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Re: 54615B Agilent Scope Amplitude Low When Measuring 120V AC

Bostonman
 

All very interesting input.

I've only measured the hot side of an AC plug a few times in my years. This most recent time was to show someone what 60Hz from an outlet looks like for real.

I don't remember every connecting the ground on the scope probe as I just leave it dangling.

Most likely this would all make more sense if I someone was physically showing the connections and/or how one could get injured. Personally it seems like very little can go wrong providing one doesn't slip with the probe and short both hot and neutral (or hot to Earth ground).

The other way to get injured would be to unplug the scope probe and accidentally touch the end while the probe is connected to the hot.

In any case, I don't plan to measure the hot directly again, but sense this scope has a roll over or something causing the higher voltage measurements to show lower than they are.
Re: Query about 40 GHz sig gens

 

¿ªÔÆÌåÓý

I have a Gigatronics generator that goes up to 75 GHz. It does sweep but no I/Q outputs. I would think even now that would be difficult over a wide frequency range. You may have to do that externally over a limited BW. 73 - Mike

?

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

?

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of ac0xu
Sent: Tuesday, November 16, 2021 9:00 PM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] Query about 40 GHz sig gens

?

I am looking for a 40 GHz sig gen. Do not need sweep. Would like basic internal modulation capabilities and I/Q inputs if possible.

?

Any recommendations for something affordable?? I have seen a lot of Anritsu siggens for sale on Ebay recently at plausible prices. I not e that Anritsu just seems to completely cut off support for older models - a policy which does not encourage me. Are Anritsu units reliable?

?

What about Agilent units?? Other brands?

?

Thanks-

?

Jim

?

?

?

?
Query about 40 GHz sig gens

 

I am looking for a 40 GHz sig gen. Do not need sweep. Would like basic internal modulation capabilities and I/Q inputs if possible.

Any recommendations for something affordable? I have seen a lot of Anritsu siggens for sale on Ebay recently at plausible prices. I not e that Anritsu just seems to completely cut off support for older models - a policy which does not encourage me. Are Anritsu units reliable?

What about Agilent units? Other brands?

Thanks-

Jim
Re: Sample preparation for Impedance Analyzer

 

Vladan, what frequency is this test fixture used up to? I assume its up to 1GHz?

Pete (another one)
G4GJL

On Tue, Nov 16, 2021 at 7:37 PM pianovt via <pianovt=[email protected]> wrote:
Hi Peter,

No, I have not used this fixture. It appears that it can accommodate two sizes of DUT. The rings look like dielectric spacers used to create a 50 Ohm line with the hole used for centering the measurement sample. The long screw is spring loaded so as to press the DUT electrodes against the shorted end of the transmission line on one end and the center conductor from the analyzer test port on the other end.

Vladan

Re: Sample preparation for Impedance Analyzer

 

Thanks Vladan; I think the hole is for the T connector to poke through?to make contact with the top of the APC7 adapter.?
The donuts are called springs in the pats list and there are only two sizes. They appear to be insulators with spring fingers on the bottom.
As you said they preserve the 50 ohm impedance.
Peter

On Mon, Nov 15, 2021 at 7:15 PM peter bunge <bunge.pjp@...> wrote:
Thanks Vladan.
That paper will be useful.
I also found the manual for the modern Keysight 16196A (851422.pdf download) to be useful.?
Have you ever used the coaxial test fixture?
It is coaxial as in 50 ohm impedance, I still do not know what the donuts are.
Peter

On Mon, Nov 15, 2021 at 6:34 PM pianovt via <pianovt=[email protected]> wrote:
Peter,

is a description of the measurement method and ratioanle.

Vladan

Re: Sample preparation for Impedance Analyzer

 

Hi Peter,

No, I have not used this fixture. It appears that it can accommodate two sizes of DUT. The rings look like dielectric spacers used to create a 50 Ohm line with the hole used for centering the measurement sample. The long screw is spring loaded so as to press the DUT electrodes against the shorted end of the transmission line on one end and the center conductor from the analyzer test port on the other end.

Vladan
Re: New member intro

 

On 11/16/21 11:47 AM, Chris Wilkson via groups.io wrote:
Yes, there are some compatibility issues.? I have 1 pair of ears
that
won't work with the installed handles.? The cutout angle is too
sharp.
These came extra in a bag with my 3456 meter and I was told they
would
work with the 850x gear.? They don't.
Are you sure they're actually HP System-II ears?
Also, don't forget that there are two types of ears for System-II
enclosures: one for use with handles, and the other without.
No, I'm not sure.? They were loose in a bag with no identification.
They look just like the ears on the 3456A meter which has handles and ears already installed.
Is the 3456A meter a HP System-II enclosure?? How can I tell?? Sure as heck looks the same as the 850xA VNA stuff.
The 3456A is System-II. For an easily-Googlable example of a System-I enclosure, look up the HP 8640B.

I do know there are 2 types of ears.
The ones I need have an acute angle cutout in the face that screws to the rack.? It's to accommodate the handles.
The other type doesn't have that cutout (I think....I've not seen them in person).
Yes, that's correct.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: New member intro

 

On Tue, Nov 16, 2021 at 05:55 AM, Dave McGuire wrote:
On 11/16/21 12:06 AM, Chris Wilkson via groups.io wrote:
Yes, there are some compatibility issues.? I have 1 pair of ears that
won't work with the installed handles.? The cutout angle is too sharp.
These came extra in a bag with my 3456 meter and I was told they would
work with the 850x gear.? They don't.
Are you sure they're actually HP System-II ears?

Also, don't forget that there are two types of ears for System-II
enclosures: one for use with handles, and the other without.
No, I'm not sure.? They were loose in a bag with no identification.
They look just like the ears on the 3456A meter which has handles and ears already installed.

Is the 3456A meter a HP System-II enclosure?? How can I tell?? Sure as heck looks the same as the 850xA VNA stuff.

I do know there are 2 types of ears.
The ones I need have an acute angle cutout in the face that screws to the rack.? It's to accommodate the handles.
The other type doesn't have that cutout (I think....I've not seen them in person).

Cheers,
Chris
Re: New member intro

 

On 11/16/21 12:06 AM, Chris Wilkson via groups.io wrote:
Yes, there are some compatibility issues.? I have 1 pair of ears that won't work with the installed handles.? The cutout angle is too sharp. These came extra in a bag with my 3456 meter and I was told they would work with the 850x gear.? They don't.
Are you sure they're actually HP System-II ears?

Also, don't forget that there are two types of ears for System-II enclosures: one for use with handles, and the other without.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: Removing the Adhesive From Hell

 

I recommend d-limonene.? It's orange peel extract and it's both a very good solvent for all kinds of glue.? It will take magic marker off hard surfaces.? If you buy the "Food-grade" version, you can take it as an antacid ( they make it in gel caps too).?

?
Re: 54615B Agilent Scope Amplitude Low When Measuring 120V AC

 

¿ªÔÆÌåÓý

If you use standard X10 'scope probes, one way to measure something like AC mains is to use both 'scope channels, set to ADD with one of the channels inverted.? This then gives a single trace on the 'scope which is in effect a differential measurement of the signal between the 2 probes.? With one probe on each side of the AC signal and the 'scope set to 5V/cm (and the probe earths 'earthed'), the sensitivity with a X10 probe is therefore 50V/cm, so 400V total, top to bottom of the screen.

?

With 120V AC, I would expect the P:P signals to be ~340V, within the 400V total range of the 'scope screen.

?

Just my 5p worth!

?

73, Mike,

Mike Stevens,

G8CUL/M0CUL/F4VRB.

?

From: [email protected] On Behalf Of Robert G8RPI via groups.io
Sent: 16 November 2021 10:32
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 54615B Agilent Scope Amplitude Low When Measuring 120V AC

?

One thing about Neils post,
the "earth" lead on the 'scope probe is not their for safety. It's just for signal fidelity.
The resistance and current rating of the lead is not adequate to provide protection against shocks or fire. I've seen more than one 'sope lead literally smoking over the years when somone (not me) made a bad connection.

Robert G8RPI.


Virus-free.

Re: 54615B Agilent Scope Amplitude Low When Measuring 120V AC

 

One thing about Neils post,
the "earth" lead on the 'scope probe is not their for safety. It's just for signal fidelity.
The resistance and current rating of the lead is not adequate to provide protection against shocks or fire. I've seen more than one 'sope lead literally smoking over the years when somone (not me) made a bad connection.

Robert G8RPI.
Re: How do I use these PSU output covers?

 


I have a couple of these supplies. When I'm using thin cables I bring them out of the slots on the lower face of the cover (I also use remote sensing with thin cables).?

If you don't want remote sensing you still need to loop back the sense inputs under that cover, or you'll see a significant output voltage error. Fitted by default by HP, but sometimes they and the annoyingly difficult to find connector get lost.

See attached pic.

--

Peter (G4VLC)



On Tue, 16 Nov 2021 at 09:52, Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:
On Tue, 16 Nov 2021 at 09:43, Dr. David Kirkby <drkirkby@...> wrote:
I have an HP 6674A PSU (normally 60 V 35 A), but mine with an option that increases the voltage to 70 V, but drops the current to 30 A. The output terminals should be covered by a cover, a photograph of which I attach. I am trying to figure out how Agilent expects these to be used.?

Oops, I forgot to attach one of the photos.

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

MonsterPSUsenseTerminals.jpg

Re: How do I use these PSU output covers?

 

On Tue, 16 Nov 2021 at 09:43, Dr. David Kirkby <drkirkby@...> wrote:
I have an HP 6674A PSU (normally 60 V 35 A), but mine with an option that increases the voltage to 70 V, but drops the current to 30 A. The output terminals should be covered by a cover, a photograph of which I attach. I am trying to figure out how Agilent expects these to be used.?

Oops, I forgot to attach one of the photos.

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

IMG_9509.jpg

How do I use these PSU output covers?

 

I have an HP 6674A PSU (normally 60 V 35 A), but mine with an option that increases the voltage to 70 V, but drops the current to 30 A. The output terminals should be covered by a cover, a photograph of which I attach. I am trying to figure out how Agilent expects these to be used.?

It looks like there are areas on these which you can break away to give some sort of hole that is not round. I am using cables which are about 6 mm in diameter. I am not bothered about remote sensing, the smaller holes would do for m4 6 mm diameter cables, but one can not fit a grommet or cable grand as there is insufficient room inside (see internal picture). If instead I use the larger holes, I will not find a grommet or cable gland that will take cables as small as 6 mm diameter.?

I am quite tempted to just drill two holes in this, and put a couple of cable glands suitable for a 6 mm diameter cables. But I suspect that the plastic might shatter if I try drilling it.? Someone else said don¡¯t bother with cable grands as this cover is too weak to take a good tug, so I might as well use grommets with? cable ties on the inside? to stop the cable pulling out. .?

I must be missing something, as Agilent seems to put a fair amount of effort into the design of his cover, but it seems virtually unusable to me.

Dave?


--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

IMG_9513.jpg
IMG_9510.jpg

Re: 54615B Agilent Scope Amplitude Low When Measuring 120V AC

 

You don't necessarily need isolated probes, you just need to have isolation between you and the test setup.

Please learn from my mistakes where I have fried probes and oscilloscopes. Here are some hard learned lessons:

1. If you aren't sure that your oscilloscope inputs are isolated then assume they are not. This is the correct assumption 99.99% of the time.
2. The ground lead on that probe is there protect you
3. The ground lead on the oscilloscope is also there to protect you
4. Resist the temptation to circumvent ground with isolation transformers for the oscilloscope power or by cutting the ground path.

Making a high fidelity high voltage measurement takes a bit of thought. The crudest method is to use 2 probe channels to make a crude differential probe. You connect the probe grounds together and not to the DUT. 1 probe goes to your signal and the other to your DUT ground. Then you subtract the two channels.

Better yet you can get a proper differential probe ($$) or a high voltage rated oscilloscope probe meant for this type of work ($$$). I personally prefer another option, using a battery powered oscilloscope ($-$$$) instead. These can be purchased with the same type of safety ratings as a DMM which a regulator oscilloscope could never achieve.

But to reiterate: the operator danger is when you are touching any part of the DUT or test setup. Avoid this when you can but setting up the measurement beforehand and then switch the DUT on safely.

Cheers,
Neil

On Mon, Nov 15, 2021, at 9:41 PM, Bostonman wrote:
As far as incorrect voltage, the 340V is pretty much spot on with the other oscilloscope, and the meter is a true RMS that is reading 120V AC.

So you're thinking that this scope has an acceptable error at this high voltage? This makes sense, and at least helps to know the scope isn't actually broken.

Isolated inputs is something I've never tinkered with, but have heard they should be used. Isolating equipment from the outlet is a concept I never grasped, and always been afraid of messing with it. Measuring line voltage was just for fun and not something I do often, but I guess it isn't the smartest thing to do.

Does a more affordable solution exist rather than $1k on that probe in the link?

Re: 54615B Agilent Scope Amplitude Low When Measuring 120V AC

Bostonman
 

As far as incorrect voltage, the 340V is pretty much spot on with the other oscilloscope, and the meter is a true RMS that is reading 120V AC.

So you're thinking that this scope has an acceptable error at this high voltage? This makes sense, and at least helps to know the scope isn't actually broken.

Isolated inputs is something I've never tinkered with, but have heard they should be used. Isolating equipment from the outlet is a concept I never grasped, and always been afraid of messing with it. Measuring line voltage was just for fun and not something I do often, but I guess it isn't the smartest thing to do.

Does a more affordable solution exist rather than $1k on that probe in the link?
RF probe tip

 

So I was perusing the HPAK 6632B manuals and under performance testing it requires a "1:1 probe with an RF tip."? Elsewhere under PARD testing it says?

"Set the oscilloscope's bandwidth limit to 20 MHz and use an RF tip on the oscilloscope probe".??

My question is what exactly is an RF probe tip?
Re: New member intro

 

Yes, there are some compatibility issues.? I have 1 pair of ears that won't work with the installed handles.? The cutout angle is too sharp.? These came extra in a bag with my 3456 meter and I was told they would work with the 850x gear.? They don't.
So I need to research the correct ears.? I have the original manuals for the VNA stack.? They should have the correct part numbers (I hope).? I just haven't had time to dig them out yet.
Re: Sample preparation for Impedance Analyzer

 

Thanks Vladan.
That paper will be useful.
I also found the manual for the modern Keysight 16196A (851422.pdf download) to be useful.?
Have you ever used the coaxial test fixture?
It is coaxial as in 50 ohm impedance, I still do not know what the donuts are.
Peter

On Mon, Nov 15, 2021 at 6:34 PM pianovt via <pianovt=[email protected]> wrote:
Peter,

is a description of the measurement method and ratioanle.

Vladan

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