CB and Ham Radio Techs Love Their Bird Wattmeters

[vk6zgo]

Well, CW measurement is a very limited use case, isn't it.

No it isn't.

It reads average power, which is also the standard way of measuring AM & FM power.
Most analog power meters you might use on your bench, like the Bird, & many others, are really RF voltmeters calibrated in average power.

Their readings will vary with modulation both on SSB & AM. (although not accurately)

Traditionally, high power Broadcast & Comms transmitters used thermocouple ammeters to read RF line current.
By their nature, such devices respond to the average current, so when some manufacturers installed power meters, those particular meters were not only designed to respond to an average (in this case, of power), but also to ignore the instantaneous variations in modulation, similarly to the thermocouple meters.


SSB does need Peak Envelope Power meters, but speech & music waveforms are chaotic, so a device responding to all the different peaks would be difficult to make, & to read.
 
In practice, analog power meters which offer PEP measurement use a fixed CR time constant following the detector, & their PEP measurements are really only accurate with some of the digital signals often used by hams, or with fixed tones.

A type of transmission where the traditional CR time constant "peak & hold" circuit is useful is analog TV, where the meter reads the"sync tip" power, which is maintained at a constant level, no matter the level of the video signal betwen the horizontal sync pulses.

[Bud]

...  i am asking to compare the project meter against watever industrial RF power meter you have on hand, including the Bird one.

Yeah Xrunner,  show us that Bird meter you covet!!!   

In other words, you are unable to run a side to side test, hiding behind ridiculing emoticons.

[vk6zgo]

  From these few comments, you may reasonably conclude I am a dumb fuck and the only reason I continue to work is people feeling sorry for me.  I'm perfectly fine with that! 

On the contrary, Joe, you are a very clever guy,---- it is just your Jihad against hams & Bird meters that is annoying.

Unless you have come to the conclusion that there are similar religious and or cult behaviors when it comes to ham radio and Bird meters, it seems like a poor choice of words.  Even if that was your intent, I have little interest for anything related to organized religion. 

https://en.wikipedia.org/wiki/Jihad

I rather thought that  the "anti-ham/Bird" thing was the cult like behaviour.

It's interesting that you never call me out for picking on the CB group.  Rather, you tend to join.

Coming from an Australian perspective, it is bit like laughing at Dodos, as CBers are all but extinct in this country.
I can't say I have come across a CBer for a decade or more------I do seem to remember firing up an old SSB CB & having a quite civilised conversation with a couple of oldtimer CBers on CH35 LSB back in 2006 or so, but even then, that was "the only show in town" on 27MHz.
Back in the 1970s, they were "wall to wall, & ten feet tall"!

It's funny how the two groups have similar behaviors on the air (when if comes to how they treat one another) but how hams have such a need to downtrodden the CB group.  It's very possible that CBers look upon the hams in much the same way but I just can't tell what it is they are saying.   

I can't see the ham radio use case for continuous inline connection of such a meter as shown in the video.

The idea is that you show this off to your fellow hams in order to advance your tech status within the group.    Perhaps seeing the needle bounce to the command of their voice appeals to their need to be in control of something??  Hard to say.       

...using analog circuits they somewhat ambitiously styled as "computers".

Early computers were humans and later analog.  It was the first application for operational amplifiers.  You like to talk about the old tube broadcast equipment you worked on.  I have a copy of book given to me by an old German friend which details making analog calculations with tubes.   I had the opportunity to meet a gentleman who worked on the early drum memory.  I have some of their papers on early analog computers as well.

[bd139]

...  i am asking to compare the project meter against watever industrial RF power meter you have on hand, including the Bird one.

Yeah Xrunner,  show us that Bird meter you covet!!!   

In other words, you are unable to run a side to side test, hiding behind ridiculing emoticons.

I’m tempted to buy one just so I can do a side by side test.

But I don’t want to dirty myself.

I don’t need one though. My house has central heating.

[vk6zgo]

...  i am asking to compare the project meter against watever industrial RF power meter you have on hand, including the Bird one.

Yeah Xrunner,  show us that Bird meter you covet!!!   

In other words, you are unable to run a side to side test, hiding behind ridiculing emoticons.

I’m tempted to buy one just so I can do a side by side test.

But I don’t want to dirty myself.

I don’t need one though. My house has central heating.

Birds are passive, so they don't create more than a microsopic bit of heat of themselves.

You would need to have a test load instead of a power attenuator, either of which would dissipate near as dammit all the applied power.

[joeqsmith]

...  i am asking to compare the project meter against watever industrial RF power meter you have on hand, including the Bird one.

Yeah Xrunner,  show us that Bird meter you covet!!!   

In other words, you are unable to run a side to side test, hiding behind ridiculing emoticons.

   Most, if not all of what I have shown was some sort comparison.   Guessing it all just went over your head was all.   

[joeqsmith]

I rather thought that  the "anti-ham/Bird" thing was the cult like behaviour.

To the extent the thread is cultivating and attempting to educate, it is. 

... I passed a group of the "New Generation" of hams lounging outside the entrance....

Old hams putting down the newer ones does seem to be another pattern.   Of course, I'm no better as I treat the old hams with their golden Bird meters much the same way. 

[bd139]

Old hams putting down the newer ones does seem to be another pattern.

I'm just trying to rock the see-saw back to the middle on that one

[vk6zgo]

I rather thought that  the "anti-ham/Bird" thing was the cult like behaviour.

To the extent the thread is cultivating and attempting to educate, it is. 

You don't have to educate me---I know your meter is more accurate than a Bird.
I also know, that in most cases, it doesn't really matter.

... I passed a group of the "New Generation" of hams lounging outside the entrance....

Old hams putting down the newer ones does seem to be another pattern.   Of course, I'm no better as I treat the old hams with their golden Bird meters much the same way.

Many new hams are eager to learn, but there is a minority group who know nothing, & are reluctant to learn.
I have put down such people in my comment, on behalf of people who know what Oscilloscopes do.
Interestingly, I don't know any hams with Birds, old or new.

[xrunner]

I never knew a thread about power meters could be so dramatic. And people think electronics is boring. 


Look out Bird there's a new power meter player in town! 

The project meter (AD8310 based meter) was compared to the measurements of an hp 437B (an industrial RF power meter) using an Agilent 8482A (an industrial RF power sensor. The 8482A sensor cal points have been correctly entered into the 437B and I have verified it reads accurately using my Agilent 8648A (an industrial RF signal generator).

The RF transmitter was a Yaesu FTM-100D using the low, med, and high power settings. These correspond to the 5, 20, and 50 W levels of the radio. I din't expect it to output exactly those powers, all I need it for is comparing a known accurate measurement to my project meter. The output was attenuated by 50 dB (verified) before entering the power meters.

The results can be seen in the attached plots. I must say I'm quite impressed with the AD8310 part from Analog Devices. Once you get the required cal constants figured out, and get the Vo converted to dBm or Watts, it works very well as a power meter for calibrating radio transmitters. Quite usable in my opinion.

[joeqsmith]

You don't have to educate me---I know your meter is more accurate than a Bird.
I also know, that in most cases, it doesn't really matter.

It wasn't my goal to attempt to educate you personally.  I can understand you feeling the thread is all about you.  Outside of my SA, I do not have a meter.   

Many new hams are eager to learn, but there is a minority group who know nothing, & are reluctant to learn.
I have put down such people in my comment, on behalf of people who know what Oscilloscopes do.
Interestingly, I don't know any hams with Birds, old or new.

It seems many old hams also fit that group.  The tests will certainly bias the pool of new members.  If the government wants more technical members, they just need to raise the bar.   Old ones have already learned everything there is to know.  They are experts in their circle of fellow hams.   

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[joeqsmith]

The two 10's showed up today.   

Working on the DAS.  Shown connected to my Fluke standard.   About 100uV of noise with the current setup.   

Connecting both channels to the arb and simulating the full scale at 10Hz.  Doubt the Bird's mechanical movement is that fast.  Should keep up with the PC link shown in that last video I linked. 

[vk6zgo]

You don't have to educate me---I know your meter is more accurate than a Bird.
I also know, that in most cases, it doesn't really matter.

It wasn't my goal to attempt to educate you personally.  I can understand you feeling the thread is all about you.

Similarly, both you & xrunner tend to take any contrary comments as personal affronts!

  Outside of my SA, I do not have a meter.

My bad, I was thinking of xrunner's meter, & had already posted when I realised my mistake.
I then hoped you did have a meter.

That said, if I had an SA, I would also probably not worry about a meter.

With one, I could characterise my junk box directional coupler, as I did before, when my last job was very "thin on" for test gear except for the SA (with tracking gen) & originally, a crap "Meterman" DMM, replaced later by a decent Fluke one, so just about anything else was stuff the other guy & I brought from home.

Oh, wait!
They did have a Bird!----, plus a MFJ 269 antenna analyser, which was used to check the antennas (they didn't radiate outside the screened room, so maybe should be called "transducers")

They also had some decent test loads, so with the SA & my directional coupler, I could tune up the individual RF amps which were combined to get the required RF output.
The manufacturer didn't bother, so we were stuck trying to do stuff we hadn't been prepared for.

All the information about my coupler was in their (long gone) files, as I didn't think to make a copy for myself.

Many new hams are eager to learn, but there is a minority group who know nothing, & are reluctant to learn.
I have put down such people in my comment, on behalf of people who know what Oscilloscopes do.
Interestingly, I don't know any hams with Birds, old or new.

It seems many old hams also fit that group.

Oh, hell, yes!
There are a goodly number of "silly old farts" around, who mostly started out as "silly young farts", or "silly middle aged farts" & didn't improve over time.

  The tests will certainly bias the pool of new members.  If the government wants more technical members, they just need to raise the bar.   Old ones have already learned everything there is to know.  They are experts in their circle of fellow hams.   

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format

Most of my "circle" as far as one exists, is made up of old farts who are either still involved with Electronics in some form or the other, or retired from that field.

[xrunner]

Similarly, both you & xrunner tend to take any contrary comments as personal affronts!

Well I'm still recovering from being around the local hams which did the same thing. 


I did go into the service menu of the FTM-100D to set the power output levels as specified in the service manual. I did not set them to the values of the specifications given in the user manual. Why? Because some of the values are different between the two sets of numbers. That's right ...

For example, for UHF @ 440.050 per the service instructions, you set the low power not to 5.0 W (as the specs say in the owner's manual) but to 5.3 W and for the VHF @ 146.050 the high power is set not to 50 W but to 48 W. If you wanted to ignore the service manual, you can also keep adjusting it up, but I didn't choose to do that. All the adjustments are to +/- 0.5 W.

As I suspected, the UHF high power will not adjust to 50 W but only about 40 W. This is not really unusual as I've seen this on other Yaesu transceiver models in the UHF band that have been in use for several years. So that does not meet specs and the cure is to replace the output PA part. But since this is going back in the closet I really don't care.

In any case, I took two pics when I was in the service menu and setting the UHF med. power to 20 W +/-0.5 W per the service manual. Both power meters can make these adjustments easily and accurately.

[bd139]

I think most Yaesu kit power output is “aspirational”. I managed 5.1W out of my 6W rated FT818 new out of box  . Made contacts with that and a shite antenna so not overly bothered. The bit that’s worth paying for is the receive chain.

I suspect from looking at the designs that the output match is “good enough for a 1.5:1 and meh”

[xrunner]

Yes I just think it's funny that the owner's manual states it has 50W output on VHF high power, and the alignment procedure says to adjust it to 48W. 

One of the most important parts of a communication system is the antenna. One of the locals who had a poor station including a crap antenna (basically because of poor construction) kept talking about wanting to get a 600W amp for SSB. Me and another person would always straighten him out by calling attention to his dipole antenna, which was not made very well. Put the money into a better antenna and you will get better results transmitting and receiving. Fortunately he never wasted money on the amp (probably couldn't afford it anyway). He never made his antenna better either (which he could afford to do).

[joeqsmith]

Similarly, both you & xrunner tend to take any contrary comments as personal affronts!
..
Most of my "circle" as far as one exists, is made up of old farts who are either still involved with Electronics in some form or the other, or retired from that field.

My guess is that is more your perception than anything.  After a career in broadcast, I would imagine within your inner circle of fellow hams you are still regarded high in the tech ranks.  On the internet, you have a much more diverse group.   

That said, if I had an SA, I would also probably not worry about a meter.

I am sure you wouldn't.  As I have stated many times on this forum, electronics is one of my hobbies.  I dare say that the majority of my efforts are purely for my own enjoyment.  Using the tools I have to make other tools is the norm. 

[bd139]

Yes I just think it's funny that the owner's manual states it has 50W output on VHF high power, and the alignment procedure says to adjust it to 48W. 

One of the most important parts of a communication system is the antenna. One of the locals who had a poor station including a crap antenna (basically because of poor construction) kept talking about wanting to get a 600W amp for SSB. Me and another person would always straighten him out by calling attention to his dipole antenna, which was not made very well. Put the money into a better antenna and you will get better results transmitting and receiving. Fortunately he never wasted money on the amp (probably couldn't afford it anyway). He never made his antenna better either (which he could afford to do).

That’s one thing that actually made me laugh a few months back. Was talking to someone who is rather well known on the QRP side of things. Does milliwatting on homebrew kit. Has a couple of near top ranking miles per watt things. What they never tell you on these boasts is the antenna which is never a bit of wet string as some hams like to persuade everyone they’re using when they’re really pushing 50W up the poot on a G5RV and lying about the power.

Of course he runs the entire thing with a 40m beam, rotator and coax about an inch thick. 50cm of coax weighs more than his transmitter but yeah you can reach Australia on a couple of 2n3904’s then  .

But yeah 5% extra power on your TX, meh.

[joeqsmith]

I let the DAS run overnight attached to the Fluke standard without a beach towel.  Closed the door to let the room build some heat.   Filter needs to be setup correctly.

[joeqsmith]

It may be a little faster than the Coaxial Dynamics product shown in the previous video.     

[xrunner]

You're going retro heh?

 

I'm calling the "Ham" power meter done (if anything's ever really done). Since there's still a lot of summer left and it's too hot to go outside and play, and I have another AD8310 board, I want to make another power meter. Not a Ham band power meter. SMA on the rear. I won't need all those warnings either.

OK one wouldn't hurt. 

I want to go from 1 to 450 MHz, anywhere in that range, and be within +/- 0.5 dB. I'm going to go back and look at the data I collected when I first got the AD8310, and I might take some more data as well. I'll still use cal factors but they won't be selected by a button but by another method. The cal factor will be calculated per frequency step (1, 5 10, 50 MHz don't know yet) based on what I can derive, but we'll see if it works. OK let's put it this way - it will work, but the question is: how accurately will it work?

Also watching what Joe and bd139 come up with.

[vk6zgo]

Yes I just think it's funny that the owner's manual states it has 50W output on VHF high power, and the alignment procedure says to adjust it to 48W. 

One of the most important parts of a communication system is the antenna. One of the locals who had a poor station including a crap antenna (basically because of poor construction) kept talking about wanting to get a 600W amp for SSB. Me and another person would always straighten him out by calling attention to his dipole antenna, which was not made very well. Put the money into a better antenna and you will get better results transmitting and receiving. Fortunately he never wasted money on the amp (probably couldn't afford it anyway). He never made his antenna better either (which he could afford to do).

That’s one thing that actually made me laugh a few months back. Was talking to someone who is rather well known on the QRP side of things. Does milliwatting on homebrew kit. Has a couple of near top ranking miles per watt things. What they never tell you on these boasts is the antenna which is never a bit of wet string as some hams like to persuade everyone they’re using when they’re really pushing 50W up the poot on a G5RV and lying about the power.

Of course he runs the entire thing with a 40m beam, rotator and coax about an inch thick. 50cm of coax weighs more than his transmitter but yeah you can reach Australia on a couple of 2n3904’s then  .

But yeah 5% extra power on your TX, meh.

The point with QRP is that you don't always need a spectacular antenna, etc, if the person on the other end does have such a setup.
One of the most prolific QRP enthusiasts in OZ is Peter Parker VK3YE, who often uses both low power & compromise antennas.
Of course his "spidey sense" may help!

I have no such pretensions---the most likely thing on HF for me is 100W to a low dipole, or sometimes 10W to a mobile antenna on the patio roof.
Like the guys on the Bonneville dry lakes "I run what I brung!"

[joeqsmith]

The two 8310's have been modified and mounted into the case.   

You're going retro heh?

For now, I just wanted to provide some idea on the update rate.   Next step, wait for the paint to dry.   

[xrunner]

Oh nice! This is going to be interesting. 

[joeqsmith]

I want to go from 1 to 450 MHz, anywhere in that range, and be within +/- 0.5 dB. I'm going to go back and look at the data I collected when I first got the AD8310, and I might take some more data as well. I'll still use cal factors but they won't be selected by a button but by another method.

I had thought about measuring the frequency and using a lookup table.  For my very low target frequency I didn't think I would gain anything.  The couplers are fairly flat.  For what you want to do, I almost think it would be required.