Test Equipment Anonymous (TEA) group therapy thread

[Kilo Tango]

I went on TTi's website the other day and asked for a price for a genuine charger. They haven't got back yet.

I think they are only £10 but still to add postage plus VAT.

Ken

[Specmaster]

There’s also 1.7. It’s either 1.4 or 1.7.

I wish there was a better DC jack standard.

Really ? 

So let's standardise on something like 2.1 x 5.5......yeah right, it's way overkill for a Bluetooth hands-free earpiece.
Horses for courses.

Well it certainly is not 2.1, thats quite large in comparison. The actual plug is a tad larger then the ones fitted to Nokia phone chargers.

Scroll through to find the right one:
https://www.jaycar.co.nz/interconnect/plugs-sockets-adaptors/dc-power/c/300I
Calipers, some drills or various wire diameters and you'll have it sorted in minutes.
It ain't rocket science.

OK, then, I have dug out jewellers screwdrivers and it seems that a 1.4mm can be pushed down the tube of the plug on my power pack but it tight so therefore the correct size is 1.3mm https://en.wikipedia.org/wiki/Coaxial_power_connector

[Specmaster]

It most definitely is Type E: 3.4 mm OD, 1.3 mm ID plug that you need.

[tautech]

There’s also 1.7. It’s either 1.4 or 1.7.

I wish there was a better DC jack standard.

Really ? 

So let's standardise on something like 2.1 x 5.5......yeah right, it's way overkill for a Bluetooth hands-free earpiece.
Horses for courses.

2.1x5.5 connectors are stupid. Most are quoted to 1A max.

So ? 
Look at your LAN switch, modem, cordless phone station etc and who the f**k would suggest using other than what's in them currently.

Like I said, horses for courses.

[Specmaster]

Well, I'm telling you that it is a 3.4 x 1.3 dc plug for certain because I have measured it and it is confirmed by WiKi as a standard size DC jack.

Here is a snap showing a signal of 215.121KHz being fed to my 2 TF930's and also to a nondescript Chinese cheap frequency counter from Ebay which displays remarkable accuracy given it cheap price of  £12.68 complete with the acrylic case.

In case you struggle to read the displays, it reads like this,
Function Gen is 215.121KHz
Top TF930 is 215.894KHz
Chinese counter is 215.516KHz
and bottom TF930 is 215.128KHz which is the nearest to the original signal and also clearly demonstrates the poor readability of the unlit LCD screens at various angles and that was with a 22w magnifier lamp just to my right facing the screens and also with 2 x 8W LED strips mounted on the wall behind me, just 4 feet away from the counters and the camera had flash switched on. Those screen would most certainly benefit from some form of internal lighting.

[Specmaster]

I don't know if anyone has noticed yet, but as predicted yesterday, we would shortly be the 3rd most popular thread, well we are currently (in terms of pages per thread) neck and neck at 204 pages each with the what did you purchase today thread in General Chat.

[Specmaster]

BD139, the part number in CPC is PW04092 for a 2.1 x 5.5 adaptor to 1.3 x 3.5 plug @ £1.79 each and is in stock.

This will any 5v power brick you have with a 5.5 x 2.1 plug fitted and convert it to fit the TF930 without having to cannibalise the original power supply, any good? 

[bd139]

It most definitely is Type E: 3.4 mm OD, 1.3 mm ID plug that you need.

Thank you - will order. Much appreciated!

So ? 
Look at your LAN switch, modem, cordless phone station etc and who the f**k would suggest using other than what's in them currently.

Like I said, horses for courses.

My switch (D-Link DES-something-or-other) has an IEC connector. The APs are both PoE, the VDSL comes in to an HP microserver which has a PCI card in it (VigorNIC 132) and I don't use a land line.

Literally the only thing I have with one of them in it is the lamp and the connector keeps falling out. 

Well, I'm telling you that it is a 3.4 x 1.3 dc plug for certain because I have measured it and it is confirmed by WiKi as a standard size DC jack.

Here is a snap showing a signal of 215.121KHz being fed to my 2 TF930's and also to a nondescript Chinese cheap frequency counter from Ebay which displays remarkable accuracy given it cheap price of  £12.68 complete with the acrylic case.

In case you struggle to read the displays, it reads like this,
Function Gen is 215.121KHz
Top TF930 is 215.894KHz
Chinese counter is 215.516KHz
and bottom TF930 is 215.128KHz which is the nearest to the original signal and also clearly demonstrates the poor readability of the unlit LCD screens at various angles and that was with a 22w magnifier lamp just to my right facing the screens and also with 2 x 8W LED strips mounted on the wall behind me, just 4 feet away from the counters and the camera had flash switched on. Those screen would most certainly benefit from some form of internal lighting.

What do they read independently? Frequency discrepancy there is quite large!

BD139, the part number in CPC is PW04092 for a 2.1 x 5.5 adaptor to 1.3 x 3.5 plug @ £1.79 each and is in stock.

This will any 5v power brick you have with a 5.5 x 2.1 plug fitted and convert it to fit the TF930 without having to cannibalise the original power supply, any good? 

I've only got about 20 of them with micro USB's on them so was going to snip one of those off. Literally my entire house is devoid of barrel connectors (intentionally!)

Thanks for the suggestion however

[Specmaster]

OK then, the plug is CN05721 pack of 5 £1.10.

To answer what do they read independently, the same as per photograph, there is no interaction between them. If I connect the Velleman (Mastech really) underneath the bottom TF930 then the reading on that unit goes up nearer to the top one and surprisingly the Velleman is almost 215.122KHz.

So the Velleman affects the TF930 adversely if stacked on top of each other, but the cheaper counters do give a bloody good account of themselves really all things considered but their overall feature set is nowhere the same, the TF930 are by far the most versatile units but it does seem that the top TF930 needs a very slight tweak to pull it into line a bit more.

In reality, is that small error going affect much? I doubt it     

[bd139]

Thanks - that's exactly what I have in my basket

Now to find £4.08 of stuff to fill the rest of the basket to get free delivery!

Sounds like transmission line, impedance or termination fun is going on there. They should read very closely if driven from the same output.

Certainly don't have anything against cheaper counters; they're pretty good.

[ChrisLX200]

A man with one counter knows what frequency it is, a man with three counters...

[Specmaster]

A man with one counter knows what frequency it is, a man with three counters...

Make that 4 counters 

[ChrisLX200]

A man with one counter knows what frequency it is, a man with three counters...

Make 4 counters 

LOL, my mistake... Still, get yourself a GPSDO or Rb source and tie them together with a 10MHz reference!

[bitseeker]

A man with one counter knows what frequency it is, a man with three counters...

Make that 4 counters 

...sometimes wishes he only had one.

[Cubdriver]

A man with one counter knows what frequency it is, a man with three counters...

Make that 4 counters 

...sometimes wishes he only had one.

   I'm afraid to count my counters.  And now have a different variant of the HP 5214L (an M36 5214L, with two sets of preset switches) on order to join the collection.  Damn you, evilBay, you make my credit card cry!

-Pat

[Specmaster]

A man with one counter knows what frequency it is, a man with three counters...

Make that 4 counters 

...sometimes wishes he only had one.

Just like multimeters, you can never have to many.
Just been running some tests on them in 1MHz steps upto the max of my function generator of 25MHz and they are all pretty stable and close to the input frequency and the little £13 ebay chinese one is really bloody good value for money and is very accurate to boot. It lacks the added functionality of the others though if thats whats required to do the job, but for pure frequency counting above 100KHz is brilliant, below that its a bit how you doing but near enough I suppose for radio work at least.

Cant tie them together though as only the TTi's have a ref input, the Velleman (Mastech 6100) has a ref output of 10MHz, so that one could tie the TTi's together 

[Specmaster]

What do they read independently? Frequency discrepancy there is quite large!

I did further tests in 1MHz steps on each one in turn using the same function gene and lead to play fair and the results are extremely close with TF930's differing on the least significant figures, as you would expect and the Velleman and also the cheapo chinese counter almost matching all the way through, in fact it pretty darned close to the performance of the TF930's. Its downfall is its limited functionality.

So there was some of the connection / transmission losses etc coming into play before.

[Specmaster]

A man with one counter knows what frequency it is, a man with three counters...

Make that 4 counters 

Oops, make that 5 counters because the function gene can be used as one if needed 

[bd139]

Transmission lines are dicks

GPSDO is on my project list. I wonder if I can get it inside the TF930 case as well. The BNC for the reference input is available on the back of the main PCB so blank off the ref input on the front and add a ref out on the back panel (or three and a distribution amplifier) and something to drive both the GPSDO in standby (for locking purposes) and the counter. The 930 will lock on the external ref on power up apparently.

Also might add some weight to it!

Now to find a decent GPS module with 1pps output and build a PLL!

FFS I jut created another project I don’t have time for

[Specmaster]

Simple, accept the default accuracy and project gone...

[bd139]

I’ll limit myself to an external GPSDO i think

[bitseeker]

FFS I jut created another project I don’t have time for

That's a different group: Project Creators Anonymous (closely related to Project Starters Anonymous).

[beanflying]

WooHoo Saturday Postie Santa arrived, new toys to play with over the weekend 

[Specmaster]

WooHoo Saturday Postie Santa arrived, new toys to play with over the weekend 

You're lucky, still waiting for a lot of toys to arrive.

[beanflying]

You will have to survive the weekend living vicariously through the delight and joy of others. Oh and the odd photo or two