CB and Ham Radio Techs Love Their Bird Wattmeters

[joeqsmith]

For cal factors,  I have to use the Signal Hound as a reference but its rated for 20dBm Max.  Adding attenuators is fine but I have no way to remove the error they add.   I can match SA and attenuators with the coupler, attenuators and detector side.   I can measure the attenuators on the VNA, but of course there's errors with that as well.  I really need a Bird golden standard to make any sense of it.


6:00 in, looks like he's a ham.  Funny story.

Well, that's 9:38 of my life I'll never get back----I gave up at that point!
So Ameritron are a pain in the butt,---big deal!
...

Most people are smart enough to use the skip and end.  .... Oh right!!   

[xrunner]

Well I must be smart then because I couldn't take more than two minutes of that.

I know people like that - they could take an hour to tell you about their trip outside to check the mail. 

[joeqsmith]

And yet, some of the "gee I'm offensive" heros get distinctly affronted if anyone questions their statements---go figure!

Where did anyone post YOU were offensive?   You're my hero!!      

[joeqsmith]

Well I must be smart then because I couldn't take more than two minutes of that.

I know people like that - they could take an hour to tell you about their trip outside to check the mail. 

Watch one of my hour plus meter beat downs, then you know what a long winded video is really like!!   

[vk6zgo]

Well I must be smart then because I couldn't take more than two minutes of that.

I know people like that - they could take an hour to tell you about their trip outside to check the mail. 

Watch one of my hour plus meter beat downs, then you know what a long winded video is really like!!   

But you don't have a really annoying voice!

[vk6zgo]

Oh that made my evening! There's nothing I can do now that can top that! 

I love the rendered "Bird meters", but rendered Nixies would be nice for the digital display.

[joeqsmith]

Moving the firmware filters up and then turning off the trigger delay in LabView.   This is about as fast as it's going to go without some major changes.   



I am guessing I could decode the audio in LabView similar to what I demonstrated with the LiteVNA.  Sound quality would be poor.

Link to original video. 

[bd139]

Hahahaha genuinely spat coffee all down myself this morning watching that 

[vk6zgo]

For cal factors,  I have to use the Signal Hound as a reference but its rated for 20dBm Max.  Adding attenuators is fine but I have no way to remove the error they add.   I can match SA and attenuators with the coupler, attenuators and detector side.   I can measure the attenuators on the VNA, but of course there's errors with that as well.  I really need a Bird golden standard to make any sense of it.


6:00 in, looks like he's a ham.  Funny story.

Well, that's 9:38 of my life I'll never get back----I gave up at that point!
So Ameritron are a pain in the butt,---big deal!
...

Most people are smart enough to use the skip and end.  .... Oh right!!   

I was hoping he would get to the point, so that's why I waited that long--if I had skipped, wouldn't it have just been more of the same?

[xrunner]

Moving the firmware filters up and then turning off the trigger delay in LabView.   This is about as fast as it's going to go without some major changes.   

Now that's what I call a watt meter! 

Beats the crap out of that coaxial dynamics USB job and it sounds better too!

[joeqsmith]

For cal factors,  I have to use the Signal Hound as a reference but its rated for 20dBm Max.  Adding attenuators is fine but I have no way to remove the error they add.   I can match SA and attenuators with the coupler, attenuators and detector side.   I can measure the attenuators on the VNA, but of course there's errors with that as well.  I really need a Bird golden standard to make any sense of it.


6:00 in, looks like he's a ham.  Funny story.

Well, that's 9:38 of my life I'll never get back----I gave up at that point!
So Ameritron are a pain in the butt,---big deal!
...

Most people are smart enough to use the skip and end.  .... Oh right!!   

I was hoping he would get to the point, so that's why I waited that long--if I had skipped, wouldn't it have just been more of the same?

Which point?  6:00 in he mentions he has been a ham for many years.  Being a ham, we know he likes to blab.  Scan to the end, we see it a half hour video.  Backup a few seconds with the slider and we see the story is just finishing up.  Took a whole few seconds to figure out it was going to be long. 

Now, why you feel the need to whine about it, that's going to take some time with professional help.   I'm not here to wipe your ass for you.     

***
Does seem a bit harsh but after a quick search, I'm sure your fine with it.   

https://www.eevblog.com/forum/blog/eevblog-302-electronics-beginner-advice/msg125899/#msg125899

[joeqsmith]

Moving the firmware filters up and then turning off the trigger delay in LabView.   This is about as fast as it's going to go without some major changes.   

Now that's what I call a watt meter! 

Beats the crap out of that coaxial dynamics USB job and it sounds better too!

Birds info
https://birdrf.com/en/Products/Sensors/Software-Applications/VPM3/VPM3-Virtual-Power-Meter.aspx



Typical CB/ham hobbyist review.  About 55:00 he finally shows it running.

WARNING vk6zgo, THIS VIDEO IS OVER ONE HOUR LONG!!!! 

[joeqsmith]

Looking over some of his other videos,  here he is reviewing an Anritsu MA24106A  which is another PC type. 

[metrologist]

I have that sensor. The MA24105A is applicable here.

and LoL

https://cbradiomagazine.com/power-in-perspective/

[xrunner]

I have that sensor. The MA24105A is applicable here.

and LoL

https://cbradiomagazine.com/power-in-perspective/

He says -

The numbers used were calculated using the inverse square laws for intensity and distance, and the commonly accepted rule of 6dB per S unit. I also had to use a baseline for a reference. That was that 4 watts of power will transmit 20 miles and be received with 1S unit. I can change these baseline values, but the curves stay exactly the same.That was that 4 watts of power will transmit 20 miles and be received with 1S unit. I can change these baseline values, but the curves stay exactly the same.

That wording is strange. 4 watts of power does not simply "transmit 20 miles" it radiates as far as it can out into space and beyond.

But ...

According to a link budget calculator, you would receive -52 dBm at the receiver for that set up. I had to estimate several things but they aren't going to make a big difference).

4W = +36 dBm
27 MHz
20 miles
I gave 0.0 antenna gains
0.2 dB loss for cables
Free space loss of 91 dB.

According to the documents an S meter reading of S1 will occur for a signal of -121 dBm into a receiver's 50 ohm antenna input.

For that scenario you would actually get a signal of -52 dBm at the receiver and result in an S meter reading of S9 + 20 dB (20 dB over S9). That is a very big signal.

But who knows how CB radio S meters are "calibrated"?   

[joeqsmith]

When I listened to the CB band a few weeks ago, I think the closest was within 100miles.  Most were much further. 

The name brands PC software all seem to allow you to graph the data.   So do I, but just a bit faster.   Here's what it looks like running full tilt.   


Original video

[xrunner]

Oh damn I'd give real money to see an actual Bird meter sitting right next to that virtual meter, reading an equivalent real-time power input of that music. 

[joeqsmith]

Oh damn I'd give real money to see an actual Bird meter sitting right next to that virtual meter, reading an equivalent real-time power input of that music. 

I could convert the linear values to the Bird scale easy enough and plot the forward power like the Bird so we could get an AB compare.   

We just need a Bird owner to make a video along with a link to the audio track they used.  They would need to use AM.   I could then run through the same audio track and sync up the two videos.   Any takers? 

Another option is if you found something one of the ham or CBers already uploaded, I could use that.     

****
A third order polynomial seems good enough.   If we don't want to get in a bar fight, we could go to a fifth.      

[mnementh]

Maybe they are sold for novelty use only.   Checking ebay, some nice photos of the workmanship.   

https://www.ebay.com/itm/195239166874?hash=item2d7529439a:g:f-cAAOSwgHNi1dyE

2-pill, 100-300W depending on...   Wonder how they cool it. 
https://www.ebay.com/itm/175351580759?hash=item28d3c4c857:g:Dc4AAOSw7DNi0EvV

Good lord... talk aboot giving you cancer just looking at it. 

I mean, I'm guilty of some pretty cringe ghetto-fab done for myself (that floated DPS1200FB server PSU stack is right up there)... but no way I'd try and get real money for any of it.

mnem
 

[Wallace Gasiewicz]

S meter on CB radios are NOT Calibrated.
When I fix one I set the S meter to about S7 for a S 9 signal -73 dBm.
The reason I do this is because 90% of the customers listen to relatively strong signals from close up radios.
No Complaints. Nice to see the needle move but not always peg.
Again most customers use CB for business applications (which they should not, according to Govt.) And they use relatively low power compared to the previous conversations. Basic communication,
S meters are notoriously inaccurate but useful. I have a measuring receiver that reads good dBm of Rx signal but I bet very few people have one.
Almost ALL S meters are inaccurate, The best you can do is set it to ONE S meter value, the others will be off.

Almost ALL Bird meters read RMS, some do peak, so comparing music or voice is not meaningful, unless you put in a measured one or two tone audio signal into the mic input of the transmitter.
Some better AM transmitters will have a very low carrier and really large side bands, some will not work without a big carrier.
I have a radio that generates an "AM" signal using only USB and a vestigial carrier. No one can tell the difference without a SA.

[vk6zgo]

For cal factors,  I have to use the Signal Hound as a reference but its rated for 20dBm Max.  Adding attenuators is fine but I have no way to remove the error they add.   I can match SA and attenuators with the coupler, attenuators and detector side.   I can measure the attenuators on the VNA, but of course there's errors with that as well.  I really need a Bird golden standard to make any sense of it.


6:00 in, looks like he's a ham.  Funny story.

Well, that's 9:38 of my life I'll never get back----I gave up at that point!
So Ameritron are a pain in the butt,---big deal!
...

Most people are smart enough to use the skip and end.  .... Oh right!!   

I was hoping he would get to the point, so that's why I waited that long--if I had skipped, wouldn't it have just been more of the same?

Which point?  6:00 in he mentions he has been a ham for many years.  Being a ham, we know he likes to blab.  Scan to the end, we see it a half hour video.  Backup a few seconds with the slider and we see the story is just finishing up.  Took a whole few seconds to figure out it was going to be long. 

Now, why you feel the need to whine about it, that's going to take some time with professional help.   I'm not here to wipe your ass for you.     

***
Does seem a bit harsh but after a quick search, I'm sure your fine with it.   

https://www.eevblog.com/forum/blog/eevblog-302-electronics-beginner-advice/msg125899/#msg125899

Joe, "Go piss up a rope!"

[bd139]

That song is an almost perfect test signal 

https://youtu.be/w7M3EEHYkJ0

Very CB 

[joeqsmith]

Joe, "Go piss up a rope!"

At least you bring the entertainment.  Sadly, not much else. 

[xrunner]

S meter on CB radios are NOT Calibrated.
When I fix one I set the S meter to about S7 for a S 9 signal -73 dBm.
The reason I do this is because 90% of the customers listen to relatively strong signals from close up radios.
No Complaints. Nice to see the needle move but not always peg.
Again most customers use CB for business applications (which they should not, according to Govt.) And they use relatively low power compared to the previous conversations. Basic communication,
S meters are notoriously inaccurate but useful. I have a measuring receiver that reads good dBm of Rx signal but I bet very few people have one.
Almost ALL S meters are inaccurate, The best you can do is set it to ONE S meter value, the others will be off.

I've checked and set S meters on lots of shortwave receivers and ham transceivers. Most of the "low end" shortwave receivers don't have accurate S meters at all. You can set up S9 for -73 dBm but it quickly goes out-of-cal above and below that. However my JRC NRD-535 shortwave receiver (very high-end) does have an fairly accurate S meter. Both of the ham transceivers I have now (Yaesu FT-450D and Icom IC-7300) have fairly accurate S meters. But no they aren't super-accurate over the entire range like some kind of lab-grade instrument.

But if the CB radios are as bad as the low end shortwave receivers then, yea, it's pretty meaningless. They should have just put a meter with no real "scale" on it so you'd get a relative signal strength. That's why that guy in the article I was responding to, saying some signal of "S1" on a CB radio means such-and-such as far as a receiving gauge, is nuts. 

[joeqsmith]

Showing a firth order fit to the virtual Bird meter.