CB and Ham Radio Techs Love Their Bird Wattmeters

[xrunner]

Here's how to fix your S meter - zap with negative ions!

[Wallace Gasiewicz]

Xrunner:

Yea. Almost all S meters are useful but not accurate.
To get a real reading you need to have a measuring receiver that costs maybe 10X what a regular HF radio would be.
Some radio service test set units have a pretty good ability to do this also.

[xrunner]

Here's what I've been playing with this 2nd round.

I have two OLED displays going now. They wouldn't work together at first using the Adafruit display libraries because of (what I was expecting) low memory. However I did get them working together with the U8g2 library - or rather a subset of it which saves memory. It doesn't use a buffer and writes directly to the display. However, it's very limited in what fonts you can use (monospaced). I wanted certain symbols too but part of the U8g2 library I had to use (U8x8) has a limited symbol set and most of them I have no use for.

I want more information presented is why I want two displays. The idea was to have the smaller display over the rotary encoder to show the settings it is controlling. These are the closest frequency step to the expected power emission and the step size of the frequency change. The larger one shows power (dBm and watts) or "Low Input PWR", the correction factor in use, and the voltage output from the AD8310. This is for my own interests and so I'm displaying what I want to see. 

Yesterday I ordered, among other items, an OLED display size I hadn't used before - 71 x 43 mm, 128 x 64. I may change to that one and in so doing can use the display library that I would prefer. It's not more pixels but the physically larger size will make it easier to see a screen full of info. Another item in the order is a rotary encoder with a threaded shaft. The ones I have now don't have that and so wouldn't be a great choice to mount through a hole.

As far as the Corr. Factor scheme, just about done with it.

(would like to replicate a Bird analog meter too if time permits      )

[Mark19960]

Xrunner:

Yea. Almost all S meters are useful but not accurate.
To get a real reading you need to have a measuring receiver that costs maybe 10X what a regular HF radio would be.
Some radio service test set units have a pretty good ability to do this also.

But! Wait!
This cheekie chappie right here:

https://www.youtube.com/c/FineTuneCBShop/

Will CALIBRATE your s-meter!
Because... there is apparently some sekret standard to calibrate one by and only he knows it!

I quote... from a video... because he adds this text to virtually every one:

Meter swinging over-modulated radios with a noisy receiver and miscalibrated S Meter have been Peaked & Tuned, comp-tuned or so-called Hi-Fi mods performed and misaligned by a Golden Screwdriver Magician .. not technician.

He sells s-meter calibration... and he fixes "noisy receivers" on brand new radios.
No, you "cannot make this stuff up"

 

[Wallace Gasiewicz]

There are various methods for fixing noisy receivers:
Turn down the gain
Turn on the noise reduction

Even Better:
Detune the radio
Disconnect the antenna

Turn the radio off, works every time.

Edit: In case you did not know peak and tune means removing a connection that limits Tx power and tuning the Tx coils, which are detuned purposefully at the factory
No big deal.

[Mark19960]

There are various methods for fixing noisy receivers:
Turn down the gain
Turn on the noise reduction

Even Better:
Detune the radio
Disconnect the antenna

Turn the radio off, works every time.

Edit: In case you did not know peak and tune means removing a connection that limits Tx power and tuning the Tx coils, which are detuned purposefully at the factory
No big deal.

I don't want to get too far off track here...
I have investigated everything he does... and it's all BS.
(below is specific to the one CB radio he works on)

That said.. the problem with Mark (Fine Tune CB) is that his "noisy receiver" fix is actually a modification to the AGC to reduce the gain of an opamp.
What it does is creates a situation where the AGC starts to engage late, and you get an overload in the second IF with a strong signal.
It also at times will take out the first RF amp stage on the radio.
Because the S-Meter signal is derived from the AGC, he then says the S-Meter has been "calibrated" as well.
That's because the S-Meter now requires a hotter signal to cause an indication... so thus the receiver is "quieter".
There is a lot more to this story.. like how it came to be and such but simply put, he copied the bad mod from someone else.

As to the "peak and tune" that's pretty much the term for removing/disabling the audio limiters causing a clipped AM envelope.
Most modern radios don't have detuned filters/L Matches, it's simply a control that you can turn now either in a menu or as a pot.

The bad AGC mod is a topic I plan on covering at some point.

[vk6zgo]

Joe, "Go piss up a rope!"

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

What's wrong?
That brings gales of laughter over on the TEA thread!

[joeqsmith]

Joe, "Go piss up a rope!"

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

What's wrong?
That brings gales of laughter over on the TEA thread!

With me? Nothing, but thanks for asking.  Sorry, I'm not familiar with the thread you mention. 

I added the 5th order fitter for the virtual bird meters to the main program along with a gain setting.   At least now what they show is somewhat meaningful.   The changes don't appear to have hurt the update rate too much.   



Christone “Kingfish” Ingram, 22nd Birthday Celebration

[metrologist]

If your modulation meter pegs before 200% it's no good. 

[xrunner]

Received the larger OLED display yesterday. Now I have real estate to work with.

It's supposed to work with SPI or I2C with reconfigurable jumpers. But of course I don't even need to state that it comes with no instruction sheet that tells which ones do what (except for a single one - R9). You might think that is the only one you have to jumper, but you would be wrong.

The seller has this on the Amazon page "SPI communication or I2C communication can be switched by configuring three resistors R3 R4 R5" But what about R9 - the one that's labelled to switch between ...  And are there any jumpers under the ribbon cable?   <------ YES! 

Fortunately I said to myself "Don't be stupid and trust these instructions". Looking elsewhere I found several people including The Defpom that had proper notes on the display. Geez - is it really that much trouble to include a piece of paper with the damn thing, or put the proper instructions on the seller page. I guess it is. 

Anyway - we'll test drive this thing today I hope.

[bd139]

Instructions would have cost two more attobucks and increased the liability of the seller.

If you want some instruction fun, try buying an AM radio kit on aliexpress. The instructions are probably entirely wrong 

[xrunner]

Instructions would have cost two more attobucks and increased the liability of the seller.

If you want some instruction fun, try buying an AM radio kit on aliexpress. The instructions are probably entirely wrong 

A little rant, but really ... I wonder where that comes from - just not putting a piece of paper in the box. I mean they did label one jumper on the board. What's to prevent doing it for the others? Is it really attobucks? The amount of ink saved results in 0.00234 x 10^-57 dollars so we save good money in 1000 years. It's some attitude I don't understand I guess.

Why not adopt the Keysight approach and charge for the answers? 

Sorry ... 

[bd139]

 I wouldn't try rationalising Chinese drop shipping, packaging or documentation mechanics. 99.9% of them have no idea what they are selling or manufacturing, just that it makes money if they follow a set of steps 

[joeqsmith]

If your modulation meter pegs before 200% it's no good. 

Is that one of those ham things, like RMS power?   Currently I do a point slope from the average to 0.   Anything below 0 would be free energy. 

[joeqsmith]

Ham's using their Bird to measure some coax. 

[joeqsmith]

Another CB amp channel with their Bird, well, he talks about slug BS.  Looks like most of his vids after this show the CD meter.   The best part of this video is the solder splatter on his distribution strip.       I got a Tektronix 50MHz current probe for free that looks like this guy may have owned it.   Solder was splattered all over the case.   

[xrunner]

Another CB amp channel with their Bird, well, he talks about slug BS.  Looks like most of his vids after this show the CD meter.   The best part of this video is the solder splatter on his distribution strip.       I got a Tektronix 50MHz current probe for free that looks like this guy may have owned it.   Solder was splattered all over the case.   

Yea the dude sticks his hand in the back of that amp and starts touching components ... wearing a ring on his finger.

[joeqsmith]

How about a metallic purple custom painted Bird. 

https://youtu.be/sB43yCpZ8RM?t=29

Maybe an aftermarket PC interface for the Bird.   Looks fastest than the pro setup.   So he's measuring the reflected power and nailing the meter??

https://youtu.be/8TsSzTbIykM?t=301

[xrunner]

Looks like they make some pretty nice products -

https://www.metropwr.com/

I got the larger OLED display working. I might have more fun with that than the actual power meter. 

[bd139]

Not a bad display that 

Found a couple more old projects related to this...

The "pikey load". Caddock FTW



NanoVNA VSWR plot



And found a shit load and power sensor I made for something.



Think I have a load problem. I don't own no stinkin' birds though 

[xrunner]

Not a bad display that 

Yea this is gonna work out great. I should have looked harder for alternates before. I've been playing with the formatting for what I want for a couple of hours because it opens up so much more possibilities. It is the same pixels as the smaller ones (128 x 64), but man, you can get so much more on it because what would have been almost microscopic on those tiny ones is actually very readable on this one. Be a little bit of a challenge to get the board on a front panel for the same size case but I think it will just fit.

Did you say a while back you ordered another log amp to play with? Seems like you said you did.

[vk6zgo]

If your modulation meter pegs before 200% it's no good. 

Is that one of those ham things, like RMS power?   Currently I do a point slope from the average to 0.   Anything below 0 would be free energy.

I always thought RMS power was an audiophile thing!

"Zero" modulation in Mod Mon talk just means no modulation, so at 0% mod you still have your original unmodulated carrier.
Just looking at a reading of zero on the modulation meter on a Mod Mon tells you nothing about whether the transmitter is producing power or not.

Power meters like the Bird show a standing reading when the Tx is unmodulated, so are not useful for, nor are they used to display, modulation.

In conventional AM, the modulating signal is symmetrical, so the 100% limit is when the negative excursion of the modulating signal cuts the carrier.
In practice, AM Broadcast stations are limited to around 90% modulation, to avoid this.

It you "cut carrier" on the negative excursions of modulation, your mod mon will "peg", but you don't produce any more power out.
In practice, you waste a lot in harmonics, everybody on multiples of your transmitting frequency will be upset, & the Licencing Authority will kick your butt severely!(If you are a broadcast station, an aeronautical station, or a ham---CBers are seemingly ignored).

Strangely, listening to the result on an AM receiver tuned to the original frequency, the distortion is not really apparent, but looking at it with an Oscilloscope (modulation envelope), or with a Spectrum Analyser, the problem is readily apparent.

But you know all this crap & are just playing dumb for some unknown reason!

[vk6zgo]

How about a metallic purple custom painted Bird. 

https://youtu.be/sB43yCpZ8RM?t=29

Maybe an aftermarket PC interface for the Bird.   Looks fastest than the pro setup.   So he's measuring the reflected power and nailing the meter??

https://youtu.be/8TsSzTbIykM?t=301

Come on Joe, you know better than that!

Birds are symmetrical ---they don't care which coax port is source & which is load, as long as you have the slug oriented correctly.
In this case, the coax from the Tx is on the right, with the load on the left.

Why did he do it that way round?
Who knows?----Maybe he is left handed, or maybe has too much clutter on his bench to do it the other way round?

[joeqsmith]

But you know all this crap & are just playing dumb for some unknown reason!

Why would you waste so much time blabbing on and on then?  Oh right!   

[joeqsmith]

 

Looks like they make some pretty nice products -

Looks like their high end setup would be less than a new Bird.   The hams would still want the Bird and pile of slugs.