CB and Ham Radio Techs Love Their Bird Wattmeters

[joeqsmith]

Well, you can't really refer to those folks as CB'ers....

I guess you're suggesting hams that can't use Morse code aren't really hams?   I think I follow.   

, and I'm sure they're not tuning with a Dosy. I bet the middle of the bell are your 20W overmodulated radios to a high swing 2W driving a 400W linear truckers running some base load short antenna. It's not gonna matter if your modulation or reflected power is reading 20% off. The bigger concern is, how long should your coax to the antenna be to get a proper reading. 

I really don't know what would be important.  Both groups buy some equipment, plug it in, blab.  If their concern is return loss,  I they could buy three spools of this:

https://www.tessco.com/product/rg58-u-coaxial-cable-500ft-29781 

Place them in series with your 30s UHF connectors.  Should give you a rood return loss. 

[metrologist]

I guess you're suggesting hams that can't use Morse code aren't really hams?   I think I follow.   

  tens of kW keydowns are not part of the specification, and neither were the antics of K1MAN. Code is part of the ham culture and a former requirement, but I got into it for technical reasons, to design, build, and test antennas.

I really don't know what would be important.  Both groups buy some equipment, plug it in, blab.  If their concern is return loss,  I they could buy three spools of this:

https://www.tessco.com/product/rg58-u-coaxial-cable-500ft-29781 

Place them in series with your 30s UHF connectors.  Should give you a rood return loss.

Yeah, that should work. Reminds me of the time my 100 foot run of RG-8U coax pulled out of the connector at the antenna and landed in the back yard for the winter. Silly boy did not apply any sort of strain relief. The coax soaked up the winter elements and at the station, perfect match but dead ears.

[metrologist]

Not too much more to do on the shielding. The top, bottom, and faceplates will all touch copper-to-copper when assembled. I will run one copper braid bonding wire from the electronics ground to the copper shield by soldering it to a piece of copper tape.

I did find some aluminum cases on Amazon that would work for the size I need. I think I ran across some before but I decided to get the plastic case because I was turned off by the price. But, they are available -

Amazon aluminum case

That looks beautiful, but too much work for me...isn't there a spray for that?

[xrunner]

Not too much more to do on the shielding. The top, bottom, and faceplates will all touch copper-to-copper when assembled. I will run one copper braid bonding wire from the electronics ground to the copper shield by soldering it to a piece of copper tape.

I did find some aluminum cases on Amazon that would work for the size I need. I think I ran across some before but I decided to get the plastic case because I was turned off by the price. But, they are available -

Amazon aluminum case

That looks beautiful, but too much work for me...isn't there a spray for that?

I never found a spray that was a simple, affordable solution like a Krylon sort of thing. I never found a paint that was a small amount that was affordable or that reviews said really worked. No - "metal" spray paint is not conductive in case anyone out there doesn't know. 5 gallon cans or tiny bottles of conductive paint - oh sure but too much or too little and expensive.

Question: The copper tape has conductive adhesive. So even though I used many pieces to do this job, it is conductive from any two points with about 3 or 4 ohms resistance. But here's a question - what makes the adhesive conductive at all? Hmmm ... why can't I get whatever the secret ingredient is that makes it conductive in a small size? Oh because it's secret? No really, if anyone knows how the adhesive is made conductive please let me know.

The best solution is to just pay more for a larger aluminum case like the smaller ones I've used for two other power meter projects. I was just being an extreme tightwad which comes from hanging around, ummm, a certain group of people since I was a teenager. So I opted for a cheaper plastic case. The metal front and back panels that they come with are set aside, and then substituted with custom designed and 3D printed designs that accommodate the OLED display and other controls and interfaces on the front and back. But the shielding on those 3D printed flat panels is very easy to do with copper tape. The mounting plate for the electronics is also custom printed and simply slides in on the case rail slots which are built-into the case. This plastic case, due to the "ribs" on the sides and raised nubs for custom mounting, made it difficult to apply the tape in this situation. Otherwise it wouldn't have been that hard to do.

[joeqsmith]

I guess you're suggesting hams that can't use Morse code aren't really hams?   I think I follow.   

  tens of kW keydowns are not part of the specification, and neither were the antics of K1MAN. Code is part of the ham culture and a former requirement, but I got into it for technical reasons, to design, build, and test antennas.

By specification I assume you mean regulations.  I have no idea what they are so a quick search:

https://www.fcc.gov/wireless/bureau-divisions/mobility-division/citizens-band-radio-service-cbrs

You may not raise the power output of a CB transmitter.
You may not attach a "linear," "linear amplifier" or any other type of power amplifier to your CB transmitter.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-D

(a) When transmitting amplitude modulated (AM) voice signals or frequency modulated (FM) voice signals, the mean carrier power must not exceed 4 Watts.
(b) When transmitting single sideband (SSB) voice signals, the peak envelope power must not exceed 12 Watts.

Lets assume what you previously wrote is correct:

I bet the middle of the bell are your 20W overmodulated radios to a high swing 2W driving a 400W linear truckers running some base load short antenna. It's not gonna matter if your modulation or reflected power is reading 20% off. The bigger concern is, how long should your coax to the antenna be to get a proper reading. 

So even though is seems the culture operates outside the regulations,  the majority are not considered a CBers?   If I follow your logic, CBers are actually very rare, like hams with any level of technical skills.   Their out there but good luck finding them...   

[joeqsmith]

Question: The copper tape has conductive adhesive. So even though I used many pieces to do this job, it is conductive from any two points with about 3 or 4 ohms resistance. But here's a question - what makes the adhesive conductive at all? Hmmm ... why can't I get whatever the secret ingredient is that makes it conductive in a small size? Oh because it's secret? No really, if anyone knows how the adhesive is made conductive please let me know.

That is very interesting as I have used 3M copper foil tape for years.  I have two different spools sitting here now.  Both have a non-conductive adhesive.  For RF I normally don't care.  If I use it for DC, I solder the seams.     

Post the brand/part number for what you are using.   

[xrunner]

That is very interesting as I have used 3M copper foil tape for years.  I have two different spools sitting here now.  Both have a non-conductive adhesive.  For RF I normally don't care.  If I use it for DC, I solder the seams.     

Post the brand/part number for what you are using.

I found it on Amazon several years ago. It wasn't hard to find and they have different widths to choose from. When I got the first roll I was skeptical it really had conductive adhesive so I tested it. Sure enough it actually was. You can stick one piece to another as much as you need and it is a pretty low ohmage. Check the pic of my finished case. I'm getting about 8 ohms from front to back and that's just copper touching copper or passing through pieces stuck together.

Here's just one supplier I bought from on Amazon -

copper tape conductive adhesive

https://www.amazon.com/dp/B0C1442K27?ref=ppx_yo2ov_dt_b_product_details&th=1

[metrologist]

By specification I assume you mean regulations.  I have no idea what they are so a quick search:

Well, pedantics  The equipment is type certified.

Lets assume what you previously wrote is correct:
So even though is seems the culture operates outside the regulations,  the majority are not considered a CBers?   If I follow your logic, CBers are actually very rare, like hams with any level of technical skills.   Their out there but good luck finding them...   

Well, like many things in life, folks often operate on the outside fringes of where they ought to. The point is, most folks operating in the citizens band don't need more than something like a Dosy meter.

And which hams you find depends on your circle of friends. Our ham club is filled with engineers, many with advanced degrees and even PhD's in the electronics field who hold many patents.

I was looking for my first SWR meter, I believe a Micronta. I do still have this one, made in Japan. I bet it's pretty good.

https://www.ebay.com/itm/404518688018

[joeqsmith]

By specification I assume you mean regulations.  I have no idea what they are so a quick search:

Well, pedantics  The equipment is type certified.

I'm not sure what "type certified" would mean.  The non-CBer buys their linear from hot rod joe, I doubt it has any certification outside of how many Bird Watts it produces.   If you send your production radio to hot rod joe to tune get that 20W overmodulated  signal you mention, I would imagine any factory cert is void.  In both cases the non-CBer has violated the regulations.   I'm sure there is a point you are making about the non-CBer but I am missing it.

When I was looking for the regulations, I stumbled onto an area of the FCC's site where they talk about hams also violating regulations with some decent fines.    I guess these people, even though licensed are also not really hams?   

********

And which hams you find depends on your circle of friends. Our ham club is filled with engineers, many with advanced degrees and even PhD's in the electronics field who hold many patents.

I don't think I have any friends who are licensed hams.  Any of my interactions come from the ones who post in the forums or send private messages. 

[joeqsmith]

I found it on Amazon several years ago. .....
copper tape conductive adhesive

https://www.amazon.com/dp/B0C1442K27?ref=ppx_yo2ov_dt_b_product_details&th=1

Thanks for the link.   I'll order some.     

[xrunner]

Thanks for the link.   I'll order some.     

Good, like to hear your opinion of it. Here's a little experiment for you. I haven't ever tried to send a current through this type of copper tape with the conductive adhesive actually taking an intentional current of some magnitude. Let's do it.

I have a 100 ohm 10W resistor and six pieces of copper tape with conductive adhesive in series. I soldered onto two of the pieces each a wire. I then made a conductive path which depends on the adhesive to allow current to flow. Specifically, there are five places that touch only with the adhesive so the current must flow through it.

I applied 20 V which gave me 200 mA. I let it sit for 10 minutes. The resistor got too hot to touch but the tape is not warm at all. It dropped about 0.3 V across the tape which gives 1.5 ohms of resistance for the tape path.

I backed it off to 10 V (100 mA) and will allow it to operate for several hours this evening to see if the adhesive breaks down. I will report on that later ...

[joeqsmith]

That may prove useful in the future.  I didn't understand the point of adding the resistor.   

[xrunner]

I just turned the experiment off, it was working fine no issues with the tape. The resistance of the copper tape "element" actually went down to about 1 ohm.

I used an additional resistor because the resistance of the adhesive elements of tape are hard to set to an exact current with it as the only resistive element. The adhesive is not a hard and fast resistive element but it's resistance appears to change with applied voltage a bit. Anyway, the point is it conducts pretty well. I'd like to see what tests you may want to do with it yourself.

[joeqsmith]

I just turned the experiment off, it was working fine no issues with the tape. The resistance of the copper tape "element" actually went down to about 1 ohm.

I used an additional resistor because the resistance of the adhesive elements of tape are hard to set to an exact current with it as the only resistive element. The adhesive is not a hard and fast resistive element but it's resistance appears to change with applied voltage a bit. Anyway, the point is it conducts pretty well. I'd like to see what tests you may want to do with it yourself.

I would have guessed your PS would run CC mode into a dead short and be stable. 

Sounds like it works well for DC.   The idea you could stick it to a conductive surface without solder and get a decent connection may prove to be very useful depending how well it adheres and how difficult it is to clean the residue once removed.   

***
Normally I use foil tape for RF but with the conductive adhesive, maybe it could be a much simpler approach to probing and other...
https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg5164857/#msg5164857

[xrunner]

Shielding all finished. If nothing else it looks good inside the case.

Next I had to prepare the two holes in the top half of the case for M3 bolts. These two holes accept the bolts which hold the case halves together. The holes were meant for the self-tapping screws that came with the case which were too short after my increased height mod. So I drilled them to the proper size for the M3 tap and finished that task.

Next I need to get the rf patch cables made up which connect the rf in and rf out to the Putnam coupler.

[xrunner]

Yes I'm making progress. Working on the rf in - out connections. It's a tight fit. Might finish this project before the end of the year.

Notice I didn't say what year. 

[vk4ffab]

Might finish this project before the end of the year.

Notice I didn't say what year. 

That is all my projects LOL

[joeqsmith]

I just turned the experiment off, it was working fine no issues with the tape. The resistance of the copper tape "element" actually went down to about 1 ohm.

I used an additional resistor because the resistance of the adhesive elements of tape are hard to set to an exact current with it as the only resistive element. The adhesive is not a hard and fast resistive element but it's resistance appears to change with applied voltage a bit. Anyway, the point is it conducts pretty well. I'd like to see what tests you may want to do with it yourself.

I would have guessed your PS would run CC mode into a dead short and be stable. 

Sounds like it works well for DC.   The idea you could stick it to a conductive surface without solder and get a decent connection may prove to be very useful depending how well it adheres and how difficult it is to clean the residue once removed.   

***
Normally I use foil tape for RF but with the conductive adhesive, maybe it could be a much simpler approach to probing and other...
https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg5164857/#msg5164857

I measured a thickness of 0.02mm (calipers).  About half the thickness of the 3M tape I normally use. 

I cut off a section 50mm X 15mm and had a look under the microscope.  I notice the bottom side has black spots all over it.  I wonder if that is some sort of conductive material that they dust onto the foil.   

I then attached both ends to two copper plates.  Each end used a surface of about 15mm^2.   Using my Kelvin leads, I measured 0.513 ohms.  I then pulled off the foil on one side and reattached it several times.

2 0.479
3 0.630
4 0.679
5 4.649
6 1.965
7 4.120

Looking at the area where I was attaching the tape, I did not see any residue.

Next I ran 1A through it (same used section) and noticed that it has become a bit intermittent.   Unlike your test, I just shorted the supply and set the limit.  No other resistors were used.  I had to use my finger nail to get a decent contact and let it set for 10 minutes.  No problems.   Had I started out with a fresh section, I'm sure it wouldn't have required me to fuss with it.

Next I tried some ProClean (methanol blend) on the adhesive.  The adhesive did not loosen up and once dried, stuck fine.

Last, I then tried soldering the stuck foil to the PCB material.  I would say its about as good as the 3M tape. 

Overall, I'm impressed how well it continued to stick and make decent contact.  That was a good find.  I'm sure I will find a few uses for this stuff.  The fact it doesn't appear to leave behind a lot of sticky residue, I can see using it for makeshift ground straps for probing.   

[xrunner]

I measured a thickness of 0.02mm (calipers).  About half the thickness of the 3M tape I normally use. 

I cut off a section 50mm X 15mm and had a look under the microscope.  I notice the bottom side has black spots all over it.  I wonder if that is some sort of conductive material that they dust onto the foil. 

I dunno I wish I knew what it was. Is it a non-conductive adhesive with the majic potion added later, or is the adhesive conductive specifically because it's made to be.

I then attached both ends to two copper plates.  Each end used a surface of about 15mm^2.   Using my Kelvin leads, I measured 0.513 ohms.  I then pulled off the foil on one side and reattached it several times.

2 0.479
3 0.630
4 0.679
5 4.649
6 1.965
7 4.120

Looking at the area where I was attaching the tape, I did not see any residue.

Next I ran 1A through it (same used section) and noticed that it has become a bit intermittent.   Unlike your test, I just shorted the supply and set the limit.  No other resistors were used.  I had to use my finger nail to get a decent contact and let it set for 10 minutes.  No problems.   Had I started out with a fresh section, I'm sure it wouldn't have required me to fuss with it.

Next I tried some ProClean (methanol blend) on the adhesive.  The adhesive did not loosen up and once dried, stuck fine.

Last, I then tried soldering the stuck foil to the PCB material.  I would say its about as good as the 3M tape. 

Overall, I'm impressed how well it continued to stick and make decent contact.  That was a good find.  I'm sure I will find a few uses for this stuff.  The fact it doesn't appear to leave behind a lot of sticky residue, I can see using it for makeshift ground straps for probing.

I'll examine my foil under a microscope. I want to find out how the adhesive is made, so I'm going to see if I can find more information on it.

*****

Small update. Had to fiddle with the length of the coax for a while to get it right. It's real tight in there for this size coax. Real tight. Got the two chassis connectors crimped on.

As Dave sez - Trap for young players:

After you get one end crimped make sure you put the heat shrink tubing on the coax (if you want it) for both ends before you crimp the other connector on. You get in a hurry or walk away for a while, you forget it.

That's why I got the cut heat shrink on the coax now and also taped the last ferrule on. If you push the pin in the connector and forget the ferrule you can pull apart the end but you'll have to pass the ferrule past the shielding strands which are pointing against it, which is a small hassle. But after you crimp the last end you ain't getting the heat shrink tubing on. Not having heat shrink isn't a big deal for this project it just makes the connection look professional.

I used to forget that all the time when I was younger. But not any more. No really I don't make mistakes any more.

[joeqsmith]

Probing from the copper side to the adhesive, if I touch off on the glue it is not conductive.  The black material is suspended in the adhesive.  If you move the glue around, the black material moves with it.  Maybe just a sprinkle of course carbon mixed in.  Can't add too much or the adhesive won't have enough surface area to stick. 

No really I don't make mistakes any more.

The only people I know who don't make mistakes don't do anything.  If you're not making mistakes, you're not learning. 

[xrunner]

The only people I know who don't make mistakes don't do anything.  If you're not making mistakes, you're not learning.

Does that apply to brain surgeons and airline pilots? 

[metrologist]

The only people I know who don't make mistakes don't do anything.  If you're not making mistakes, you're not learning.

Does that apply to brain surgeons and airline pilots? 

Did it apply to the Bud Light marketing person? 

[joeqsmith]

When I think of brain surgeons, I would normally think of Rose Kennedy.   Now that I am older, I have a few friend's doctors I also think of.

First hit from Google:  Oops, we worked on the wrong side... 
https://pa4law.com/neurosurgery-malpractice-when-surgeons-operate-on-the-wrong-area-of-the-brain/

There are different reasons why wrong-side craniotomies are performed. Reversed X-rays, procedural errors, and a surgeon failing to review a patient’s medical records are just a few factors that can come into play. Wrong-site surgeries are considered sentinel events, which are the worst kinds of medical errors. It’s hard to believe, but a  2007 study found that one out of four neurosurgeons has performed wrong-site surgeries.

[joeqsmith]

If you had flipped the lower components so the coupler was towards the front and detectors toward the rear, rather than the loops you could have used 90ish degree bends. 

[xrunner]

If you had flipped the lower components so the coupler was towards the front and detectors toward the rear, rather than the loops you could have used 90ish degree bends.

Yep several things could be improved. I will post pics of the finished input / output cable installation later. It ended up being tighter than I wanted but it will suffice for now. I may end up putting it in a larger metal case. I want to finish it as it stands and perhaps make an enclosure improvement as another step. Call this one an initial prototype. What else do I have to do?