Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1615402 times)

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Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29325 on: April 15, 2019, 01:06:54 pm »
At that point...isn't it just an open circuit for all intents and purposes?  :-DD

Depends on how many kV you poke at it ;) Circa 12kV off my neon transformer at 1.21GOhms is 0.01mA = 0.12 W

For Cal purposes I need to get some reasonably accurate points at well above 1M.

I'll just not, thankyouverymuch.  :scared:

1.21 GOhms ^-^

At that point...isn't it just an open circuit for all intents and purposes?  :-DD

Considering that old bench voltmeters have an input impedance of > 1 GΩ and even an old Keithley 614 electrometer has a 200 GΩ range, I guess you could say it's all relative.

True.

1.21 GOhms ^-^
At that point...isn't it just an open circuit for all intents and purposes?  :-DD

Ask a 555 timer that question. ;)

mnem
 :=\

 :-DD
 
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Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29326 on: April 15, 2019, 01:16:55 pm »
Today's cleanup background video. Baofeng leads to SDR leads to wireless data hacking. Interesting and uber nerdy.

https://youtu.be/N0p3_ES2dBU

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Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29327 on: April 15, 2019, 01:48:58 pm »
Very neat stuff...those ettus boards are not cheap either...
 

Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29328 on: April 15, 2019, 02:30:28 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.
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Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29329 on: April 15, 2019, 02:59:49 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

Yeah...I was thinking of getting a hackrf. A little more expensive but a lot less than ettus.

I was reading just the other day about how emergency services here in the states are switch to encrypted channels all around. Not just a few tactical channels for the fuzz...police, fire, and EMS all using encrypted links. :--
 

Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29330 on: April 15, 2019, 03:16:29 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

Yeah...I was thinking of getting a hackrf. A little more expensive but a lot less than ettus.

I was reading just the other day about how emergency services here in the states are switch to encrypted channels all around. Not just a few tactical channels for the fuzz...police, fire, and EMS all using encrypted links. :--

Our State Police and I assume most others have gone to encrypted some years ago. Emergency Services are generally still open https://www.radioreference.com/apps/db/?stid=152

We don't need a license for Tx on the standard 70cm band Channels but to use the 2m band including the channels used for Marine (and rescue) we need a license  :palm: While I am currently boatless apart from a Hobie Kayak a waterproof bag with a marine capable radio for $60 is still sensible, care factor of a fine if I am in the poo is Zero.
« Last Edit: April 15, 2019, 03:18:37 pm by beanflying »
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Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29331 on: April 15, 2019, 03:55:13 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

Yeah...I was thinking of getting a hackrf. A little more expensive but a lot less than ettus.

I was reading just the other day about how emergency services here in the states are switch to encrypted channels all around. Not just a few tactical channels for the fuzz...police, fire, and EMS all using encrypted links. :--

Our State Police and I assume most others have gone to encrypted some years ago. Emergency Services are generally still open https://www.radioreference.com/apps/db/?stid=152

We don't need a license for Tx on the standard 70cm band Channels but to use the 2m band including the channels used for Marine (and rescue) we need a license  :palm: While I am currently boatless apart from a Hobie Kayak a waterproof bag with a marine capable radio for $60 is still sensible, care factor of a fine if I am in the poo is Zero.

Yeah, the general sentiment in the stuff I've seen (and I tend to agree) is that taxpayer funded public servants shouldn't be on encrypted radio for general stuff. Tactical channels for SWAT teams and pursuits makes sense but everything else should be in the clear.

I can't sleep tonight, so kit building therapy time. I think the next kit I get has to be one of those giant transistor-level 555 timers.  ;D
 
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Offline bitseeker

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29332 on: April 15, 2019, 04:52:38 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

I got an RTL-SDR Blog V3 kit a few months ago. I don't know if it's better or worse than the NESDR or others. Apparently there are knockoffs of the RTL-SDR Blog V3, so I bought mine from the RTL-SDR Blog's eBay store.

For software, I use it with SDR#. It seems the original SDR# URL now redirects to airspy.com. I'm not sure what that means. You can still get SDR# on their download page, but it seems to be bundled with other stuff, now.

I got the dongle primarily to be able to check if a transmitter (e.g., RF remote) is functioning. But, using it to listen to FM and shortwave works as expected, too.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29333 on: April 15, 2019, 05:03:59 pm »
The old CRT has been cleaned up and is now a display piece. I'm considering breaking the exhaust tip to make it "safe" but I put it where it can't get knocked over (easily).  :-DD

Perhaps put it in an acrylic display case with a nice wood base.

+1

once I have more space I'm going to get some kind of a display case for my vacuum tube collection. Keep the dust off and the cats out...

As in https://entertaininghacks.wordpress.com/2016/03/09/rescuing-a-broken-tektronix-465-crt/ which also indicates how and where to cut.



Ought to upload a better image now I've got a decent camera.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29334 on: April 15, 2019, 05:19:15 pm »
Anyway, I am now the proud possessor of a Griffin Timer Scaler containing some of the same technology used in the world's oldest operating computer, the WITCH in TNMoC. Yes, it does work, and looks as retro cute as I would hope :) 

Since pictures are required, here's one at 1/250s:



And I still haven't got the blasted handle off!

Interesting. I've never seen such a thing. I like those little counters.

They are cute, and have the usual colour more often seen in delicious Panaplex displays.

They were frequently seen in the background of 50s and 60s movies/TV. The good ones showed them performing some scientific/military job. The bad ones (e.g. excreble SF / cold war propaganda) used them as blinkenlights.

Anyway, feast your eyes here http://www.tnmoc.org/special-projects/harwell-dekatron-witch including a video of the computer being rebooted with some of its original designers. A shorter version is


There are lies, damned lies, statistics - and ADC/DAC specs.
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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29335 on: April 15, 2019, 05:21:53 pm »
At that point...isn't it just an open circuit for all intents and purposes?  :-DD

Depend on the humidity and voltage :)
There are lies, damned lies, statistics - and ADC/DAC specs.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29336 on: April 15, 2019, 05:25:12 pm »


Since pictures are required, here's one at 1/250s:



And I still haven't got the blasted handle off!
What type of connector is the one labeled 'GM'?

Completely unknown, but I suspect that it may carry high voltage at high output impedance, for direct connection to a geiger-muller tube.

I'll have a better idea if/when I can remove the carry handle, which looks like it might be bent internally :(
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29337 on: April 15, 2019, 05:39:56 pm »
This evenings TEA Foot making tools include Fusion with a Helping hand from a Coopers Stout or two or ....  :popcorn:

Rough Prototype as per the photo is on the printer.
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Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29338 on: April 15, 2019, 06:01:54 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

I got an RTL-SDR Blog V3 kit a few months ago. I don't know if it's better or worse than the NESDR or others. Apparently there are knockoffs of the RTL-SDR Blog V3, so I bought mine from the RTL-SDR Blog's eBay store.

For software, I use it with SDR#. It seems the original SDR# URL now redirects to airspy.com. I'm not sure what that means. You can still get SDR# on their download page, but it seems to be bundled with other stuff, now.

I got the dongle primarily to be able to check if a transmitter (e.g., RF remote) is functioning. But, using it to listen to FM and shortwave works as expected, too.

How does the RTL-SDR do at lower frequencies? The NooElec NESDR is specced at 65MHz bottom end and they sell an up converter for covering HF and the lower end.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29339 on: April 15, 2019, 06:59:45 pm »
Upconvert 120MHz up with DBM with a signal generator...



You can get SMD 120MHz oscillator modules that probably act as a decent enough LO like Epson Q33519E40002112. Probably about £5 of stuff and 30 minute build :D



Edit: well I used the HP 400E for the first time properly last night. The thing is excellent. Sure it's average responding but it's amazingly good bit of kit. I built a upper-sideband CIO for the superhet transceiver I am working on. Trying to build this entire thing with just a DMM, counter, AC voltmeter and power supply.
« Last Edit: April 15, 2019, 07:16:02 pm by bd139 »
 

Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29340 on: April 15, 2019, 07:28:01 pm »
Upconvert 120MHz up with DBM with a signal generator...
...
You can get SMD 120MHz oscillator modules that probably act as a decent enough LO like Epson Q33519E40002112. Probably about £5 of stuff and 30 minute build :D



Edit: well I used the HP 400E for the first time properly last night. The thing is excellent. Sure it's average responding but it's amazingly good bit of kit. I built a upper-sideband CIO for the superhet transceiver I am working on. Trying to build this entire thing with just a DMM, counter, AC voltmeter and power supply.

Most of the stuff I want is above HF for I am unlikely to need a converter.

Todays evilbay tasty item. Classy and Clean early 60's HP Oscillator. Cheap for the collector in Melbourne. $220 AU pesos eBay auction: #163649071599

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29341 on: April 15, 2019, 07:40:25 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

Yeah...I was thinking of getting a hackrf. A little more expensive but a lot less than ettus.

I was reading just the other day about how emergency services here in the states are switch to encrypted channels all around. Not just a few tactical channels for the fuzz...police, fire, and EMS all using encrypted links. :--

Not so far in my County. While they have a very efficient and integrated 911 system their radio system is still in the stone age. And that's good because I can listen in.  :-DD Up until a year ago the county wide fire dispatch was still on 33.48Mhz FM. They just recently moved to 155.200Mhz FM in the clear. Many of the fire ground radios are still centered around 46Mhz FM. County wide dispatch for all police agencies, State Police, sheriff, and local agencies is 155.025Mhz simplex. Again, in the clear. Now many of the local police depts are on 800Mhz trunk for their own headquarters but for county they talk at 155.025Mhz.

Now I know one of these days it's all gonna go to digital encryption and my scanner will be obsolete. But so far the politicians in this county don't want to spend the money so I benefit.  :-+ 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29342 on: April 15, 2019, 07:47:48 pm »
We're all Motorola TETRA here at the moment. Coordinated across all emergency services. What's cool is the TETRA sets work underground on the public transport as well now. Ambulance driver gets a call at a tube station and can relay stuff and call for assistance while they're underground etc. This goes as far as working in the tunnels between stations. Same with police / BTP / fire etc.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29343 on: April 15, 2019, 07:49:40 pm »
In other news. At about 0400 hours this morning we had our first thunderstorm of the year. Not too violent but enough to make itself known. Scattered power outages and trees down reported. And currently under a "Tornado Watch" until 0700 hours.  :scared:

Unusually warm over night for this time of year. About 15 C. I guess Spring is finally here.  :-+
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Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29344 on: April 15, 2019, 07:54:59 pm »
We're all Motorola TETRA here at the moment. Coordinated across all emergency services. What's cool is the TETRA sets work underground on the public transport as well now. Ambulance driver gets a call at a tube station and can relay stuff and call for assistance while they're underground etc. This goes as far as working in the tunnels between stations. Same with police / BTP / fire etc.

Believe it or not....for all the money they spend on security.....the NYC 911 radio system is still for the most part on VHF and in the clear. It's too bad I'm too far away to listen in because I'm sure I'll hear some interesting stuff.  ;D
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Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29345 on: April 15, 2019, 08:07:17 pm »
Very neat stuff...those ettus boards are not cheap either...

Seems they are now owned by National Instruments won't be helping. I think I will settle for one of these eBay auction: #172813499296 and maybe add a discone antenna (unless anyone has a better suggestion?) of some sort to it at some stage. I mainly want access to weather, local emergency services and airband.

Yeah...I was thinking of getting a hackrf. A little more expensive but a lot less than ettus.

I was reading just the other day about how emergency services here in the states are switch to encrypted channels all around. Not just a few tactical channels for the fuzz...police, fire, and EMS all using encrypted links. :--

Not so far in my County. While they have a very efficient and integrated 911 system their radio system is still in the stone age. And that's good because I can listen in.  :-DD Up until a year ago the county wide fire dispatch was still on 33.48Mhz FM. They just recently moved to 155.200Mhz FM in the clear. Many of the fire ground radios are still centered around 46Mhz FM. County wide dispatch for all police agencies, State Police, sheriff, and local agencies is 155.025Mhz simplex. Again, in the clear. Now many of the local police depts are on 800Mhz trunk for their own headquarters but for county they talk at 155.025Mhz.

Now I know one of these days it's all gonna go to digital encryption and my scanner will be obsolete. But so far the politicians in this county don't want to spend the money so I benefit.  :-+

I still have an old Vehicle mounted 25W system from our Forest management department in a box 'somewhere' (Department of Name Changes for the locals  :palm: ) Was on 32Mhz and we used a bunch of them 'slightly' illegally on a cross Desert trip with some 5W handhelds 8 or 9 years ago as well. Great range between vehicles but the handhelds were fairly sucky.

The influx of these Baofeng cheapies and similar that go outside the standard legal unlicensed channels might see out Emergency services go encrypted to avoid the idiots.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29346 on: April 15, 2019, 08:48:18 pm »
We're all Motorola TETRA here at the moment. Coordinated across all emergency services. What's cool is the TETRA sets work underground on the public transport as well now. Ambulance driver gets a call at a tube station and can relay stuff and call for assistance while they're underground etc. This goes as far as working in the tunnels between stations. Same with police / BTP / fire etc.

Believe it or not....for all the money they spend on security.....the NYC 911 radio system is still for the most part on VHF and in the clear. It's too bad I'm too far away to listen in because I'm sure I'll hear some interesting stuff.  ;D
Yeah you sure would, I used to listen into our emergency services when they were in the open on VHF especially exciting if something was happening your own area as well but of course now that they are using TETRA I can no longer do that, hmmm just wish someone would develop a scanner that could cover TETRA as well the military air bands and was reasonably priced. I don't think that I have ever heard of anyone selling a radio capable of receiving and decoding TETRA ?
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29347 on: April 15, 2019, 08:56:55 pm »
Taking that trolley to Aunby to pick up your snatches there?

Nah. They've got forklifts.

But it does mean there are only two justifications for me to go to Dunstable: to unload stuff and then visit TNMoC.

Benefit of flogging stuff at Dunstable is you don't have to lug booty through woods and across fields.
Somehow I doubt that they will need the forklift to fetch my two Solartron 7150s for me  :-DD

WTF do you normal buy to warrant them to use the Forklift, do you buy enough gear to have it put on a pallet? and what do you then do with it afterwards, take to hamfests and move it on? :-//
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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29348 on: April 15, 2019, 09:01:45 pm »
Taking that trolley to Aunby to pick up your snatches there?

Nah. They've got forklifts.

But it does mean there are only two justifications for me to go to Dunstable: to unload stuff and then visit TNMoC.

Benefit of flogging stuff at Dunstable is you don't have to lug booty through woods and across fields.
Somehow I doubt that they will need the forklift to fetch my two Solartron 7150s for me  :-DD

WTF do you normal buy to warrant them to use the Forklift, do you buy enough gear to have it put on a pallet? and what do you then do with it afterwards, take to hamfests and move it on? :-//

Everything I buy is potentially for me, but since I have limited space I have to move some stuff on.

I don't buy anything that I can't carry up steps on my own :) That means portable spectrum analysers are OK, but big SA's and network analysers aren't.

A 7 decade KVD is OK, just, but I'm wary of Fluke calibrators :(
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29349 on: April 15, 2019, 09:05:22 pm »
Well there's part of the problem. 10-18-14-8V all at once  :o Removed and all happy and stable just in need of a good cal.it seems.

Seems a replacement battery is over $50 USD  :wtf:

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