CB and Ham Radio Techs Love Their Bird Wattmeters

[fourfathom]

Like I said earlier, I know of no hams - none - that have made anything like that kit. In fact I can't say I know any at all that have made any sort of kit electronics.

[Creaky old-timer voice] Well, when I was a boy I soldered together my own Heathkit oscilloscope, and converted surplus WW2 radios for ham use by replacing the dynamotor with a 110VAC power supply, rewiring the hollow-state device (vacuum tube) filament strings, and pulling out variable capacitor plates to re-tune the VFO.  And my friends were doing the same and more. [/Creaky old-timer voice]

Admittedly, that Heathkit O-Scope was *much* simpler than the Elecraft rig above, and these days I can buy a much better scope for pennies (relatively).  But things have changed in the ham technology world, where there is no good reason (other than curiosity) for someone to build a "regular" radio or test equipment, so that pathway to technical competence is less enticing.  But there are still hams building kits -- look at QRP Labs, and others.

[bd139]

I've fixed 4 QCXs other hams built and built 3 to order, 1 of which was quickly destroyed. YMMV on that.

[fourfathom]

For your amusement, here are two boards from my buoy project: A controller board and a power amplifier.  The controller contains the GPS, SAMD processor, Si5351 clock chip, and power-control circuits.  It sends 10 MHz (+/-) digital to the "power" amplifier (1W Class-E).

It's been lots of fun getting these running. I'm quite pleased with my ISR and FIR DSP filters that apply a nice Bessel smoothing to the frequency-transitions (the FIR length varies with bit-rate and mode specs).  Watching the spurs drop as I worked on the filters was a nice way to see what I'd previously only known in theory.  The amplifier is 95+% efficient so those paralleled SOT-23 transistors stay quite cool.  In fact, the ferrite core on the feed choke gets warmer than the transistors (but just a couple of degrees, it's still cool to the touch.)

[xrunner]

The problem of was when there was no load applied,  the system did not read 0.0.  Being an engineer, I was telling my friend who cares.  It was something like 0.01% accurate.  You could see it bothered them so I think I had a Tare function which I think still wasn't good enough and I ended up coercing readings below some cutoff to zero.   The odd part is my friend wasn't some beginner.     

Where I work, I have seen similar problems, not related to electronics or mechanical measurements.

That's why I had one version of the software show "input below -73 dBm" because some people would wonder why it's not zero if there is no power at the input. But then I threw caution to the wind and didn't do it. 

For your amusement, here are two boards from my buoy project: A controller board and a power amplifier.  The controller contains the GPS, SAMD processor, Si5351 clock chip, and power-control circuits.  It sends 10 MHz (+/-) digital to the "power" amplifier (1W Class-E).

What exactly does the bouy project do? I know what a bouy is and that your transmitting a signal, but for what purpose? Are you wanting to track a bouy let go in the ocean? I tried searching on the forum under your name for "bouy" and it returned nothing ( but I suppose for this forum software that shouldn't be a great surprise ).

[fourfathom]

For your amusement, here are two boards from my buoy project: A controller board and a power amplifier.  The controller contains the GPS, SAMD processor, Si5351 clock chip, and power-control circuits.  It sends 10 MHz (+/-) digital to the "power" amplifier (1W Class-E).

What exactly does the bouy project do? I know what a bouy is and that your transmitting a signal, but for what purpose? Are you wanting to track a bouy let go in the ocean? I tried searching on the forum under your name for "bouy" and it returned nothing ( but I suppose for this forum software that shouldn't be a great surprise ).

The buoy does whatever strikes my fancy if I ever finish it.  I retired about 20 years ago, but still spend hours most days playing with electronics and related stuff.  I like solving problems.  I live on an island in the Salish Sea (between Vancouver Island and the Washington State mainland, and I occasionally sail to Hawaii and back, so designing a telemetry / beacon buoy sounded like a fun problem.

And it was!  It lead me along many paths and ratholes, led me to upgrade my tools, design new measurement gear, get my hands dirty with stuff I'd only known in theory.  I decided to include multiple communications modes within the 30 meter ham band (10.xxx MHz) so I got to lean the protocols (usually a combination of reviewing the source code, and the published specs).

At the moment the buoy will measure position via GPS, temperature, and some internal voltages.  I *may* add a 3-axis accelerometer, gyroscope, and magnetometer to try to measure seastate and wind, but that's a big problem that may drag on longer that I have patience for -- I have given myself permission to put down any project if I lose interest (one of the joys of it being a hobby rather than a job).

There are "rules" issues regarding telemetry on the HF ham bands, but if I call it a propagation study beacon, keep the power and the transmit duty-cycle low, and don't trespass in the more popular sections of the bands I figure I can avoid serious prison-time.  The whole buoy fits into a short section of 2" PVC pipe, with a very short (and inefficient, perhaps -20dB) antenna.  Two small 1W solar panels will provide plenty of power.

Here's a PDF presentation I gave to the local ham club that mentions the buoy: http://wb6cxc.com/?attachment_id=86
I also discuss it a bit in a presentation I gave at the 2021 MicroHAMS conference (I'm Paul Elliott, WB6CXC): https://www.mhdc.live/presentation-archive/2021-conference  Warning: I do go on and on...

[xrunner]

Insertion loss of Hirose HCS2-110-F NO and NC positions up to 1 GHz. 

DC - 4 GHz specified to be 0.2 dB Max. Pretty close. I won't be using them over 450 MHz.

[bd139]

Random one. Throw "zombie ham radio operator" into one of the DALL-E image generators... sure I saw this guy at a hamfest...

[xrunner]

No dude I've seen that guy at a local hamfest! 

Random one. Throw "zombie ham radio operator" into one of the DALL-E image generators... sure I saw this guy at a hamfest...

[mnementh]

Noticed the low SN has a catch diode.   Was it later added internally?

The datasheet doesn't indicate they have a diode internally. I think some of these were in a system wired in parallel. I will check for internal diode when I test them further.

If I were to sell these power meters, should I do it the Chinese way - meaning I wouldn't include any documentation or instructions? I was gaming out how I would respond to a customer and it would go down like this -

Buyer: "I connected the power meter to a 50 W ham mobile radio. It worked for about 2 seconds and now it doesn't even light up the display and it smells strange!"

Me: "Well first of all, did you read the instructions included with the unit?"

Buyer: " No! There were NO instructions included! I thought there was something amiss."

Me" "Well that's the problem right there. You admit not reading anything and you realized something was missing.

Buyer: "But why were they missing?"

Me: "Environmental waste reduction initiatives. If you already have this meter and just bought another one, you wouldn't need another set of instructions."

Buyer: "But I never had one before!"

Me: "You should have contacted me to get the instructions then. I can't be responsible for you not understanding how it operates if you didn't even want to go to the trouble to get documentation. I'm under strict controls to reduce paper waste. The documentation also includes a red warning label to be installed by the RF input so you will be advised not to go over the power limit."

Buyer: "Warning? Red label? What warning!"

Me: "However, since you reached out I will be happy to send you the instructions and warning label so you will understand where you went wrong - at no charge to you! Also a sneek preview of new upcoming products."

Buyer: "    "

I've heard this spiel somewhere before... where was it...



https://www.eviscerati.org/comics/hd/1997/08/smoke-mirrors-and-behind-green-curtain/

Oh, yeaaaaah.

mnem
why are you reading this?

[mnementh]

   The second version of "Power Meter" (I know catchy name eh?) is completed...

That's actually looking pretty awesome, but I thought I'd pass on something I learned through trial & error:



Build-Tak print surface is just the nuts for making faceplates and other stuff that is going to be visible. It's what makes the nice nubbly "sandstone" finish on this hp medallion; it was printed face-down with a slight increase in temp and feed rate/extrusion to make the print lines disappear into the texture. The "windowscreen" appearance of the backfill is just my "bridging mode" settings.

I have a sheet of Build-tak on one of my older printers, and on one of the removable glass printing surfaces on my daily driver CR-6SE.

Cheers!

mnem
*toddles off to ded*

[A.Z.]

Like I said earlier, I know of no hams - none - that have made anything like that kit. In fact I can't say I know any at all that have made any sort of kit electronics.

[Creaky old-timer voice] Well, when I was a boy I soldered together my own Heathkit oscilloscope, and converted surplus WW2 radios for ham use by replacing the dynamotor with a 110VAC power supply, rewiring the hollow-state device (vacuum tube) filament strings, and pulling out variable capacitor plates to re-tune the VFO.  And my friends were doing the same and more. [/Creaky old-timer voice]

Admittedly, that Heathkit O-Scope was *much* simpler than the Elecraft rig above, and these days I can buy a much better scope for pennies (relatively).  But things have changed in the ham technology world, where there is no good reason (other than curiosity) for someone to build a "regular" radio or test equipment, so that pathway to technical competence is less enticing.  But there are still hams building kits -- look at QRP Labs, and others.

you are right; just to bring an example... VNAs are nice, but ... how many "modern hams" own a GDO or know the many ways of using it (sex stuff not included, I'm referring to regular use, by the way)

--
Andrew

[bd139]

“modern” ham here. I know how to use a GDO. I also owned more than one 

[xrunner]

“modern” ham here. I know how to use a GDO. I also owned more than one 

[mnementh]

I've owned a couple... never did learn how to use 'em tho.

mnem
Maybe I needed better alligators to stay hooked on my    ...?   

[fourfathom]

Front panels are always a challenge -- those look good.  You might consider using soldermask color options.  Here is a faceplate of mine, done by JLCPCB using blue soldermask and their regular silkscreen.  I used black marker on the PCB edges, but have since used a blue Sharpie permanent marker and it looks better.  These PCBs are ridiculously cheap, and are double-sided copper with plated-through connector holes.

[Intermod]

Isn't that the point of a Bird 53? The elements are so tuned that by filtering out harmonic products, their appearances are greatly reduced.

[mnementh]

Had no idea they had already commoditised the idea. Might have a look at one of them as well for comparison.

Have been doing some thinking about extending the dynamic range of these power meters as a side note. I want to see if I can stick another 40dB on the front end of an AD8307. There is a solution involving an AD603 but due to the noise bandwidth that's only usable in a 200KHz span. This went down the line of thinking about adding a mixer and LO to the front end and sweeping for peak power. Then I realised I invented a spectrum analyser again. And then I realised I should probably just finish that project 

Here's another to add to the "Chinesium Commodity Doo-dad RF Meter" mix:

   

https://www.ebay.com/itm/384348942837

https://www.ebay.com/itm/384370100222

mnem
 

[bd139]

Almost worth it for the enclosure 

[mnementh]

Yeah, seller appears to have a lot of such Chinesium doodads; evidently it's all he does. A regular Banggood-type storefront:

https://www.ebay.com/sch/i.html?_ssn=pincei_de&store_name=pinceishop

Here's a 40dB 5-6Ghz PA in the same enclosure for $23 shipped: https://www.ebay.com/itm/384006165446

mnem
 

[joeqsmith]

you are right; just to bring an example... VNAs are nice, but ... how many "modern hams" own a GDO or know the many ways of using it (sex stuff not included, I'm referring to regular use, by the way)
--
Andrew

Do I dare ask.... 

About 43 minutes in, you can see my old James Millen grid dip meter in use.

[bd139]

Diversion back into watt meters. Technical post for a change. Snagged a Farnell TM6 RF voltmeter last weekend at a radio rally. Obviously it's been broken by a ham and bits are rotten as they have been stuck in a wet shed for 20 years (ffs seriously hams!). For £15 I'm happy even if it turned out to be a meter in a box for the money. It's a learning exercise fixing it. This is a relatively ancient bit of kit (1970s) which gives an indication from -50dBm to +20dBm up to 1.5GHz which is a surprisingly large amount of dynamic range and frequency. It's based on a fairly simple dual diode detector that you hook on the back of a 50 ohm inline termination.



So implementation-wise the thing uses a dual diode peak detector to pick off the positive and negative peaks and then shoves them in a chopper to generate a neat square wave, the amplitude of which is dependent on the detected voltage. Kills any DC offset of a single amp then. This is then amplified with a variable gain AC amplifier (range selection) a couple of times so the offset is fractional after which it's integrated and a fired at a meter. Some of the lower power ranges have some diode curve compensation built in as well which is going to be a bitch to trim up. It'll keep me off the floozies for a bit.

Simulation of front end as the manual is crap:



Interested to see how it compares with an AD8307 after I've fixed it. With a 40dB power tap and my now working Marconi 2022E I reckon it's quite a useful bit of kit.

Low tech innards:



Lame ass detector head:

[xrunner]

Front panels are always a challenge -- those look good.  You might consider using soldermask color options.  Here is a faceplate of mine, done by JLCPCB using blue soldermask and their regular silkscreen.  I used black marker on the PCB edges, but have since used a blue Sharpie permanent marker and it looks better.  These PCBs are ridiculously cheap, and are double-sided copper with plated-through connector holes.

It looks fine but I have a 3D printer and I'm going to use that to make as much as I can. I guess this is a rant but I'm tired of so much coming from China. Geez it's ridiculous to me that we can't even get something like that made here in the states. 

Diversion back into watt meters. Technical post for a change. Snagged a Farnell TM6 RF voltmeter last weekend at a radio rally. Obviously it's been broken by a ham and bits are rotten as they have been stuck in a wet shed for 20 years (ffs seriously hams!). For £15 I'm happy even if it turned out to be a meter in a box for the money. It's a learning exercise fixing it. This is a relatively ancient bit of kit (1970s) which gives an indication from -50dBm to +20dBm up to 1.5GHz which is a surprisingly large amount of dynamic range and frequency. It's based on a fairly simple dual diode detector that you hook on the back of a 50 ohm inline termination.

Yea let's get back to power meters. That's pretty old school for sure. Nice copper PCB though. I have a Tektronix RF probe hanging in the closet, but I never use it anymore. I also have a Boonton Model 42A power meter that I need to get a parts mule for but I can't find one of them cheap enough. Remember I talked about it in the TEA thread a while back. A local ham picked it up at a local hamfest and didn't understand how to use it so he was going to do some weird project with it. Fortunately I saved the poor thing from mutilation. Had a good sensor though which I'm surprised he didn't ruin because he said he transmitted with a HT 5W to test the meter. Luckily I don't think he even did that right. 

What I'm going to work on for no other reason than I want to see how far I can take it, is a self-contained power meter this time that can go from say -70 to +40 dBm. That way you could check out a QRP rig or handie talkie up to 10 W. That's what the SMA switches are for, so you can switch in an attenuator for the higher powers. I don't think it could be made to switch automatically fast enough (too much time and would burn out the log amp) so it will be manual switching.

The issue will be finding the right attenuator first of all - I want 40 dB and at least 10W and be the smallest one I can find. a 40 dB att. will shove the power from a 10W rig back to 0 dBm and that will be OK for the log amp. If I can get it in the case I want I'll have a fan  that automatically comes on at a certain temp so you don't have to worry about the fan running all the time for no good reason. We'll see what happens at least it keeps me busy and out of the bars ...

 

[joeqsmith]

Diversion back into watt meters.

Yea let's get back to power meters.

I've seen people post about using the NanoVNA for a Wattmeter.   Maybe that's why some of the hams plugged them directly into their radios. 

Self contained makes sense.  Maybe burn off some of the RF power to run the electronics.  Why waste it....  ...... ..... 

Nice looking old meter.   So that squarish looking brown thing is a 1k?  I don't think I have ever seen a resistor packaged like that.   

[Tony_G]

... Snagged a Farnell TM6 RF voltmeter last weekend at a radio rally.

Nice - That seems to be a way more accessible type of meter than the 8405A/8508A meter series from HP - I've always found it surprising how quickly things can go pear shaped if gear isn't stored properly.

TonyG

[xrunner]

I'm working with a 3D printer upgrade for a while (I know - why inflict pain on myself    ) but I did find an attenuator that might work for this project. SMA 40 dB 10W small footpint.

What do you guys think of this -

Small 40 dB 10W attenuator