CB and Ham Radio Techs Love Their Bird Wattmeters

[Kosmic]

I wonder if those HT antennas are monopole. If it's the case then the ground plane would be in the device and thus not included in the test when connected to a NanoVNA. Might explain the bad results when testing the antenna alone.

Now is the ground plane really useful for transmission ? i'm not sure.

[joeqsmith]

Ham using "science" to compare some antennas.  At first, I thought oh no, here we go again.  Then he surprised me by actually taking  them on a road trip and puts them to use at  2 & 4miles.   He talks about the few who live in their scientific bathtub with their NanoVNA toward the end and cries BS.   

I think if I were reviewing hand held radio antennas, this is exactly what I would do or at least it would be a big part of the evaluation.   

If I were trying to show someone how to construct antennas and trim them,  most likely I would have some sort of bridge in my bathtub as a starting point.       

https://youtu.be/k-fkcgpGuOM?t=837

[vk6zgo]

Ham using "science" to compare some antennas.  At first, I thought oh no, here we go again.  Then he surprised me by actually taking  them on a road trip and puts them to use at  2 & 4miles.   He talks about the few who live in their scientific bathtub with their NanoVNA toward the end and cries BS.   

I think if I were reviewing hand held radio antennas, this is exactly what I would do or at least it would be a big part of the evaluation.   

If I were trying to show someone how to construct antennas and trim them,  most likely I would have some sort of bridge in my bathtub as a starting point.       

https://youtu.be/k-fkcgpGuOM?t=837

Certainly a nanoVNA, or some sort of bridge is something I like to include in my "bathtub", to at least know what the antenna "looks like" to the source.

Other characteristics are dependent on a whole raft of other things, so measuring the received signal level at a "remote" point is definitely a good idea, at least for VHF/UHF stuff, especially antennas on handheld radios.

It gets a bit messy with HF, where the desired angle of elevation of the radiated signal might mean that much of the signal is not well received at a relatively close "remote" point, & the azimuth pattern is also different at ground level.

I was initially surprised that his signal drops out at around 4 miles, but looking at the topography around his station, I can see why.
I have definitely done better with handhelds where I live, but, although looking down from the Darling Escarpment, the coastal plain
looks "as flat as a pancake", up close, there are many high points which help a lot.

[xrunner]

Bird 43 rackmount. If you want Big Iron here it is. Carrier / Sideband using two slugs.

[Chat GPT]

Bird watt meters have been a trusted and reliable tool for measuring RF power for many decades, particularly in the CB and ham radio communities. They are known for their accuracy, durability, and ease of use. While there are now many other brands of watt meters available, Bird remains a popular choice among many RF professionals and enthusiasts.

[xrunner]

Bird watt meters have been a trusted and reliable tool for measuring RF power for many decades, particularly in the CB and ham radio communities. They are known for their accuracy, durability, and ease of use. While there are now many other brands of watt meters available, Bird remains a popular choice among many RF professionals and enthusiasts.

You say they are known for their accuracy, but you didn't say what the accuracy was, or which Bird wattmeter you were claiming was known for this accuracy. Can you tell us these figures if you know them?

[joeqsmith]

Bird watt meters have been a trusted and reliable tool for measuring RF power for many decades, particularly in the CB and ham radio communities. They are known for their accuracy, durability, and ease of use. While there are now many other brands of watt meters available, Bird remains a popular choice among many RF professionals and enthusiasts.

You say they are known for their accuracy, but you didn't say what the accuracy was, or which Bird wattmeter you were claiming was known for this accuracy. Can you tell us these figures if you know them?

    No ones going to touch that one!

[metrologist]

The Bird 43 wattmeter was released more than 70 years ago. What else were you going to use back then?

Power Range: 100 mW to 10 kW (using Bird® Plug-in Elements)
Frequency Range: 450 kHz to 2.7 GHz (depending on element)
Insertion VSWR: 1.05 max. to 1000 MHz (with N Connectors)
Accuracy: ±5% of full scale

https://birdrf.com/Products/Test%20and%20Measurement.aspx

[xrunner]

The Bird 43 wattmeter was released more than 70 years ago. What else were you going to use back then?

70 years ago? That's exactly what I would use ... 70 years ago. 

Power Range: 100 mW to 10 kW (using Bird® Plug-in Elements)
Frequency Range: 450 kHz to 2.7 GHz (depending on element)
Insertion VSWR: 1.05 max. to 1000 MHz (with N Connectors)
Accuracy: ±5% of full scale

https://birdrf.com/Products/Test%20and%20Measurement.aspx

Yea I am very aware of those specs - what I wanted to know was if the entity posting, now known as Chat GPT, (and banned) knew it. That account was another name until the mods found out and renamed it to Chat GPT because that's where the text came from (unattributed to ChatGPT). But of course they never responded because they were too lazy to even ask ChatGPT for the specs. The account also made other posts on this forum that came from ChatGPT. That's the point of me asking them what the accuracy was. There are accounts being made here that are simply making posts that come out of ChatGPT and it's going to become an increasing issue in the months and years ahead.

[vk6zgo]

The big feature of Bird Wattmeters is not absolute accuracy, but rather repeatability.

In commercial use, I have mainly seen them in use as in-line indicators in installations where the original tests would have been done with much more accurate (& expensive) equipment.
The Bird Wattmeter was then placed permanently in line, & its readings recorded.
If it is reading high or low by a particular amount, it is very likely to still have the very same error in 20/30 years' time.

A Tech can visit a site, quickly check the reading on the "Bird", & if it hasn't changed, be reasonably confident that there is nothing amiss.
if it reads differently, it is time to "bring out the big guns".

Ultimately, some of these Wattmeters reach the Amateur Radio market, where they are prized because of repeatability.
Although some of the similar devices built for that market, & indeed, the CB one, offer similar accuracy, they are "built down to a price point" & due to poor mechanical design & bad soldering may fail in a relatively few years.

Of course, you know all this, but no matter how many times you tell it, Chat GPT will never know, as it treats every question as if it was the first time it was asked, & does not learn from interactions.

[joeqsmith]

Saw what appears to be a vintage Bird for sale.   

https://chambana.craigslist.org/ele/d/georgetown-watt-meter/7600931469.html

[xrunner]

Yea may be vintage.

But wait ... I see a Coaxial Dynamics slug in that thing. Isn't that considered blasphemy? 

[vk6zgo]

Yea may be vintage.

But wait ... I see a Coaxial Dynamics slug in that thing. Isn't that considered blasphemy? 

Nope! They are totally compatible, so it is done regularly.
I wonder which is the "clone"?

[pienari]

Meters and meters.
When i started to build rf amplifiers i used several different brand instruments because all was showing different results.

But after i bought digital oscilloscope i made 10:1 sample att to 50ohm ant line.

Today i can make 100% accurate measurements.

Just check voltage and go to
https://www.random-science-tools.com/electronics/dBm-Watts-volts.htm

You will get Average power.

[xrunner]

Today i can make 100% accurate measurements.

Really?  

[joeqsmith]

You're such a doubter.   

[xrunner]

Was speaking with a local ham a few days ago about his effort to calibrate a Daiwa cross-needle power/SWR meter. If you don't already know, this type of meter reads forward and reflected power and SWR. By observing where the needles cross, and the markings behind this crossing point on the faceplate, you can read the SWR (approximately).

I said I have one also - a CN-103 (his was a different model) and I'd calibrated it before. We got to talking and he wondered if they could be "converted" to a digital read-out. I said I didn't see why not, but it sounds interesting and I'd think about it as a project.

So I'm thinking about it. I got the schematic and I want to make some measurements of the voltage range that the meter movement is receiving from the detected RF in this Daiwa design. I don't think I'll even need to be worried about the range switch - that is in there because they are using mechanical meter movements.

Also, if I do it, I'd want it to be 100% accurate too. 

[joeqsmith]

Is Daiwa in Japanese spittoon?

[xrunner]

They're into sport fishing now it seems -

https://daiwa.us/

[joeqsmith]

Looks more like chewing tobacco than lake water.

[xrunner]

Any and all dried fluids and scratches will be attributed to my cat. 

[joeqsmith]

Fish, pussies and dribble.   Are we back on BD139's floozies or Watt meters?

[xrunner]

Wherever you want to go - I'm busy answering your inquiries about spittoons and lake water. 

[joeqsmith]

Is your friend with the Bird planning to have you add digital to their meter as well?

Keep thinking I should get some sort of high end hamish Watt meter and do some sort of shoot out with it. 

***
Maybe something like this:
https://static.dxengineering.com/global/images/instructions/mwr-fx775-fx3.pdf

With the PC interface, we could compare screen update rates.   

[seedkey]

Dem are bird watts