CB and Ham Radio Techs Love Their Bird Wattmeters

[joeqsmith]

Hey Joe (sounds like a Jimi Hendrix song),

From a viewer

heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go
I'm gunna stuff that old meter
stuff that old meter into a garbage can
cause that's where it belongs
hey joe, I heard you fried your best meter to a crisp
you fried it to a blackened crisp
yeah
yes I did, I fried it to a crisp
you know that meter was such a peace of shit
and I gave it the zap
and I fried it
Alright
Zap it one more time again, baby

[joeqsmith]

... spent all my money on beer and floozies instead

Let's see, spend the cash on a gray box that just sits on a shelf or a good looking lady.  IMO, you made better use of funds. 

On the actual build I managed to get a calibration routine in the code which was fun. You put a 0dBm reference in it and held the button down for 3 seconds and it recorded the reference ADC value. Then you put a known good 10dB attenuator in and press the button again and it calculated slope, intercept and stored it in flash on the MCU. I still have the code around somewhere. Will dig it out when I can be bothered (not now)

I want to see how stable it is with load, frequency, power.  That's a long way off.   

[joeqsmith]

You know we'll have it easy though, because we won't have to write the software. Yea it's true go see here -

https://www.eevblog.com/forum/chat/video-ai-that-generates-code/msg4234603/#msg4234603

All you have to do is explain what you want to the AI. You'll look like a genuis! Simply fill in the blanks below -

Hey AI! I want software to run a power meter using the AD8310 IC, running on platform ______ , and using a display of type _______.

Thank you.

Cool thing is you don't have to tell anyone the AI wrote it!

 

It requires a cell phone to authenticate.  Landlines are not supported.  Oh well.

[A.Z.]

You know we'll have it easy though, because we won't have to write the software. Yea it's true go see here -

https://www.eevblog.com/forum/chat/video-ai-that-generates-code/msg4234603/#msg4234603

All you have to do is explain what you want to the AI. You'll look like a genuis! Simply fill in the blanks below -

Hey AI! I want software to run a power meter using the AD8310 IC, running on platform ______ , and using a display of type _______.

Thank you.

And the AI after a bit of processing will show an eBay link to buy a used Bird wattmeter

[bd139]

That sounds like my eBay script. It finds things that are worth more than they are selling for 

[xrunner]

When I get the AD8310 board I want to try to see how well it performs based on the datasheet graphs. I created a spreadsheet and manually entered data to create the same curve as the one showing plots of 10, 50, and 100 MHz inputs. Just one line is fine for this test. My X scale is dBm (no dBV). When I get the board I can record data for these three frequencies and see how well the match is

As always if it works out, as we told our bosses "The experiment was configured to achieve the desired results"

If this does not happen, all testing will be cancelled due to lack of funding, blamed on coronavirus, etc. 

[vk6zgo]

You know we'll have it easy though, because we won't have to write the software. Yea it's true go see here -

https://www.eevblog.com/forum/chat/video-ai-that-generates-code/msg4234603/#msg4234603

All you have to do is explain what you want to the AI. You'll look like a genuis! Simply fill in the blanks below -

Hey AI! I want software to run a power meter using the AD8310 IC, running on platform ______ , and using a display of type _______.

Thank you.

And the AI after a bit of processing will show an eBay link to buy a used Bird wattmeter

Or it will say, "Hang your DMM across the DC output of the device, write the reading down, grab your 30 year old calculator & work it out, you lazy bum!"
"Do that a few times, & you can make a nice Excel graph to save doing that work next time."

[joeqsmith]

When I get the AD8310 board I want to try to see how well it performs based on the datasheet graphs.

I ended up ordering a few different demo boards.  The <$20 compared with >$300 on Digikey drove me to it.     I'm assuming the parts are a knockoff and agree, step one, compare them with AD datasheets.   Well, after reverse engineering and modifying the board.   I did pick up the same boardish that you plan to order so we can at least have two data points.     

While searching for information on the Bird, it seems they had outsourced much of that to China and the movements are having problems.      Worse, it seems warranty is also a problem?   Maybe like Keysight, they don't sell to the CB and hams....

[xrunner]

While searching for information on the Bird, it seems they had outsourced much of that to China and the movements are having problems.      Worse, it seems warranty is also a problem?   Maybe like Keysight, they don't sell to the CB and hams....

Reminds me of some padlocks I bought last year. The brand is "American Lock" but are they made here? Of course not - "Made in Mexico".

I ended up ordering a few different demo boards.  The <$20 compared with >$300 on Digikey drove me to it.     I'm assuming the parts are a knockoff and agree, step one, compare them with AD datasheets.   Well, after reverse engineering and modifying the board.   I did pick up the same boardish that you plan to order so we can at least have two data points.     

The accuracy of the chip is actually pretty decent if you believe the datasheet. I should get it today, but I need to fix the input impedance because they put a 100 ohm R there to be in parallel with the internal 1k. The sheet says that 1k ohm is "typical" but it has a range of 800 to 1200 ohms. I think know what to do since it already has a 100 ohm SMD soldered in-place ...

If it works right I think I'll put it in a project box. I think it would be a good tool for quick sanity checks of your RF signal gen. or other low power RF (+17 dBm or 50 mW Max). I don't think I'll go beyond that purpose because I have better equipment for higher powers. But yea, for a low power RF measurement device it seems like a decent thing to have. If you want to make something even more capable then it looks like a good part to build your project around (if it works). bd139 played with it and he didn't seem to think it was a crappy part or he would have alerted us (I think  ).

We will see ... 

[bd139]

If I thought it was a crappy part there would be a few pages of rants 

It's reasonably priced for the capability, works well and has very few footguns. What more can you ask for

[joeqsmith]

The comments are pretty good. 

https://www.iz2uuf.net/wp/index.php/2017/07/29/the-myth-of-reflected-power/

I had stumbled onto an old bridge or something that had various mismatched loads.  While trying to find it again, I came across this old gem.   Outside of it matches the grid dip meter I have and would like nice sitting next to it, it would serve no purpose.   Still, I've made worse purchases.    

https://www.ebay.com/itm/255396042281?hash=item3b76ca5629:g:zJ0AAOSwZ~9iEi~g

[joeqsmith]

Growing up, I remember seeing TV shows where the owner is banging the side of the cabinet to get it to work.  Hams repair their Bird meters in much the same way. 

[xrunner]

Well I got it today. Be checking it out tomorrow after I add another 100 R in parallel to the existing one.

The company name is "HiLetgo".

Seems I remember dating a girl that said that to me on the first date. 

[bd139]

That looks hookier than my board 

[A.Z.]

Growing up, I remember seeing TV shows where the owner is banging the side of the cabinet to get it to work.  Hams repair their Bird meters in much the same way. 

Nope, that isn't a repair, that's how to CALIBRATE an old Bird meter

[joeqsmith]

Growing up, I remember seeing TV shows where the owner is banging the side of the cabinet to get it to work.  Hams repair their Bird meters in much the same way. 

Nope, that isn't a repair, that's how to CALIBRATE an old Bird meter

Align?  No need to calibrate it as I'm guessing if the power reads higher than previous, it's a job well done.   Of course, if they bang the whole meter, it may explain why people are posting about the Chinese movements failing.   

[joeqsmith]

Video showing proper repairs.  Alignment starts around 19 minutes in. 

[xrunner]

That looks hookier than my board 

Hey come on! It's got a red LED for "power on". I got my money's worth! 

[bd139]

That looks hookier than my board 

Hey come on! It's got a red LED for "power on". I got my money's worth! 

Damn I should have put a go faster light on mine 

[xrunner]

LOL Joe where are you finding these gems? 

We should be working on our power meters but I'll review it because you went to all this trouble.

OK my critical review:

I like the weathering on the meter case - they charge a lot of money to do that to furniture. Deep gouges to bare metal helps the patina over time. This is also demonstrated when he takes apart the elements and points to the rust with the screwdriver a excuse me the "alignment tool".

Background music isn't too bad. 

Also love the red coax, it's all the rage these days. And electrical tape as a strain relief, we should all take notes.

He does have cleaning cloths available ... OK he never used one but they are available.

Also you correctly said the alignment starts at 19 minutes ... technically you are right, he is aligning it. But inquiring minds want to know ...

TO WHAT !

To the transmitter probably, since it put out 100 W a few years ago then it's a simple matter to put the needle back where it belongs. Maybe a little more to impress your friends.

I doubt there is a problem with it any of his methods, the language barrier is all that's preventing me from understanding that it's all being done correctly. Gee Joe I was going to show pics of my testing here but now I'll be to embarrassed for anyone to see my bench, are you heppy now?

[joeqsmith]

I hand picked a few carbon comp resistors to use a mismatched loads to test my Watt meter if I get that far.   These are only rated for a couple of Watts but good enough for a basic checkout.  I made one for 1,1.5,2 & 3.  Pulled out my childhood VSWR meter and tried them out.  Meter isn't exactly what you would consider accurate.    Quick search and this owen guy comes up again.     They must be a popular ham.

https://owenduffy.net/transmissionline/VSWR/vmhsl.htm

With the Bird meters, you are going to use two slugs, one for forward, one for reverse to keep you close to the highest reading.  Then you have the error of these two slugs...  I wonder if it's any closer than my childhood meter.  Say $100 per slug plus the meter... and you need to calculate the ratios.  Maybe Bird supplied a slide rule? 

[joeqsmith]

Going with a Blue LED added too much cost. 

Saw those taped up cables that looked like the wrong connectors were on them.    Here's my new metrology grade mismatch standards and aligator test cable, and my red coax.   Mine serves as a constant reminder that when I have it out, I am working with high voltages because I need a reminder like that....

[joeqsmith]

...

Also you correctly said the alignment starts at 19 minutes ... technically you are right, he is aligning it. But inquiring minds want to know ...

TO WHAT !

This person explains the importance of having a Watt meter reference.   I assume that the only reference good enough would be another Bird meter.

[xrunner]

Made this a few years ago when I needed to check the SWR meters in HF rigs. Works well. RF load resistors from commercial equipment off Ebay.

[joeqsmith]

Made this a few years ago when I needed to check the SWR meters in HF rigs. Works well. RF load resistors from commercial equipment off Ebay.

I used RFP RM250-50s in my coupler bolted to the case to conduct that massive 2W of heat.   Sure it's frequency specs are also just a tiny bit overkill for 30MHz.   Braid is soldered to the stripline  to insure poor frequency response.