CB and Ham Radio Techs Love Their Bird Wattmeters

[joeqsmith]

My personal technique to repair RF connectors.   

[xrunner]

LOL good video Joe. 

Found another example of superior quality control. One of the top covers they missed countersinking three screw holes (1st pic).

 

I'm going to use the boards that came with the metal cases now for this project. I changed the input components as has previously been explained in this thread.

Each AD8307 chip can have a slightly different response, the most important is as follows:

log slope 25 (+/- 2) mV / dB

log intercept is -84 (+7 / -3) dBm

So at a minimum I'll have to re-cal but I think I'll more accurately determine these values for each board. I was using the "typical" values from the datasheet in the software: 25 mV / dB and log intercept of -84 dBm.

I labeled the boards "A" and "B" (I know pure genius). Using my Agilent 8648A I made a series of measurements and found the responses of the boards as follows:

Board "A" has a response of 24 mV / dB and a log intercept of -84 dBm
Board "B" has a response of 25 mV / dB and a log intercept of -82.4 dBm

That's all in-spec, but now I know the actual measured values, to be used in the power calculations.

My collection of parts at the moment shown, except the case. I called Amazon today and he said they put my order in the wrong bin and it returned to some Amazon warehouse. Supposed to be sent out again -

"don't worry".

[metrologist]

My personal technique to repair RF connectors.   

Almost perfect. 

[joeqsmith]

One of the top covers they missed countersinking three screw holes (1st pic).

Not sure why their quality is so poor.   I assume yours was poorly aligned as well. 

I took some time today to sketch out the front end of that junk NISSEI Watt meter I reviewed and put it on the network analyzer to see if I could sort out the problem.  Talk about poor quality.   

[xrunner]

I don't understand why they try to hide the adjustments on these low-end things. Hams buy them and they're supposed to know, or try to learn, how to do these types of adjustments if they want to. Why not make a label that doesn't hide the screws? Why not say which adjustments do what in the instructions? It's just irritating. What do they think - NASA is going to calibrate a satellite system with it? 

Today, this is the message from Amazon for my delivery:

Undeliverable

Unfortunately, a problem occurred with your shipment and we no longer expect it to be delivered. We’re sorry for the inconvenience. If you have not received your refund within 5 days, please contact us.

Lookin' like this project is gonna to take a while ... 

[joeqsmith]

I don't understand why they try to hide the adjustments on these low-end things. Hams buy them and they're supposed to know, or try to learn, how to do these types of adjustments if they want to. Why not make a label that doesn't hide the screws? Why not say which adjustments do what in the instructions? It's just irritating. What do they think - NASA is going to calibrate a satellite system with it? 

You still think ham radio is about enhancing the art.  lol.  For the 1%ers, I agree.  Then again, it is pretty obvious.  Having a label with access to the screws would have been nice.  Flip side, there are some that would mess it up then claim a warranty.  The label acts as a deterrent?     

[joeqsmith]

Google images located the RS-70 internal view.  I have no idea if this one works or where the photo came from but it appears the braid was left floating.   

[xrunner]

You still think ham radio is about enhancing the art.  lol. 

Everyone has fantasies on occasion. 

[xrunner]

Still waiting on my case from Amazon. I had to re-order it as they simply said the previous order was "undeliverable" and are issuing me a refund. What a mess.

In the meantime, I removed the AD8307 boards I was using and I'm wiring in the new ones that reside in the metal enclosures. The boards I was using had both an SMA and solder pads for the output DC level. I was using the solder pads. But now I'll use the SMA outputs on these enclosed boards. So I just scavenged two cables to use for that.

I said previously I went to the trouble of measuring the actual log intercept and mV / dB slope response for each of these two boards. I will now modify the software to use these separate values for each channel - FWD and REV power.

[joeqsmith]

Did you get the holes counter sunk and the connector replaced?  Or did you used the pliers/drill blanks?

[xrunner]

Did you get the holes counter sunk and the connector replaced?  Or did you used the pliers/drill blanks?

Not yet. I can move the dented SMA to the opposite side (DC  level out) very easily so it won't be an issue there. I will touch the three holes with a drill to provide a countersink. I may receive my cases by Friday. Then I can begin to see how to package this project in the available space.

I did receive a message from the seller of the shielded units, and I sent a message back with two pics to support my claims. Lets see what transpires.

 

You have received a message from the Amazon Seller - Geeriu

AD8307 RF Power Meter, Keenso AD8307 RF Power Meter Logarithmic Testing Detector 0.1600M 75~15dBm Module with Case

Dear customer nice day thank you for your purchase have you received the item bought from my store? does this item meet your expectation? please contact us if the item has problem we will try our best to solve the problem for you wait for your reply best regards

I got the items but one of them had a dent on the SMA connector. Also three of the screw holes were not countersunk. Poor quality control!

[joeqsmith]

If they decide to send you a replacement, show him my photo and video as well.  Maybe you can use that to get a second replacement as well.  Tell them I said you could have it.   

Amp does make a part that will replace it but you may spend more than the whole amplifier.   You may be able to get a bag of replacements from China as well.   

[xrunner]

Response and counter-response. At least I got "best wishes".

dear customer,
sorry for the inconvenience,
regarding the problem,
you can contact amazon for replacement.
or you can return the item to Amazon and get your full refund,
any other problem, please contact us.
best wishes

You asked me if I had any problems -

"please contact us if the  item has problem
we will try our best to solve the problem for you"

and to contact you if I did. Well these are the problems I'm writing you about. I would think you would send me perhaps a replacement SMA connector or top plate so I can replace the parts, but you say to contact Amazon. You then say "any other problem, please contact us".

Why are you asking me to contact you with my problem if you can't solve it? What sort of problems do you actually solve?

[joeqsmith]

I doubt most of these exporters specialize in anything but finding cheapest and shipping.  In this case, guessing they get the rejects and peddle them off.  Plenty of hams with drill blanks out there ready to work their magic.

I assume no warranty on anything I get from China. 

[xrunner]

Oh I know what's going on. They automatically sent out boilerplate message saying if I needed any help to contact them. But I don't think they actually expected a response. All they do is tell you to contact Amazon so why send the message at all. And every message you get "Best Wishes" or "Best Regards".

Here's the last response from them:

Dear customer ,
Feel so sorry for the trouble.
as this one is fulfilled by amazon, it is shipped and handled by amazon directly,
if you have any problems when you "contact amazon customer service",
sellers cannot arrange replacement.
best wishes

And me:

You actually don't provide any help at all. So why did you even send me a message offering help to begin with? Enjoy the review I'm writing for this product.

Best Wishes

[joeqsmith]

Post a link or post the review here once you have it up so we can all have a bit of entertainment.   

[xrunner]

Post a link or post the review here once you have it up so we can all have a bit of entertainment.

There's really not much to it. I just complained about the dented SMA and the holes that didn't get countersunk. I gave two stars. Neither the seller (nor anyone else) can reply to your individual review, if they did it would be a sh*t show.

Here's what I got back from my last message:

dear customer
nice day
thank you for your email
but so sorry we are having our day off now
we will try our best to solve your problem when we work
so sorry for the trouble
best regards

Another "best regards" to brighten my day.

I tested the current project with the new shielded log amps. It works OK but needs new cal data per band - that can come later. I'm taking the project apart because I'll have to start playing Tetris with the pieces, to see how I can package them into a usable piece of gear. Should have the case by tomorrow then we can take a look at the possibilities. For now -

dear forum members
nice day
thank you for your attention
but so sorry we are having our evening off now
I will try my best to provide more content when I return
so sorry for the trouble
best regards,

xrunner

 

[xrunner]

I received the case. It's looking like there will be two levels to the interior. Maybe RF stuff on the bottom and computing on the top. So with the controller on top and wires being plugged in, it's going to be a tight fit and I expect I'll have to extend the case height (sides) with some 3D printing tricks.

All cases I found were either a little too small, or way too large. For example, if the case was too small in height, picking the next bigger one the seller had, so I got the height I needed, made the other two dimensions proportionally bigger as well. I also found cases that were OK in height but not width - same thing happened as you go to the next size.

So I settled on one I could make larger in height by way of 3D printing vertical side extensions. The interior sides have channels that will enable me to do this. Remember, the original front and back pieces will not even be used. So the 3D printed ones with the openings I need, will be made to accommodate the new height easily.

But in a way I think it will kind of look neat if I pick the right color.  BTW the feet it came with are plastic not rubber. Like attaching four round ice cubes to the bottom.

[joeqsmith]

Battery powered?

[xrunner]

Naw, no batteries, just external 9 to 12 VDC.

Playing around with the parts placement on the bottom with a cardboard cutout envisioning a 3D printed mounting plate. Rather than have it completely sit atop the pre-made mounting holes in the case bottom, it will sit flat on the bottom and the raised holes will fit through open holes, such that a self-tapping screw and washer can be used to hold the plate down. Because there will be yet another plate on top of this one with the Due controller, this will make the final case height a little less tall.

The mounting slots on the sides of the coupler are for M4 hardware, and the threaded holes on the bottom of the AD8307 cases are M3. The AD8307 shielded cases will be held in place by M3 hardware coming up from the bottom of the plate (through a recessed hole). The coupler will be held by four screws from the top. But what will they screw into?

Last year I ordered a complete set of threaded brass inserts. I also got a set of tips that you put in a Hakko soldering iron to heat-set the inserts into a hole in a 3D printed part. I learned how to do this in some experimenting sessions, but I have not used them in a project. Now is the time.

I can start working on this design in Fusion 360. But as I have said, I don't want to run the 3D printer yet because it's just too hot around here and I don't want the hours of extra electricity usage at this time. In about two weeks the long term calendar claims the temps will be back in the 90s, then we will see ...

[joeqsmith]

Getting closer.

Seeing the attenuator on your setup, I wonder if the Nissi Watt meter is purposely not symmetrical as well to make the reflected measurement more sensitive.  I have not done anything with it yet.

The one I made was symmetrical so the only difference between the two ports is how the software treats them. 

[xrunner]

Made some progress on the design of the bottom mounting plate. The holes are correct. It doesn't need to cover the entire bottom though. So I'm going to remove material where it's really not needed from some of the edges and also cutout areas inside. I'll place circles where I want the mounting holes for the coupler and log amps, then I'll easily see where I can remove material from the design.

I need to review some videos regarding the brass inserts. I'll probably make a few small test parts so I can get the right size hole for the insert before I commit to printing the whole part. If the brass insert doesn't fit properly when heated and pushed into the plastic, I'd waste the 3D print for nothing.

I have a good starting point anyway.

[xrunner]

Still working on my CAD designs for this project - took a break to check the Bird listings on Ebay. There's a few of these Bird AT-800 Handheld Wireless Antenna Tester / Analyzers on Ebay:

eBay auction: #235093497882

Most are for parts or not working, around $15 to $35. Maybe someone transmitted into them and toasted the inputs? Outside the commercial sector, would only be good for the 33 cm ham band 902 to 928 MHz, which is largely unused by hams. Good luck selling that electronic waste.

I like the note on the PCB in this pile of junk - it sure looks like it says "I Don't Know".

 

I'm sure you don't. 

[xrunner]

A little more progress on the bottom mounting plate. Got all the holes accurately placed for mounting the coupler and the two AD8307 cases. The screws for these two smaller cases come up from the bottom. The four holes for the coupler will have heat set inserts for M4 screws. I still need to remove areas by cutting out unnecessary material.

[xrunner]

I did some work creating the riser panel needed for each side of the case. I also cut out places in the bottom plate to remove unneeded material and save time printing.