Test Equipment Anonymous (TEA) group therapy thread

[bd139]

400khz-24Mhz and 120-160Mhz at the moment.

AWG is good to 25MHz which is fine for my requirements at IF stage anyway. I can do bode plots. I’ve got both set up on LXI with a python script. I’m using an Si5351 module and power detector with return loss bridge for VHF but it’s a dick. I could turn the whole thing into an SNA but I just can’t be arsed with it to be honest. I want to solve a problem here for once rather than build a tool then by the time I’ve done that, forget what the problem was

[tautech]

Have you seen Dave's vid doing Bode plots with a DSO and just in sweep mode with an AWG ?
Worth a look.
https://www.eevblog.com/2012/12/08/eevblog-396-bode-plotting-on-your-osciloscope/

[mnementh]

I'm probably going to show my ignorance of modern Amateur Radio here, but I've been into FPV Model Aviation for a while now, and the technology being developed by amateur designers for this aspect of the hobby is nothing short of amazing. We're talking analog video and audio at 480P-720P res over a couple kliks range on 5.8Ghz using CPW antennas smaller than a golf ball at less than 2m elevation. And complete RX/TX setups with diversity in some cases for less than $50.

Now it's true that most of this tech is evolving in the 5.8GHz band, but some goes down to 2.4 and even 900MHz, and the receivers... jeez, auto tune with spectrum analyzer on an OLED screen; it's like they threw in a 6GHz RF Explorer as an afterthought on a $75 receiver. And now they have versions that use any Android phone capable of Host mode (with or without OTG/External charging) as a display for $25. Just CRAZY.

 

Long gone are the bad old days like the Flying Pumpkin here...

Anyways... my point being... it seems to me that this tech should be adaptable to other amateur radio applications and bands by folks who REALLY know something about it.


This is one of the guys who pioneered this tech:

https://www.laforgefpv.com/vrx-pro

http://team-blacksheep.com/shop/cat:fpv_5g8vrx#product_listing

Here are the cheapo clones:

https://www.banggood.com/Eachine-ROTG02-UVC-OTG-5_8G-150CH-Dual-Antenna-Audio-FPV-Receiver-for-Android-Tablet-Smartphone-p-1242422.html

https://www.banggood.com/Eachine-PRO58-RX-Diversity-40CH-5_8G-OLED-SCAN-FPV-ReceiverProtective-Case-for-FatShark-Goggle-p-1180980.html

https://www.banggood.com/Eachine-R051-150CH-5_8G-FPV-AV-Recevier-Build-in-Bat-For-iPhone-Android-IOS-Smartphone-Mobile-Tablet-p-1196214.html

https://www.banggood.com/Eachine-PRO58-RX-Diversity-40CH-5_8G-OLED-SCAN-VRX-FPV-Receiver-for-FatShark-Goggles-p-1160357.html

[bd139]

RF Explorer starts just as my interest in HF stops unfortunately. Fine for much higher frequencies in VHF and UHF however.

Have you seen Dave's vid doing Bode plots with a DSO and just in sweep mode with an AWG ?
Worth a look.
https://www.eevblog.com/2012/12/08/eevblog-396-bode-plotting-on-your-osciloscope/

Yeah I can do that as well. I’ve got marker generator output. Problem is that it’s difficult doing analysis. For example how do you find the 3dB point? If you’ve got an SA with TG you can run a marker across easily. Calculating Q of a crystal filter for example is hell. This is why I wrote automation for it. Technically as I can use two probes and measure phase with this I can use it as a VNA up to 25MHz fine. Just haven’t bothered yet.

It’s mostly software. Apart from above HF. At that point you need hardware unfortunately.

[tautech]

Have you seen Dave's vid doing Bode plots with a DSO and just in sweep mode with an AWG ?
Worth a look.
https://www.eevblog.com/2012/12/08/eevblog-396-bode-plotting-on-your-osciloscope/

Yeah I can do that as well. I’ve got marker generator output. Problem is that it’s difficult doing analysis. For example how do you find the 3dB point? If you’ve got an SA with TG you can run a marker across easily.

With a smart setup you can just use the DSO cursors and find the roll off.

[BillB]

I’m currently slaving at the school summer fete today so tomorrow I’m staying at home and being an unsociable bastard. By that time I will have had more than enough of the human race.

I'm an unsociable bastard everyday and it is so refreshing. 

Unsociable Bastards Unite!


or maybe not.

[Specmaster]

I’m currently slaving at the school summer fete today so tomorrow I’m staying at home and being an unsociable bastard. By that time I will have had more than enough of the human race.

I'm an unsociable bastard everyday and it is so refreshing. 

Unsociable Bastards Unite!


or maybe not.

Aren't we all, shut away in our own little world of test gear in our labs which are often in their own rooms, certainly my family think I'm an unsociable bastard because elect to be here in my lab rather then with them watching the effing gogglebox. 

[bd139]

Have you seen Dave's vid doing Bode plots with a DSO and just in sweep mode with an AWG ?
Worth a look.
https://www.eevblog.com/2012/12/08/eevblog-396-bode-plotting-on-your-osciloscope/

Yeah I can do that as well. I’ve got marker generator output. Problem is that it’s difficult doing analysis. For example how do you find the 3dB point? If you’ve got an SA with TG you can run a marker across easily.

With a smart setup you can just use the DSO cursors and find the roll off.

Or just run ./3dB.py 1e3 110e6

[bd139]

I’m currently slaving at the school summer fete today so tomorrow I’m staying at home and being an unsociable bastard. By that time I will have had more than enough of the human race.

I'm an unsociable bastard everyday and it is so refreshing. 

Unsociable Bastards Unite!


or maybe not.

Aren't we all, shut away in our own little world of test gear in our labs which are often in their own rooms, certainly my family think I'm an unsociable bastard because elect to here in my lab rather then with them watching the effing gogglebox.

Television is a time hunter trying to eat us alive for nothing.

I watch the odd film and that’s about it.

[Mr. Scram]

I can’t stand grocery shopping. Get it delivered now! It annoys me that no one reverses into the parking spaces which means it turns into a pinball machine full of blind idiots. I’m hoping this software venture pays off. I’m done then. Going to hide somewhere and develop a super villain lair with laser sharks and a helicopter landing pad (no helicopter - can’t afford one!)

On the subject of TEA I’m sure this is the sun but I’m staring at the cheap end Rigol SA’s with TG and thinking I can just pop it on the credit card and put getting a new car off for another year. I hate buying cars anyway. Hmm. I suspect that’s “murder money” from SWMBO.

I'm starting to have second and third thoughts about having things delivered. In theory it's more convenient but considering I have to chase at least every other package for days, just going to a shop and stepping back out with what I need at that actual moment sounds quite appealing.

I'm fairly done with getting taken for a fool with all the postal service shenanigans. False information, ring and run, magic visits that never happened, you name it.

[bd139]

To be honest it’s pretty good here. Apart from parcel force who can never find me on the first delivery attempt.

[Specmaster]

Just fdor for shit and giggles I connected my voltage reference AD584-M up to my newest meters for comparison side by side, the BM867s is new, Fluke 8840A still has its calibration seal in place (date of calibration unknown) and HP 3478A had its CAL data lost during a recent battery replacement and was sent to RS for a full calibration which they returned saying that they could not get it to calibrate. I set about doing it myself armed with a copy of the service manual and an inexpensive voltage reference, current reference and some known resistors.

I set the meters running and let them warm up for the required time and a bit for good measure them connected them all to the voltage reference, the following photos show the results, I'm very pleased with the results.

[Specmaster]

Same here, postman, Hermes, DPD, ParcelForce and TNT all find me with ease and I can't remember the last time I had a parcel where I had to chase it about or collect it TBH.

[Mr. Scram]

It was quite alright before. I knew the delivery guy and he took a few seconds more to ensure that I really wasn't home. Now it's someone else and it's all over the shop again.

Other parties don't deliver as much, but those are hit and miss too. If I'm lucky I get to pick up my stuff a  day later a mile or so from here. I wish I was embellishing.

[bd139]

Just fdor shit and giggles I connected my voltage reference AD584-M up to my newest meters for comparison side by side, the BM867s is new, Fluke 8840A still has its calibration seal in place (date of calibration unknown) and HP 3478A had its CAL data lost during a recent battery replacement and was sent to RS for a full calibration which they returned saying that they could not get it to calibrate. I set about doing it myself armed with a copy of the service manual and an inexpensive voltage reference, current reference and some known resistors.

I set the meters running and let them warm up for the required time and a bit for good measure them connected them all to the voltage reference, the following photos show the results, I'm very pleased with the results.

Looking good 

[Kosmic]

Just fdor for shit and giggles I connected my voltage reference AD584-M up to my newest meters for comparison side by side, the BM867s is new, Fluke 8840A still has its calibration seal in place (date of calibration unknown) and HP 3478A had its CAL data lost during a recent battery replacement and was sent to RS for a full calibration which they returned saying that they could not get it to calibrate. I set about doing it myself armed with a copy of the service manual and an inexpensive voltage reference, current reference and some known resistors.

I set the meters running and let them warm up for the required time and a bit for good measure them connected them all to the voltage reference, the following photos show the results, I'm very pleased with the results.

Nice collection of DMM 

Your ad584 is pretty close to the expected values (mine is all over the place). 2.5v is spot on!

[tggzzz]

I can’t stand grocery shopping.

I love it; cooking is another form of geek construction. There is even a rather good book "Cooking for Geeks: Real Science, Great Cooks, and Good Food".

And, if you restrict yourself to the "for quick sale" items, it is like being at a hamfest Plus that reduces the choices you have to make and encourages you to buy things you might not think of.

[med6753]

I can’t stand grocery shopping.

I love it; cooking is another form of geek construction. There is even a rather good book "Cooking for Geeks: Real Science, Great Cooks, and Good Food".

And, if you restrict yourself to the "for quick sale" items, it is like being at a hamfest Plus that reduces the choices you have to make and encourages you to buy things you might not think of.

I'm ambivalent about it. I cook because I have to not because I particularity like it. And I'm diabetic so it has to be low carb/low sugar and stay away from processed foods. So that limits variety/selection. I do tend to buy the same things every week so it does make the shopping quick and easy...until I get to the checkout and wait for the little old ladies who insist upon digging through their purse to pay in exact change.     

[bitseeker]

Oh, FFS.  Here, have some .pdf

Thanks, mnem. Yeah,  moment. Sorry, Spec, brain was elsewhere.

[bitseeker]

A now for something a little different. The glowy thing I mentioned earlier arrived. It was packed really nicely and even had its cover.



Tada, it's a TI 4000 calculator with, count 'em, 12 Panaplex digits. Woo!



The listing said it was working, but, alas, a few keys don't. However, it was cheap so I think I'll keep it. The display alone is probably worth it.

The keyboard is a sealed unit that, according to the Old Calculator Museum, uses conductive pads to register key presses. So, that'll be interesting to investigate if the problem lies in the keyboard.



On the bottom side of the motherboard, it appears someone has been here before. There's flux in various places, including on one of the large DIP ICs as well as all the pins of the keyboard module. I guess this machine got lots of use.



The annoying thing is that several places have what appears to be blobs of clear epoxy (and less-than-stellar soldering). What's a safe way to get the epoxy off? It looks like the solder mask isn't all that durable.



Anyway, I think I'll save this one for when I have more time. It looks like it's going to take a fair bit of poking around and delicate surgery.

[mnementh]

I can’t stand grocery shopping.

I love it; cooking is another form of geek construction. There is even a rather good book "Cooking for Geeks: Real Science, Great Cooks, and Good Food".

And, if you restrict yourself to the "for quick sale" items, it is like being at a hamfest Plus that reduces the choices you have to make and encourages you to buy things you might not think of.

Whenever I do that, I come home with a stack of $3 apple and cherry pies from the "reduced for quick-sale" bakery rack. And because they're so close to over-due, I just HAVE to freshen them up in the convection oven (325 degrees/convection bake/30-40 minutes works MAGIC on a RFQS pie) and eat them up RIGHT AWAY... 

Oh, FFS.  Here, have some .pdf

Thanks, mnem. Yeah,  moment. Sorry, Spec, brain was elsewhere.

No problem. Part of being a geek; you forget sometimes that what's second-nature to you is not necessarily easy for others, even other geeks. 

And now for something a little different. The glowy thing I mentioned earlier arrived. It was packed really nicely and even had its cover.



Tada, it's a TI 4000 calculator with, count 'em, 12 Panaplex digits. Woo!

The listing said it was working, but, alas, a few keys don't. However, it was cheap so I think I'll keep it. The display alone is probably worth it.

The keyboard is a sealed unit that, according to the Old Calculator Museum, uses conductive pads to register key presses. So, that'll be interesting to investigate if the problem lies in the keyboard.

On the bottom side of the motherboard, it appears someone has been here before. There's flux in various places, including on one of the large DIP ICs as well as all the pins of the keyboard module. I guess this machine got lots of use.

The annoying thing is that several places have what appears to be blobs of clear epoxy (and less-than-stellar soldering). What's a safe way to get the epoxy off? It looks like the solder mask isn't all that durable.

Anyway, I think I'll save this one for when I have more time. It looks like it's going to take a fair bit of poking around and delicate surgery.

That's a gorgeous example of the breed; I used to have a similar Burroughs machine with the orange Panaplex display. I love the comma/decimals; these were an elegant weapon from a more civilized age.

I miss my TI-1025, with the "Great international Math on Keys" book... the faint inverter whine it made all the time it was on was oddly comforting, as was the little glowing red filament through the fluorescent display... and I learned more real math concepts & principles with that book & 4-banger than all my grade & high-school courses put together. Did I mention I'm congenitally math-defective? 



IIRC, these use rubber pad on the bottom of the hard keys that presses on a membrane keypad made of a matrix of criss-crossed silver-deposit flexible PCB made of mylar like the one shown above only with no overlay sheet. The layers are often glued together, which does make servicing the keypad pretty hard, but not impossible.

A little fresh solder & flux will take that epoxy right off your solder pads; then solder-sucker the whole mess away.


mnem
plerp!

[GregDunn]

Coincidentally, I just had the "epoxy on circuit board" problem a few weeks ago.  What worked for me was to get a fairly high powered soldering gun with a cheap spade tip; touching the epoxy caused it to just crumble away.  Be careful because of course the circuit board, if epoxy, will also disintegrate.  It may take a few tries to find the best temperature and "touch".

[bitseeker]

Tada, it's a TI 4000 calculator with, count 'em, 12 Panaplex digits. Woo!

...

The annoying thing is that several places have what appears to be blobs of clear epoxy (and less-than-stellar soldering). What's a safe way to get the epoxy off? It looks like the solder mask isn't all that durable.

That's a gorgeous example of the breed; I used to have a similar Burroughs machine with the orange Panaplex display. I love the comma/decimals; these were an elegant weapon from a more civilized age.

Thanks. I got this as a way to fill a gap in the display technologies in my lab. I didn't yet have anything with a Panaplex display. I considered a frequency counter or multimeter, but have lots of them already. Then, I thought of perhaps a clock, but the ones I've seen tend to go for a pretty penny and longevity wasn't going to be as good on an always-on device. Thus, I arrived at this.

I miss my TI-1025, with the "Great international Math on Keys" book... the faint inverter whine it made all the time it was on was oddly comforting, as was the little glowing red filament through the fluorescent display... and I learned more real math concepts & principles with that book & 4-banger than all my grade & high-school courses put together. Did I mention I'm congenitally math-defective? 

That's a neat little calculator. VFD. I saw on the Datamath site that TI even made one model of handheld with Panaplex.

IIRC, these use rubber pad on the bottom of the hard keys that presses on a membrane keypad made of a matrix of criss-crossed silver-deposit flexible PCB made of mylar like the one shown above only with no overlay sheet. The layers are often glued together, which does make servicing the keypad pretty hard, but not impossible.

A little fresh solder & flux will take that epoxy right off your solder pads; then solder-sucker the whole mess away.

Thanks for the info and epoxy elimination tip. I wasn't sure what would be safe for the PCB.

Coincidentally, I just had the "epoxy on circuit board" problem a few weeks ago.  What worked for me was to get a fairly high powered soldering gun with a cheap spade tip; touching the epoxy caused it to just crumble away.  Be careful because of course the circuit board, if epoxy, will also disintegrate.  It may take a few tries to find the best temperature and "touch".

Yeah, I'll try on some of the spots that doesn't have a huge blob of it.

[med6753]

Red LED displays and red panaplex displays are like a red dress on a woman that signals come and get me baby!   

Like the bull to the red cape. 

[Specmaster]

Oh, FFS.  Here, have some .pdf

Thanks, mnem. Yeah,  moment. Sorry, Spec, brain was elsewhere.

If everyone was to convert their documents into a pdf file then anyone on any platform can open and read the file without any fuss just by using a simple pdf reader which there are many and they are free on the internet. Many pdf creators are paid for programs but there is a lovely free one that works well and also a free pdf editor from the same source which can be downloaded from here www.cutepdf.com/. Once installed you activate the pdf writer in the same way as you select a printer, you select the print option of whatever program you use to create the document, Open Office, Notepad, MS Office, etc etc., select Cutepdf from the list and click print. It will save the file to your desktop as a normal pdf with all formatting preserved.

Perhaps this might be made a "sticky" for all to enjoy the simple means of exchanging text files without all the fuss?