FFT analyzer recommendations

[Phil Hobbs]

Hi, all,

I need another FFT analyzer. I really like my HP 35660A, but it only
goes up to 100 kHz (50 kHz for two-channel measurements). I'd really
like one that goes up to at least 10 MHz, and can do the same sorts of
stuff, especially display noise spectral density in different units on
different scales and perform frequency response testing easily.

There are a bunch of USB-style things, which might be okay as long as
they have Linux software available.

What I really want is a smallish boat anchor with two channels, 14-16
bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
that can talk to USB sticks.

Any faves?

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

[George Herold]

I think you should buy one of the Rigol SA's and report back.
Specifically the cheap DSA815-TG.
https://www.rigolna.com/products/spectrum-analyzers/dsa800/

George H.

[pcdh...@gmail.com]

The Rigols are RF spectrum analyzers, and I already have three of those. I'm looking for a more modern version of the HP 89410A, basically.

Cheers

Phil Hobbs

[George Herold]

On Friday, February 16, 2018 at 12:35:18 PM UTC-5, pcdh...@gmail.com wrote:
> The Rigols are RF spectrum analyzers, and I already have three of those. I'm looking for a more modern version of the HP 89410A, basically.

Oh are the Rigols OK? I want a SA that goes above 100k Hz too.
~10 MHz would be enough for lots of stuff. Are the Rigols any use
in the 1 MHz - 10 MHz range?

George h.
>
> Cheers
>
> Phil Hobbs

[Phil Hobbs]

Entry level SAs are all SDR-based these days, so they make nice pictures
and are pretty flexible compared with traditional ones, and in the
low-frequency range they're probably fine. I hang on to my 8566es
because their close-in phase noise is unbeatable due to their YIG-tuned
oscillators and filters, but that really only becomes important above
~100 MHz.

If you're OK with a noise floor around -80 dB from full scale, the Rigol
is probably fine, and it's not at all a bad price.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

https://hobbs-eo.com

[George Herold]

On Friday, February 16, 2018 at 3:22:51 PM UTC-5, Phil Hobbs wrote:
> On 02/16/2018 01:48 PM, George Herold wrote:
> > On Friday, February 16, 2018 at 12:35:18 PM UTC-5, pcdh...@gmail.com wrote:
> >> The Rigols are RF spectrum analyzers, and I already have three of those. I'm looking for a more modern version of the HP 89410A, basically.
> >
> > Oh are the Rigols OK? I want a SA that goes above 100k Hz too.
> > ~10 MHz would be enough for lots of stuff. Are the Rigols any use
> > in the 1 MHz - 10 MHz range?
> >
> > George h.
>
> Entry level SAs are all SDR-based these days, so they make nice pictures
> and are pretty flexible compared with traditional ones, and in the
> low-frequency range they're probably fine. I hang on to my 8566es
> because their close-in phase noise is unbeatable due to their YIG-tuned
> oscillators and filters, but that really only becomes important above
> ~100 MHz.
>
> If you're OK with a noise floor around -80 dB from full scale, the Rigol
> is probably fine, and it's not at all a bad price.

Thanks Phil, 80 dB is better than the 50 dB I get with my 'scope
FFT.

GH

[pcdh...@gmail.com]

Okay, so I put in an eBay 'best offer' on an HP 89441A vector signal analyzer with the two-input option. We'll see!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Feb 16

[Gerhard Hoffmann]

Am 18.02.2018 um 01:44 schrieb pcdh...@gmail.com:
> Okay, so I put in an eBay 'best offer' on an HP 89441A vector signal analyzer with the two-input option. We'll see!
>

I have written a program that controls that thing over the network
and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads
the results, combines them and plots them with gnuplot.

One needs a converter box from coax ethernet to contemporary network,
then one just opens port 5000-something on 192.168.178.111 and simply
reads and writes GPIB-strings. And the coax needs 2 terminations, even
when the "cable" is only 5 inch long. :-)

No need for GPIB cards and semi-supported drivers.

These measurements of voltage regulator noise have been done with it:
<
https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/
>


Just in case you win it and are interested.

cheers, Gerhard

[pcdh...@gmail.com]

>I have written a program that controls that thing over the network
>and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads
>the results, combines them and plots them with gnuplot.

>One needs a converter box from coax ethernet to contemporary network,
>then one just opens port 5000-something on 192.168.178.111 and simply
>reads and writes GPIB-strings. And the coax needs 2 terminations, even
>when the "cable" is only 5 inch long. :-)

>No need for GPIB cards and semi-supported drivers.

>These measurements of voltage regulator noise have been done with it:
<
https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/
   >


>Just in case you win it and are interested.

Hi, Gerhard,

I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for it, but that'll be fun.

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

https://hobbs-eo.com

[JM]

On 21/02/2018 01:29, pcdh...@gmail.com wrote:
>> I have written a program that controls that thing over the network
>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads
>> the results, combines them and plots them with gnuplot.
>
>> One needs a converter box from coax ethernet to contemporary network,
>> then one just opens port 5000-something on 192.168.178.111 and simply
>> reads and writes GPIB-strings. And the coax needs 2 terminations, even
>> when the "cable" is only 5 inch long. :-)
>
>> No need for GPIB cards and semi-supported drivers.
>
>> These measurements of voltage regulator noise have been done with it:
> <
> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/
> >
>
>
>> Just in case you win it and are interested.
>
> Hi, Gerhard,
>
> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for it, but that'll be fun.
>
> Thanks
>
> Phil Hobbs
>

Note that the software options can easily be unlocked on these (although
they would be of little use for your intended application).

[Phil Hobbs]

The cell-phone stuff won't help much, but I'm hoping that I can turn on
the AYB (spectrogram and waterfall) option without scrooching it.
(Option AY8, the internal source, would be useful too, but it's probably
a HW option.)

The software one should be no big issue as long as the floppy drive
works reliably.

Cheers

[Gerhard Hoffmann]

Mine has most options, but I'm not sure about the waterfall.
What is missing is the source up converter for the RF section.
But for RF I have a real VNA.

That thing has so much parameters to set up that I wrote the program
to control it remotely very soon. I had to use a pre-flight check list
otherwise.

Important options are dual channel, needed for cross correlation,
source for Bode plots etc and memory extension.

My program is in C, under Linux. It probably can be compiled under
Windows, too. You'll need a lot of gain to mask the noise in the 1/f
region. That eats into the dynamic range.

I'll remove the most embarrassing FIXMEs over the weekend, a good
opportunity to clean it up :-)

cheers, Gerhard

[Phil Hobbs]

On 02/16/2018 09:59 AM, Phil Hobbs wrote:
> Hi, all,
>
> I need another FFT analyzer.  I really like my HP 35660A, but it only
> goes up to 100 kHz (50 kHz for two-channel measurements).  I'd really
> like one that goes up to at least 10 MHz, and can do the same sorts of
> stuff, especially display noise spectral density in different units on
> different scales and perform frequency response testing easily.
>
> There are a bunch of USB-style things, which might be okay as long as
> they have Linux software available.
>
> What I really want is a smallish boat anchor with two channels, 14-16
> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
> that can talk to USB sticks.

So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
that it doesn't have the serial cable--is it a regular straight-through
9-pin cable, or something weird?

Thanks

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

https://hobbs-eo.com

[Phil Hobbs]

Hi, Gerhard,

Thanks, that would be great. We're an all-Linux shop round here, so no
worries there.

[Gerhard Hoffmann]

Am 21.02.2018 um 02:29 schrieb pcdh...@gmail.com:

>
> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for it, but that'll be fun.
>

I'm working on a chopper preamp that should be flat down to at least
100mHz, but it seems that I cannot verify that with the 89441A.

It works with parallel ADG819 analog switches, step up transformers,
more low noise gain with ADA4898s on 500 KHz, synchronous demodulator
back to baseband and some more gain.

A Xilinx Coolrunner II generates the timing from a 100 MHz osc.
It looks like I get 120 pV/rtHz.

The main problem is the ringing of the step up transformer. I re-wired
some Macom and Pulse SMD transformers under the microscope using 50u wire.

That was no fun. 1/2 :-)

cheers, Gerhard

[Gerhard Hoffmann]

Am 23.02.2018 um 20:15 schrieb Phil Hobbs:

> So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
> that it doesn't have the serial cable--is it a regular straight-through
> 9-pin cable, or something weird?

I also had to make the cable myself.
It wasn't much work, and it is known how to do it.

[k...@notreal.com]

On Fri, 23 Feb 2018 14:15:48 -0500, Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>On 02/16/2018 09:59 AM, Phil Hobbs wrote:
>> Hi, all,
>>
>> I need another FFT analyzer.  I really like my HP 35660A, but it only
>> goes up to 100 kHz (50 kHz for two-channel measurements).  I'd really
>> like one that goes up to at least 10 MHz, and can do the same sorts of
>> stuff, especially display noise spectral density in different units on
>> different scales and perform frequency response testing easily.
>>
>> There are a bunch of USB-style things, which might be okay as long as
>> they have Linux software available.
>>
>> What I really want is a smallish boat anchor with two channels, 14-16
>> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
>> that can talk to USB sticks.
>
>So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
>that it doesn't have the serial cable--is it a regular straight-through
>9-pin cable, or something weird?

The DOCs are online, if you don't have them. It appears to be a
common serial cable (but who knows how many pins are used). There is
also a comment about the EMI suppression ferrite position.

[Phil Hobbs]

On 02/23/2018 03:17 PM, Gerhard Hoffmann wrote:
> Am 21.02.2018 um 02:29 schrieb pcdh...@gmail.com:
>
>>
>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for
>> it, but that'll be fun.
>>
>
> I'm working on a chopper preamp that should be flat down to at least
> 100mHz, but it seems that I cannot verify that with the 89441A.

I have a 35665A, whose 1/f is pretty good.

>
> It works with parallel ADG819 analog switches, step up transformers,
> more low noise gain with ADA4898s on 500 KHz, synchronous demodulator
> back to baseband and some more gain.
>
> A Xilinx Coolrunner II generates the timing from a 100 MHz osc.
> It looks like I get 120 pV/rtHz.

At 0.1 Hz? Awesome!

>
> The main problem is the ringing of the step up transformer. I re-wired
> some Macom and Pulse SMD transformers under the microscope using 50u wire.
>
> That was no fun.    1/2 :-)

I bet. I once spent about three weeks repairing metal-patterned PVDF
pyroelectric films with silver paint for a customer demo, so I feel your
pain.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

[JM]

On 23/02/2018 17:11, Phil Hobbs wrote:
> On 02/23/2018 11:15 AM, JM wrote:
>> On 21/02/2018 01:29, pcdh...@gmail.com wrote:
>>>> I have written a program that controls that thing over the network
>>>> and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads
>>>> the results, combines them and plots them with gnuplot.
>>>
>>>> One needs a converter box from coax ethernet to contemporary network,
>>>> then one just opens port 5000-something on 192.168.178.111 and simply
>>>> reads and writes GPIB-strings. And the coax needs 2 terminations, even
>>>> when the "cable" is only 5 inch long. :-)
>>>
>>>> No need for GPIB cards and semi-supported drivers.
>>>
>>>> These measurements of voltage regulator noise have been done with it:
>>> <
>>> https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/
>>>
>>> >
>>>
>>>
>>>> Just in case you win it and are interested.
>>>
>>> Hi, Gerhard,
>>>
>>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for
>>> it, but that'll be fun.
>>>
>>> Thanks
>>>
>>> Phil Hobbs
>>>
>>
>> Note that the software options can easily be unlocked on these (although
>> they would be of little use for your intended application).
>
> The cell-phone stuff won't help much, but I'm hoping that I can turn on
> the AYB (spectrogram and waterfall) option without scrooching it.

You'll be able to do that.

> (Option AY8, the internal source, would be useful too, but it's probably
> a HW option.)
>

Oh, you got an 89431A as well as a 89410A? You'll soon be welding a
couple of 42H racks on top of each other to save on floor space.

[Phil Hobbs]

I got the complete 89441A 2.65 GHz gizmo. I'll move my spare Tek11801C
out of the rack to make space. ;)

You can fit a lot in a 7-foot EIA rack.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

[Phil Hobbs]

Speaking of which, I could use a shorter four-post instrument rack with
adjustable rails, but they never seem to come up on eBay--just the
flimsy audio and gigundo server racks.

Any sourcing suggestions? I bought my present HP one from long-lost SED
regular ecnerwal in about 2009.

[Long Hair]

Phil Hobbs wrote:

>
> Any sourcing suggestions? I bought my present HP one from long-lost SED
> regular ecnerwal in about 2009.
>

Hunt up an old Tek rolling cart. They have two vertical pillars which
are std 19" wide opening. Good heavy duty cart with 600Lb smooth rool
casters. Most come with shelves and drawers too (which can be re-sold
if not desired).

[Phil Hobbs]

I'm from back then too, so I remember them fondly. (Well, the 7000
series, not the 5XX tube monsters.)

You couldn't fit a stack of 19" rack equipment on a 7000-series cart,
because it's too narrow. I haven't used the ginormo tube-scope carts,
but in general tippable carts are way too short and unstable. It's hard
to see how you could get more than one or (at most) two large
instruments on those before the tipping motion became dicey.

I've got instruments on Ikea kitchen carts, which are fine, but I need a
second real rack.

[Long Hair]

Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote in
news:arudnYqcBfI1jQ_H...@supernews.com:

> On 02/24/2018 08:09 PM, Long Hair wrote:
>> Phil Hobbs wrote:
>>
>>>
>>> Any sourcing suggestions? I bought my present HP one from long-lost
>>> SED regular ecnerwal in about 2009.
>>>
>>
>> Hunt up an old Tek rolling cart. They have two vertical pillars
>> which
>> are std 19" wide opening. Good heavy duty cart with 600Lb smooth
>> rool casters. Most come with shelves and drawers too (which can be
>> re-sold if not desired).
>>
> I'm from back then too, so I remember them fondly. (Well, the 7000
> series, not the 5XX tube monsters.)
>
> You couldn't fit a stack of 19" rack equipment on a 7000-series cart,
> because it's too narrow. I haven't used the ginormo tube-scope carts,
> but in general tippable carts are way too short and unstable. It's
> hard to see how you could get more than one or (at most) two large
> instruments on those before the tipping motion became dicey.
>
> I've got instruments on Ikea kitchen carts, which are fine, but I need
> a second real rack.
>
> Cheers
>
> Phil Hobbs
>

These were not "tipping carts". These monsters could mount a friggin
shuttle cockpit console. ;-)

The K420 series. I have a couple that have five foot tall pillars on
them. The casters are to die for in mobility terms.

https://www.ebay.com/itm/Tektronix-K420-Instrument-Workstation-
Cart/332365981238

[pcdh...@gmail.com]

Floor space is a bit of an issue, because we've got a lot of good stuff:

https://electrooptical.net/Lab_Tour/

https://electrooptical.net/Equipment

So I really need a shorter version of the big HP rack in the photos.

[JM]

I designed a CSEM receiver 20 or so years ago with sub 100pV noise
(0.01-15Hz BW and 120dB overall gain) with a similar architecture.
These worked with Ag-AgCl field sensors with a source resistance of
about 5 ohms.

I'd expect modern CSEM receivers to have improved on that - a google or
patent search might give you some ideas?

[Winfield Hill]

JM wrote...

>
>On 23/02/2018 20:17, Gerhard Hoffmann wrote:
>> Am 21.02.2018 um 02:29 schrieb pcdh...@gmail.com:
>>
>>>
>>> I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for
>>> it, but that'll be fun.
>>>
>>
>> I'm working on a chopper preamp that should be flat down to at least
>> 100mHz, but it seems that I cannot verify that with the 89441A.
>>
>> It works with parallel ADG819 analog switches, step up transformers,
>> more low noise gain with ADA4898s on 500 KHz, synchronous demodulator
>> back to baseband and some more gain.
>>
>> A Xilinx Coolrunner II generates the timing from a 100 MHz osc.
>> It looks like I get 120 pV/rtHz.
>

> I designed a CSEM receiver 20 or so years ago with sub 100pV noise
> (0.01-15Hz BW and 120dB overall gain) with a similar architecture.
> These worked with Ag-AgCl field sensors with a source resistance of
> about 5 ohms.

Just as a reminder, Paul and I made a simple 65 pV/rt-Hz preamp,
all the how-to details reported in AoE III, pages 505 to 508.


--
Thanks,
- Win

[Long Hair]

pcdh...@gmail.com wrote:

> Floor space is a bit of an issue, because we've got a lot of good stuff:
>
> https://electrooptical.net/Lab_Tour/
>
> https://electrooptical.net/Equipment
>
> So I really need a shorter version of the big HP rack in the photos.
>
> Cheers
>
> Phil Hobbs
>

Are you planning on using the rack as a mobile device?

Because they are almost always fitted with small diameter hard casters.

Those Tek carts, BTW can have heavy items fitted right down next to
the floor. It ain't no scope cart. New ones sell for $1500. That is
all we use in our labs. The last one had four in it, right before the
boss moved.

[Phil Hobbs]

On 02/25/2018 11:43 AM, Long Hair wrote:
> pcdh...@gmail.com wrote:
>
>> Floor space is a bit of an issue, because we've got a lot of good stuff:
>>
>> https://electrooptical.net/Lab_Tour/
>>
>> https://electrooptical.net/Equipment
>>
>> So I really need a shorter version of the big HP rack in the photos.

>>
>

> Are you planning on using the rack as a mobile device?
>
> Because they are almost always fitted with small diameter hard casters.

If you look at the big rack, you'll find that it's sitting on a chunk of
butcher block with large cast-iron cylindrical casters with heavy solid
tires from McMaster-Carr. It rolls great. The smaller rack won't need
such beefy wheels.

>
> Those Tek carts, BTW can have heavy items fitted right down next to
> the floor. It ain't no scope cart. New ones sell for $1500. That is
> all we use in our labs. The last one had four in it, right before the
> boss moved.

Carts I can get for cheap, but I really want a rack. Failing all else,
I can get a couple of two-post relay racks and have some cross braces
welded on, but there must be some of the old-timey ones rattling round
out there. Maybe I'll do a road trip to the Dayton Hamfest this year.

[Long Hair]

Phil Hobbs wrote:

> On 02/25/2018 11:43 AM, Long Hair wrote:
>> pcdh...@gmail.com wrote:
>>
>>> Floor space is a bit of an issue, because we've got a lot of good stuff:
>>>
>>> https://electrooptical.net/Lab_Tour/
>>>
>>> https://electrooptical.net/Equipment
>>>
>>> So I really need a shorter version of the big HP rack in the photos.
>
>>>
>>
>> Are you planning on using the rack as a mobile device?
>>
>> Because they are almost always fitted with small diameter hard casters.
>
> If you look at the big rack, you'll find that it's sitting on a chunk of
> butcher block with large cast-iron cylindrical casters with heavy solid
> tires from McMaster-Carr. It rolls great. The smaller rack won't need
> such beefy wheels.
>>
>> Those Tek carts, BTW can have heavy items fitted right down next to
>> the floor. It ain't no scope cart. New ones sell for $1500. That is
>> all we use in our labs. The last one had four in it, right before the
>> boss moved.
>
> Carts I can get for cheap, but I really want a rack. Failing all else,
> I can get a couple of two-post relay racks and have some cross braces
> welded on, but there must be some of the old-timey ones rattling round
> out there. Maybe I'll do a road trip to the Dayton Hamfest this year.
>
> Cheers
>
> Phil Hobbs
>

https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=18+U+rack+enclosure

[George Herold]

On Sunday, February 25, 2018 at 1:35:04 PM UTC-5, Phil Hobbs wrote:
> On 02/25/2018 11:43 AM, Long Hair wrote:
> > pcdh...@gmail.com wrote:
> >
> >> Floor space is a bit of an issue, because we've got a lot of good stuff:
> >>
> >> https://electrooptical.net/Lab_Tour/
> >>
> >> https://electrooptical.net/Equipment
> >>
> >> So I really need a shorter version of the big HP rack in the photos.
>
> >>
> >
> > Are you planning on using the rack as a mobile device?
> >
> > Because they are almost always fitted with small diameter hard casters.
>
> If you look at the big rack, you'll find that it's sitting on a chunk of
> butcher block with large cast-iron cylindrical casters with heavy solid
> tires from McMaster-Carr. It rolls great. The smaller rack won't need
> such beefy wheels.
> >
> > Those Tek carts, BTW can have heavy items fitted right down next to
> > the floor. It ain't no scope cart. New ones sell for $1500. That is
> > all we use in our labs. The last one had four in it, right before the
> > boss moved.
>
> Carts I can get for cheap, but I really want a rack. Failing all else,
> I can get a couple of two-post relay racks and have some cross braces
> welded on, but there must be some of the old-timey ones rattling round
> out there. Maybe I'll do a road trip to the Dayton Hamfest this year.

In grad school my prof found racks expensive, but the wood shop was cheap,
we had wooden racks, 2x4 boxes, with metal cross braces, slots in the
2x4 held plywood shelves.

George H.

[Steve Wilson]

George Herold <ghe...@teachspin.com> wrote:

> In grad school my prof found racks expensive, but the wood shop was
> cheap, we had wooden racks, 2x4 boxes, with metal cross braces, slots in
> the 2x4 held plywood shelves.

> George H.

Plywood takes a permanent sag under weight.

I use metal shelves from Global:

http://www.globalindustrial.ca/g/storage/shelving/Steel-Shelving-Open/steel-
shelving-20-gauge-97-high-open

With 20 ga steel, they can support 200 lb per shelf. That's enough for a HP
8566 plus a stack of signal generators, dmms, vna, etc. or inventory per
shelf. I get the 97" corner struts so I can cut them to whatever height I
need. I put angle iron on the bottom of the legs and drill holes for casters
or rollers to move them around. They are not expensive.

One thing that threw me off at the beginning is they do not itemize orders
when you buy multiple shelves. They simply send whatever shelves and support
struts are necessary to fulfil the order. You have to sort them out yourself
to match the type and number of shelving you ordered. But this is easy once
you figure it out.

Global is a Canadian company. You should be able to find equivalent companies
across the US.

[Phil Hobbs]

On 02/23/2018 02:15 PM, Phil Hobbs wrote:
> On 02/16/2018 09:59 AM, Phil Hobbs wrote:
>> Hi, all,
>>
>> I need another FFT analyzer.  I really like my HP 35660A, but it only
>> goes up to 100 kHz (50 kHz for two-channel measurements).  I'd really
>> like one that goes up to at least 10 MHz, and can do the same sorts of
>> stuff, especially display noise spectral density in different units on
>> different scales and perform frequency response testing easily.
>>
>> There are a bunch of USB-style things, which might be okay as long as
>> they have Linux software available.
>>
>> What I really want is a smallish boat anchor with two channels, 14-16
>> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
>> that can talk to USB sticks.
>
> So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
> that it doesn't have the serial cable--is it a regular straight-through
> 9-pin cable, or something weird?

The beast is currently sitting on my front porch, having been delivered
earlier today. The box weighs over 100 pounds, so I'll have to get DFH
to help move it. Probably nobody is going to steal it in the night.

Film at 11. ;)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

[Jim Thompson]

On Mon, 26 Feb 2018 20:11:11 -0500, Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>On 02/23/2018 02:15 PM, Phil Hobbs wrote:
>> On 02/16/2018 09:59 AM, Phil Hobbs wrote:
>>> Hi, all,
>>>
>>> I need another FFT analyzer.  I really like my HP 35660A, but it only
>>> goes up to 100 kHz (50 kHz for two-channel measurements).  I'd really
>>> like one that goes up to at least 10 MHz, and can do the same sorts of
>>> stuff, especially display noise spectral density in different units on
>>> different scales and perform frequency response testing easily.
>>>
>>> There are a bunch of USB-style things, which might be okay as long as
>>> they have Linux software available.
>>>
>>> What I really want is a smallish boat anchor with two channels, 14-16
>>> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
>>> that can talk to USB sticks.
>>
>> So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
>> that it doesn't have the serial cable--is it a regular straight-through
>> 9-pin cable, or something weird?
>
>The beast is currently sitting on my front porch, having been delivered
>earlier today. The box weighs over 100 pounds, so I'll have to get DFH
>to help move it. Probably nobody is going to steal it in the night.
>
>Film at 11. ;)
>
>Cheers
>
>Phil Hobbs

Sheeesh! I have three different dolly types to cope with such, plus a
block-and-tackle... quite convenient when you're 78 ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

It's what you learn, after you know it all, that counts.

[Jim Thompson]

I did this, at around age 60...

<http://www.analog-innovations.com/SED/BBQ_Project.pdf>

all by my lonesome... the lift-table is quite the nicest tool.

[Phil Hobbs]

I usually get stuff delivered to the house, because there's nearly
always somebody here. I'm generally at the lab during business hours,
but not always. So this beast will be going in DFH's truck tomorrow.

[Phil Hobbs]

The Harvard Over-40 Rowing Club once had some tee shirts made that said,
"The older we get, the better we were." ;)

[George Herold]

Hydraulics... one use and you are spoiled for the rest of your life.
:^) GH

[Jim Thompson]

On Mon, 26 Feb 2018 21:05:27 -0500, Phil Hobbs

Too soon, old... too late, smart. At my age "smart" outfoxes sore or
torn rotator cuffs.

[Jim Thompson]

Yep, Hydraulics are your friend...

<http://www.analog-innovations.com/SED/BBQ_Project.pdf>

[Jeff Liebermann]

On Mon, 26 Feb 2018 21:16:03 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Mon, 26 Feb 2018 18:06:12 -0800 (PST), George Herold
><ghe...@teachspin.com> wrote:
>>Hydraulics... one use and you are spoiled for the rest of your life.
>>:^) GH

>Yep, Hydraulics are your friend...
><http://www.analog-innovations.com/SED/BBQ_Project.pdf>
> ...Jim Thompson

Muscle power is cheaper.

Personal forklift. No test equipment collector should be without one:
<http://4.bp.blogspot.com/_uuOo8x3WXWE/RnvztdIVNpI/AAAAAAAACA0/EBYvrnoag5k/s1600-h/human_forklift.jpg>
<http://www.soceadth.co.jp/index2.html>
<https://www.youtube.com/watch?v=NlLLEdXUEWY> (1:34)

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Phil Hobbs]

On 02/23/2018 03:21 PM, Gerhard Hoffmann wrote:

> Am 23.02.2018 um 20:15 schrieb Phil Hobbs:
>
>> So my new-to-me HP 89441A analyzer is due to be here Tuesday.  I noticed
>> that it doesn't have the serial cable--is it a regular straight-through
>> 9-pin cable, or something weird?
>

> I also had to make the cable myself.
> It wasn't much work, and it is known how to do it.
>
>

Yeah, it's just a straight-through D-9 as it turns out.

I see what you mean by "1/f challenged"--it's about 7 nV/sqrt(Hz) in the
flatband, but 100 nV/sqrt(Hz) at 1 kHz, which is about where it flattens
out. The corner seems to be about 26 kHz, which isn't great.

However, with a decent preamp it'll be a great advance over analogue RF
spectrum analyzers and scope FFTs.

I'm looking forward to trying out that code that you kindly sent me.

[JM]

I like the Zpas SRX open racks, but they not be available in the US.
Having said that, I also thought it would be nice to have a couple of
smaller (24U) racks, but in practice I thought they were just too bulky.
I ended up replacing them with a couple of carts, which seem to be
happy enough with upto three boat anchors, two on the table and one on
the bottom shelf.

https://imgur.com/D6hhXi9.jpg
https://imgur.com/s78dEM8.jpg

[JM]

I think Gerhard is interested in measurements in the 0.1Hz region and
below, where your preamp would be about 26dB noisier than the one he's
working on.

[Castorp]

I've used a number of 89410A devices, and they have exhibited some spread in the noise floor. Usually the flat part is around 8-9 nV/sqrtHz, and the 1/f corner could be in the kHz or tens of kHz. One device had popcorn-like noise in one channel.

With a preamp built of 4 paralleled ADA4522s and LT5400 resistor arrays, I managed to get noise floor of about 5 nV/sqrtHz flat down to a few mHz. If there's interest, I can dig up those measurements. I used it to measure excess 1/f noise in resistors hooked up in a biased Wheatstone bridge, like this:
https://dcc.ligo.org/public/0002/T0900200/001/current_noise.pdf

Another nice trick with the 2-channel FFT is cross-spectrum measurement. With two good preamps and some patience it buys you another 10-20 dB downwards:

https://www.researchgate.net/publication/3622215_Measurement_of_voltage_noise_in_chemical_batteries

Cheers,
Nikolai

[Gerhard Hoffmann]

Am 17.03.2018 um 21:16 schrieb Castorp:
> I've used a number of 89410A devices, and they have exhibited some spread in the noise floor. Usually the flat part is around 8-9 nV/sqrtHz, and the 1/f corner could be in the kHz or tens of kHz. One device had popcorn-like noise in one channel.
>

That would actually be good news, that the noise comes from the input
amplifiers. That would mean that one can use cross correlation on the
two channels. I had some fear that it might be phase noise from the
sampling clock since it is probably synthesized. That would be common
to both channels and would not average away.

> With a preamp built of 4 paralleled ADA4522s and LT5400 resistor arrays, I managed to get noise floor of about 5 nV/sqrtHz flat down to a few mHz. If there's interest, I can dig up those measurements. I used it to measure excess 1/f noise in resistors hooked up in a biased

Yes, especially the setup of the 89410.

Wheatstone bridge, like this:
> https://dcc.ligo.org/public/0002/T0900200/001/current_noise.pdf
>
> Another nice trick with the 2-channel FFT is cross-spectrum measurement. With two good preamps and some patience it buys you another 10-20 dB downwards:
>
> https://www.researchgate.net/publication/3622215_Measurement_of_voltage_noise_in_chemical_batteries

Thanks to plowing with the power of a thousand chicken my setup is only
abt. 10 dB worse than that of Fred Walls, but without cross
correlation. I still can add that.
1000 chicken means averaging over 20 ADA4898 op amps :-).

If you want numbers on batteries that you actually can buy and not some
anonymous thingies that they happened to have in the lab, there is

<
http://www.hoffmann-hochfrequenz.de/downloads/NoiseMeasurementsOnChemicalBatteries.pdf
>

It is still limited by the 1/f of the 89410A and the undersized input
capacitor of the preamp (160 uF foil). I have replaced the foil caps
with wet slug tantal, 4700 u IIRC, but that is only a good decade
better, just a drop in the bucket.

An array of organic polymer electrolytics was too leaky. An array of
wet slug tantals costs too much if I have to pay for it from my own
money. :-(

BTW, two 3.7V Panasonic lithiums are quite OK, noisewise. They seem
hard to top.
<
https://www.flickr.com/photos/137684711@N07/39056813010/in/album-72157662535945536/
>
0 dB is 1nV / rt Hz, DC voltage is 7.3V. The 60 Ohm 1nV/rt Hz reference
resistor and the short switch are on the amplifier side of the coupling
capacitor, so everything looks much better.

The picture of the batteries is to the right.

cheers, Gerhard

[Castorp]

Thanks, Gerhard. You've done quite a lot of good work in this field.

I've always tried to avoid AC-coupling and its associated problems. With near-zero voltages (e.g. balanced bridge), you can survive with some amount of offset, or fix it in between the gain stages. For batteries I've tried (with variable success) to measure two of them back-to-back, in counter-series.

The point of my 4xADA4522 preamp was not to get super low white noise (5 nV/sqrtHz is nothing to brag about), but to have no 1/f. It was all DC-coupled, including the 89410A in its most sensitive range (10 mV I think). With an upper frequency of 1 Hz and 3201 frequency bins (the maximum), it takes one FFT in more than an hour. With overnight averaging it gets smooth enough to make sense.

I'll find those details in the next days, some of them are in my work labbooks.

Cheers,
Nikolai

[Castorp]

So, here's the device with popcorn noise in one of the channels:

http://nbeev.web.cern.ch/device1_psd.png
http://nbeev.web.cern.ch/device1_td.png

The second device is my own 89440 - the only one I have access to right now. Channel A is clearly better in terms of LF noise. The magenta curve is cross-spectrum.

http://nbeev.web.cern.ch/device2_psd_hf.png
http://nbeev.web.cern.ch/device2_psd_lf.png

All these measurements are on the finest range, 1MOhm inputs with external short, DC-coupled.

I coulnd't find the ADA4522-1 preamp measurement files, but I found notes on the setup. The preamp was followed by an SRS amplifier, and the total gain was 10000. That was enough to ensure flat floor down to a few mHz, but around there it did intersect with the 89440A 1/f noise. For my purposes back then it was fine.

All of the batteries I tested showed steeper than 1/f behaviour at low frequencies, so they were not good enough as a DC source for my tests. And I did it carefully - temperature-stabilized oven, no stress, mechanical relief, plenty of time to settle, etc...

Cheers,
Nikolai

[Gerhard Hoffmann]

Hi, Nikolai,
thanks for the information.

I'm just plowing through the 89441A programming manual to upgrade
my control program. The manual leaves of lot of open questions,
the only thing they say again and again is that I cannot use
options that are not built-in.

regards,
Gerhard

[ar...@personalrecharge.com]

On Saturday, 24 February 2018 03:21:07 UTC+7, Gerhard Hoffmann wrote:
> Am 23.02.2018 um 20:15 schrieb Phil Hobbs:
>
> > So my new-to-me HP 89441A analyzer is due to be here Tuesday. I noticed
> > that it doesn't have the serial cable--is it a regular straight-through
> > 9-pin cable, or something weird?
>
> I also had to make the cable myself.
> It wasn't much work, and it is known how to do it.

Hi Gerhard, i have also bought one of these units, 89441A, no serial cable and for the love of peet, i cannot find the cable connection diagram, and standard RS232 didnt work either, could you help out and show me how to do it please?

Thanks!

Arjen.

[Winfield Hill]

ar...@personalrecharge.com wrote...

>
>On 24 February 2018 03:21:07 UTC+7, Gerhard Hoffmann wrote:
>> Am 23.02.2018 um 20:15 schrieb Phil Hobbs:
>>
>>> So my new-to-me HP 89441A analyzer is due to be here Tuesday.
>>> I noticed that it doesn't have the serial cable--is it a
>>> regular straight-through 9-pin cable, or something weird?
>>
>> I also had to make the cable myself.
>> It wasn't much work, and it is known how to do it.
>
> Hi Gerhard, i have also bought one of these units, 89441A,
> no serial cable and for the love of peet, i cannot find the

> cable connection diagram, and standard RS232 didn't work

> either, could you help out and show me how to do it please?

Another question of interest, what's the next, more modern
version of this instrument, one could look for on eBay?


--
Thanks,
- Win

[Castorp]

I made my own cable and it works. It's just a 1:1 connection with DB-9 on both sides, without any crossing of the TX and RX lines. I can double-check tomorrow but I'm almost sure there's nothing else.

Cheers,
Nikolai

[Phil Hobbs]

It's a straight-through D-25 cable.

[Phil Hobbs]

I think the 89441A was the last one with a baseband input.

[Winfield Hill]

Phil Hobbs wrote...

>
> Winfield Hill wrote:
>>
>> Another question of interest, what's the next, more modern
>> version of this instrument, one could look for on eBay?
>
> I think the 89441A was the last one with a baseband input.

What's its floppy drive? A weird HP LIF format?
Can you get the "Standard data format utilities"?


--
Thanks,
- Win

[pcdh...@gmail.com]

>What's its floppy drive?  A weird HP LIF format?

No, it's a DOS DS/DD 1.44 MB unit. You can make decent-looking TIFF plots easily, but (unlike e.g. my TDS 784As) you can't get the measurement data in a plain text file.

Cheers

Phil Hobbs

[ar...@personalrecharge.com]

Hi Nikolai, thanks for your reply! i have tried to wire it true straight, but that did not work, i just connected pin 1 to pin 1, pin 2 to pin 2, ETC. i stopped getting the error at start-up when i omitted pins 1-6-9, but then when i want to measure something requiring the RF section, it gives a communication error. having said that, it seems that the shielding requirements and cable quality requirements could be high, im using two rather Chinese DB9's and un shielded cable

any advice is most welcome!

Thanks so far,

Arjen.

[Gerhard Hoffmann]

Am 23.06.19 um 12:30 schrieb ar...@personalrecharge.com:

I'm currently in southern France, so i cannot check anything. :-)

I use it over LAN only. If the 441A has the network option,
you just open port 50?? on 192.168.178.111 or whatever and then
you can read and write GPIB commands/data from/to it. The network is
old style Ethernet on BNC, so you need a converter box. I had
to terminate both ends of the RG58 cable, even if the cable was only
10 cm long.

I have written a program that runs on Linux, maybe others.
It controls the 441A and does sweeps over seven decades &
creates gnuplot output with dB / log-f axes. That involves
at least 7 different sweeps and it sorts the data together.

This is open source.

cheers, Gerhard

[ar...@personalrecharge.com]

Sounds cool Gerhard! just to make things clear, the serial cable i need to make is for the serial 2 port that connects the RF unit to the main unit. if anyone can let me know how that is wired, then i'd be very happy. i can then use the device up to 2.8GHZ. i was really lucky with this buy, the machine i bought is literally brand new.... not a spec of dust inside, no yellowing, perfect.... :-) i will learn allot with this setup!

[Castorp]

Sorry about the delay, I was suffering from jet lag yesterday (-:

I assumed we were talking about the same thing - the interconnection between the RF and the baseband units.

Here's what I'm using:
https://photos.app.goo.gl/FdixNHhrkBmujr656

The cable itself is short, about 1 m. It's just unshielded ribbon cable. On one side it's crimped, on the other one it's soldered. Nothing special at all, and it works.

Cheers,
Nikolai

[ar...@personalrecharge.com]

Thank you Nicolai, oddly enough, i cannot connect with the RF unit, despite the cable beeing the same as yours. only difference is that i may have reversed it as well, after testing 1 on 1 2 on 2, etc. no results.

the sub-d connectors are quite poor in quality, it may play a role, but im supprised as to why it doesnt work. just to be sure, can you see if its pin 1 on 1, etc? as i cannot see the whole cable on your image.

[Castorp]

I just checked it with a multimeter. It's 1 to 1, 2 to 2... 9 to 9.

I guess you're using the correct port (Serial 2). So I don't know what could be wrong.

Cheers,
Nikolai

[Phil Hobbs]

On 6/23/19 9:14 AM, Phil Hobbs wrote:
> On 6/23/19 7:14 AM, Winfield Hill wrote:
>> ar...@personalrecharge.com wrote...
>>>
>>> On 24 February 2018 03:21:07 UTC+7, Gerhard Hoffmann wrote:
>>>> Am 23.02.2018 um 20:15 schrieb Phil Hobbs:
>>>>
>>>>> So my new-to-me HP 89441A analyzer is due to be here Tuesday.
>>>>> I noticed that it doesn't have the serial cable--is it a
>>>>> regular straight-through 9-pin cable, or something weird?
>>>>
>>>> I also had to make the cable myself.
>>>> It wasn't much work, and it is known how to do it.
>>>
>>> Hi Gerhard, i have also bought one of these units, 89441A,
>>> no serial cable and for the love of peet, i cannot find the
>>> cable connection diagram, and standard RS232 didn't work
>>> either, could you help out and show me how to do it please?
>>
>>   Another question of interest, what's the next, more modern
>>   version of this instrument, one could look for on eBay?
>>
>>
>
> I think the 89441A was the last one with a baseband input.

The E4406 option B7C gives you a baseband input. They're pretty
affordable too.

[Gerhard Hoffmann]

Am 25.06.19 um 11:41 schrieb Castorp:

maybe one of the plugs is in the inverted direction?
It would look 1:1 but it isn't. check the pin NUMBERS.
Gerhard

[ar...@personalrecharge.com]

I'Ve tried it both ways, straight and reversed, both with similar results, odd thing beeing if i connect the cable straight, pin number to pin number and omit pin 1-6-9, i dont get the fault at start up, but i get the fault as soon as the controller unit attempts to communicate with the RF unit. ive seen a serial test protocol in the service manual, i guess that's the next stop, and some nice AMP sub-D connectors would be good also.

Gotta say, you guys have a nice online community here, everyone's very helpful, Thank you all! i really appreciate that!

[Jan Panteltje]

On a sunny day (Tue, 25 Jun 2019 18:45:09 -0700 (PDT)) it happened
ar...@personalrecharge.com wrote in
<c9b0fc07-7bc5-448f...@googlegroups.com>:

To see what the situation is, use a voltmeter on pin 2 and 3 of the things,
the Tx pin should be negative several volts,
and the Rx pin should be around zero volts.
Meaure it on both sides, then you know what Rx and Tx is,
and cross connect those:
Rx to TX on the other sde, and Tx or Rx on the other side.
All other ways are guesswork.

Check baudrate and parity settings.

[Castorp]

I don't think you have any control over the settings and baud rate.

About the pin numbering - I checked that too. They match.

[Jan Panteltje]

On a sunny day (Wed, 26 Jun 2019 00:00:48 -0700 (PDT)) it happened Castorp
<nikol...@gmail.com> wrote in
<d44bba7e-bf77-4edc...@googlegroups.com>:

The same goes for the hardware handshake lines,
it is not often used these days I think, but it is posssible older equipment uses DTR (data terminal ready, output) on pin 4
and DSR (data set ready, input) on pin 6,
same for
RTS (request to send, output) on pin 7,
and CTS (clear to send, input) on pin 8.

And there is also
DCD (data carrier detect, input) on pin 1.

So you cannot connect the cable 1 to 1.

RTS (out) should go to CTS (in),
and CTS (in) to RTS (out).

And DTR (out) shoudl go to DSR (in),
and DSR (in) to DTR(out)

Or this (with 2 and 3 swapped):
https://en.wikipedia.org/wiki/Null_modem#/media/File:D9_Null_Modem_Wiring.png
https://en.wikipedia.org/wiki/Null_modem

So you can loop back too, ig no handshake is needed by connecting CTS to RTS on the same connector, and DTR to DSR, etc.

Hopefully this does not create more confusion ;-)

It is simple actually.

[JM]

On 25/06/2019 12:02, Phil Hobbs wrote:
> On 6/23/19 9:14 AM, Phil Hobbs wrote:
>> On 6/23/19 7:14 AM, Winfield Hill wrote:
>>> ar...@personalrecharge.com wrote...
>>>>
>>>> On 24 February 2018 03:21:07 UTC+7, Gerhard Hoffmann wrote:
>>>>> Am 23.02.2018 um 20:15 schrieb Phil Hobbs:
>>>>>
>>>>>> So my new-to-me HP 89441A analyzer is due to be here Tuesday.
>>>>>> I noticed that it doesn't have the serial cable--is it a
>>>>>> regular straight-through 9-pin cable, or something weird?
>>>>>
>>>>> I also had to make the cable myself.
>>>>> It wasn't much work, and it is known how to do it.
>>>>
>>>> Hi Gerhard, i have also bought one of these units, 89441A,
>>>> no serial cable and for the love of peet, i cannot find the
>>>> cable connection diagram, and standard RS232 didn't work
>>>> either, could you help out and show me how to do it please?
>>>
>>> Another question of interest, what's the next, more modern
>>> version of this instrument, one could look for on eBay?
>>>
>>>
>>
>> I think the 89441A was the last one with a baseband input.
>
>
> The E4406 option B7C gives you a baseband input. They're pretty
> affordable too.
>
> Cheers
>
> Phil Hobbs
>

Just make sure you buy one with the 14 bit IF card...

[pcdh...@gmail.com]

>Just make sure you buy one with the 14 bit IF card...

Care to elaborate?

Cheers

Phil Hobbs

[legg]

If HP could complicate things, it did.

Possibly company policy to ensure customers captivity.

RL

[ar...@personalrecharge.com]

Allright then, did some trouble shooting and found that the power supply of the RF unit had a shorted tantalum capacitor, and no negative voltages present, so i replaced the capacitors, and now it communicates, and the voltages on the power supply seem to be within range. However, now i get a calibration error on the device, so that's the next puzzle to solve.

[Castorp]

Good job!
Do you have Source connected to IN on the RF unit with a short BNC-BNC cable?

[JM]

Well, I don't suppose it'll affect working at baseband since these cards
have their own ADC's, but for working at higher frequencies the 14 bit
IF card is worth having. Last time I was looking for an E4406 on ebay
none of the dozen or so units had the 14 bit IF card.

FYI these are the serial numbers to look out for:-

Serial number beginning MY (made in Malaysia), or US41513009 or greater.

Alternatively, a serial number on this list: US4136 prefix, with suffix
2964, 2977, 2982, 2986, 2987, 2988, 2989, 2990, 2991, 2992, 2993, 2998,
3000, 3003, 3004, 3005, 3006, or 3007.

[jjhu...@gmail.com]

On Friday, February 16, 2018 at 9:59:38 AM UTC-5, Phil Hobbs wrote:
> Hi, all,
>
> I need another FFT analyzer. I really like my HP 35660A, but it only
> goes up to 100 kHz (50 kHz for two-channel measurements). I'd really
> like one that goes up to at least 10 MHz, and can do the same sorts of
> stuff, especially display noise spectral density in different units on
> different scales and perform frequency response testing easily.
>
> There are a bunch of USB-style things, which might be okay as long as
> they have Linux software available.
>
> What I really want is a smallish boat anchor with two channels, 14-16
> bit resolution, > 50 MS/s sampling, FFT analysis, a nice display, and
> that can talk to USB sticks.
>
> Any faves?
>
> Thanks

>
> Phil Hobbs
>
> --
> Dr Philip C D Hobbs
> Principal Consultant
> ElectroOptical Innovations LLC / Hobbs ElectroOptics
> Optics, Electro-optics, Photonics, Analog Electronics
> Briarcliff Manor NY 10510
>
> http://electrooptical.net
> http://hobbs-eo.com

I have this scope on my bench and I like the FFT function. Off the top of my head, I think it meets your specs...( my scope is fully loaded with all the math packs)
https://www.keysight.com/en/pdx-x201899-pn-MSOX3104A/mixed-signal-oscilloscope-1-ghz-4-analog-plus-16-digital-channels?nid=-32540.1150227&cc=US&lc=eng
They have been in the market for 4-5 years now so you might be able to pick up a used one at 1/2 price...

[pcdh...@gmail.com]

>I have this scope on my bench and I like the FFT function.  Off the
>top of my head, I think it meets your specs..

Scopes are almost always 8 bits, which limits their FFTs to about 50 dB dynamic range. (I have four scopes that do FFTs.)

The HP 89410A suits me very well apart from the 1/f noise.

Cheers

Phil Hobbs

[Winfield Hill]

pcdh...@gmail.com wrote...

>
> The HP 89410A suits me very well apart from the 1/f noise.

It's big and bulky, and awkward. HP made elegant portable
FFT-based audio analyzers, to 50 or 100kHz, in the old days.
Why can't somebody make similar now, but to 5 or 10MHz?


--
Thanks,
- Win

[Phil Hobbs]

On 7/4/19 2:29 PM, Winfield Hill wrote:
> pcdh...@gmail.com wrote...
>>
>> The HP 89410A suits me very well apart from the 1/f noise.
>
> It's big and bulky, and awkward.

Well, so am I, except for awkward. I have this nice 7-foot HP rack to
put boat anchors in. I pay about three cents on the dollar for
top-of-the-line instruments, which suits me very well.

Of course in my line of work, I get to keep the money I don't spend. ;)

Cheers