would pull the wire in at reduced power,

and sense the stall.

My 3D printer bumps the frame to find out where it is before it starts. )

More comments buried in your text….

On Jan 5, 2022, at 8:16 PM, WA1RCT @.***> wrote:

HI Eric,

Thank you so much for the quick reply. Here are my thoughts.

I currently have a folded dipole which works 'ok' from 160M to 10M.

I've been playing with auto tuners (built up a ATU-100 model recently),

but

I agree with you that having a resonant antenna is the best starting

point.

My personal goal would be to try to develop an antenna for my setup that

will work well across that entire range. I have an IC-7300 rig, and run

digital often, so I would want the antenna to handle 100w-200w without

any

issues. I have fellow hams who might be interested, and they run 1kw+.

My current dipole is 140 feet, suspended from trees, with an additional

support rope at the center point (all support ropes are on pulleys for

easy

raising and lowering). So I believe I could put some weight at the center

(even without a tower).

I was thinking of a setup similar to your prototype, and then googled it

and found you.

I've reached out to a friend that I previously worked with. He is a

highly skilled mechanical engineer who has spent his career designing the

mechanical parts of medical products, including some that used small

precision motors and cables. If he would be willing to provide any

component selection advice or provide any guidance, I think this would

help

me alot.

For me the mechanical aspects would be the biggest challenge. For the

electrical and software, I have tons of ideas for automating the system.

I'm thinking of getting a raspberry pi to run it (and I think it can also

run your software). I am confident I could automate this to work any way

I'd like.(I prefer fully automatic systems, and usually the best solution

is closed loop)

Node-Red made the software development quick and easy, but is a really FAT

solution to a simple problem.

(I run the Node-Red server on a pi that serves up the webpage. The pi does

all the work.)

(Depending on the motor controller, this could all be eliminated.)

From what I've seen on your website, here are my thoughts:

1) the cable/wire will need to be enclosed to work in New England (ice

and

snow). My thought is to have a rope running the entire length of the

antenna, and hanging a flexible tube under it, and the wire+rope/cable

will

run completely inside the tube. At each end there would be a pulley on a

spring (inside the tube, I've found some very small pulleys, check out

Harken) The only problem I found with small pulleys was the induced

friction caused by “

going around the corner” I ended up with 2 inch pulleys to get things the

“glide”.

(Even though I have been a sailor, I never thought of Harken for supplies,

a good idea!)

and the far ends of the tube would be sealed. THen where it meets

the center unit, the tubes would have to be attached weathertight to the

unit.

2) I think you bring up very good points about the motor and the spools.

I

don't know the best radius to consider, but I'd have to worry about life

of

the wire and the rope/cable bending so often. Have you looked into that?

Yes, 3 inches was small enough for the motor to turn, and the small size

made the entire package a LOT smaller (see pictures of my wood prototype

with 6 inch spools)

After LOTS of cycles, the wire seemed OK with anything over 1.5 inches.

Also have you looked into corrosion on the cable, or just having the

copper

build up surface resistance as it weathers?

I do use “tinned” cable and retract after use. Had no real corrosion

after a summer outside.

This would create resistance

and then when coiled it wouldn't have the low resistance we need. Have

you

considered tinned wire? Does that change the flexibility of the cable?

Not much!

3) I was thinking of using small diameter dacron or dyneema rope, and

then

I found some flexible wire (almost like grounding braid). For high power,

we would need to consider heavier gauge, maybe even 12 gauge. That will

get heavy, and be much tougher to run on the spool.

4) I like your spools. I was thinking of using a bolt at the center as

the

axle, and attaching the wire to the bolt (I had assumed 2 separate

wheels,

each on a separate axle), and then the brush simply touches a bolt head

that rotates, rather than touches a moving wire. But this would require 2

separate axles (or at least an insulator between the spool axle.

That would work! As long as you “wind in” as much as you “wind out” -

hence the couple spools.

SteppIR uses two spools, but still “rubs” a brush on the wire itself.

Mr friend suggested using insulated wire and a central brush, but I

explained that the resulting coil would be really bad. See GitHUB

illustration.

Another option that would help with weather is to modify the RTV80 by

W4QJP so that the wire is out all the time, and the ropes just move the

“fold point” back and forth!

(No brushes!, except for the moving shorting contract at the moving ends.

maybe less critical?)

5) I don't know much about the strength of stepper motors, or how much

force you need to turn the spools.

The NEMA 17 (when driven in micro step mode) had more than enough power

for a 3 inch spools and system friction.

It was barely adequate with 6 inch spools, but a reduction drive or bigger

motor would fix this.

SteppIR uses a pretty big motor for its “tapes”.

You can buy some pretty big stepper motors for less than $100. You can

also buy some closed loop motors for $350. (yikes)

Maybe a DC motor with a position encoder could move anything...

6) I do have another friend who has a 3D printer, so I could ask him to

print up some parts for me.

The whole thing could be made with hardware store parts (Pipe, external

fittings, etc.)

More ugly but probably more robust for a tower installation.

Maybe a cross between my plastic parts and the Collins hand-powered winch.

https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt

<

https://www.ebay.com/itm/184927161352?hash=item2b0e848c08:g:AzkAAOSwc~Nfqxbt

Good luck.

I’d love to see such an antenna really high up! Too bad a big high dipole

(Even fixed) is a lot of trouble.

If I were still on the farm with my 10 acre farmstead, I would take what

I’ve learned and put an 8 inch across, 18 inch high plastic Nema box

upstairs,

and just print a few internal parts for spools and brushes.) I think that

using a 200lb test monofilament might not have much ice sticking to it?

Of course a perfectly resonant dipole is 70 ohms, so perfection is still

ways off :-)

In AM radio, we used a “matching network” (NOT a TUNER according to the

chief engineer)

to get from the antenna’s impedance to something around 600 ohms (if I

remember from the 70’s)

Eric.

Your thoughts?

Dave

WA1RCT

On Wed, Jan 5, 2022 at 8:15 PM AD0MZ @.***> wrote:

Dear Dave:

Thanks for the note!

I would be happy to help in any way I can to improve the antenna

system. I

enjoy the engineering stuff a lot!

I have been interested in antenna physics since high school.

Having been trained as a broadcast engineer, I was always somewhat

surprised by the ”If your tuner can fix the SWR - it’s good enough”

attitude that a lot of HAM’s seem to operate with.

(In AM radio, we designed the antenna to be near-perfect, and then

designed everything else for the best efficiency.)

The project on GitHUB was at first a platform to experiment with the

physics, and mutated into a useful antenna for a friend.

I have found the prototype durable enough for temporary use like field

days and similar operation. (3 guyed 41 foot poles)

The housing is PETG rather than PLA, I had intended to paint it if

needed.

The small size is a compromise. If I were to build another for long

term

use on a good tower, I’d switch to a better (bigger?) motor.

Larger diameter spools would hold thicker wire, but would require

more

torque than NEMA 17 (which I already had) would provide.

Wide spools would hold thicker wire, but would “wind” inconsistently

resulting in tangles.

I tried a lot of iterations of various parts, and came up with the

compromise that works well in my environment.

I considered using outdoor rated PVC pipe or similar for the housing

with

add-on external brush-holder thingies instead of printing the whole

thing.

I tried copper alloy “brushes” with good success (Copying SteppIR), but

found the replaceable carbon brushes to last well.

From an electrical engineering point of view, the important part is to

have non-conducting spools - I don’t think a metal case would be out

fo the

question.

Also tried belt drive reduction for more torque, but found it too

complicated and hard to keep adjusted (Belts were hard to find the

right

size).

I considered an ESP32 based system, as well as ditching the WIFI

altogether and just making a USB connected controller -

The WIFI Stepper product just made “the first try” easier since I had

no

experience with stepper motors.

I am currently working on building a static web page with a tiny bit of

Javascript in place of NODE-RED and the required server.

(If you stick with the WIFI stepper product, an HTTP “get” statement is

all that you need to send in order to send commands.)

I’d be interested in what you think.

Eric.

AD0MZ

@.***

On Jan 5, 2022, at 4:05 PM, WA1RCT @.***> wrote:

Hi Eric,

This looks really cool. I was thinking of doing something like this

myself, and would like to try to make a version that I could use as my

primary antenna. I think there are a number of areas that would need

to be

modified so that it would survive outdoors and be reliable. I'd like to

work on that. I'm a electrical/software engineer by profession, but do

not

have training in mechanical design. Could you reply with your email

address, and I can reach out to you, and see if there are things I

could

work on.

Thanks,

Dave Hempstead

WA1RCT

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Hi Eric, Ha, github blanks out email addresses. We'll have to find another way to get them to each other. Dave

AD0MZ / All-Band-Adjustable-Dipole

Can we work to improve this? #2