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Good news! I'm glad it worked and I could help.

73!
Razvan

Ed: The Leo B GPS (and most GPS/TCXO etc) have Zo 50 Ohms.
We have a stock of vintage BNC 2X, 4X, 6X 50 Ohm wideband splitters.
These are used often for video , so perfect BW for 5..10 MHz.
Running the GPS at max output, the losses in the splitters (use transformers) still give > 500 Mv at the loads.

Our setup: Leo B 10 MHz>>Mini Circuits 2X>>Mini Circuits 4X, 6x etc.
We drive 6 to 10 devices: Counters, spec/network analyzers, scopes.

Min-Circuits are good cost/availablilty.


Jon

Apologies? typo error:
Not 70902,
.... should read 70900a > 70900b

Hi Razvan

thank you, it worked OK.

I tried it first with a 2GB compact flash card but that didn't work so I tried a 256MB card and it worked OK so presumably it does not recognise such a large card.

Thanks again.

regards
Charles Edmonds VK3CLE
Mob: 0418309921
charles.edmonds@...

hi Ron.

For additional info:

See:
the Hp70k thread on the eevBlog:

I assume that you distribute the reference through a resistive splitter to each device.
The output of the LEO is a square wave and long cable lengths can cause waveform distortion due to reflections, especially for those units tapped off along the line.

ed

Hello Charles,

I uploaded the last firmware released which was A06.25 and also the
Measurement Guide and Service Guide manuals.

/g/HP-Agilent-Keysight-equipment/files/All%20HP,%20Agilent%20and%20Keysight%20instruments%20in%20folders%20by%20part%20numbers/7000%20to%207999/E7495A_B

Firmware is the same for both A/B versions.

Regards,
Razvan

Hi,

I have an E7495A with F/W A.03.10-0.0.0.0. I can't find anything more recent on the Keysight web site or anywhere else. I particularly want to get at least A.03.20 as that adds a Sample Marker so should be better for measuring noise levels.

Hoping someone can help please.

regards
Charles Edmonds
(Melbourne, Australia)??

We used the excellent Leo Bodnar GPS for years,



USB and Windows interface allow selection of F and V, 800 hZ..800 MHz, out to 32 dbm

We set the F to 10.000 MHz and output to MAX.

We distribute the ref to all our TEK/HP/other via Mini circuits splitters, one Leo B GPS drives 5..10 50 Ohm ref inputs.

Enjoy

Jon

Hi there!

I'm not a time nut, but almost. I like my equipment to go at the same rythm, so I spent about €200 on two boxes: a GPSDO and an 8-output distribution amplifier and I am very happy with the result. My frequency measurements are precise and synchronized enough. Those were bought at eBay, from China, you know, that green and aluminum small boxes.

Regards,
Ruben

The following files and folders have been uploaded to the Files area of the [email protected] group.

• /Winchester-Rack-and-Panel-Brochure.pdf

By: RubenRubio <rubenrb2019@...>

Description:
Cataloge for Winchester Electronics Connectors present in 8660 synthesizer system mainframe and plugins

On June 19, 2024 10:10:57 PM "Dave McGuire" <mcguire@...> wrote:

On June 19, 2024 9:59:33 PM "Roy Thistle" <roy.thistle@...> wrote:

Time Nut

'time nut' ... 'volt nut'... or 'audiophile'... IMO... they sometimes make it harder for other 'nuts' to get the resources they need to actually 'do' stuff.

The difference bei6, of course, that the former two actually know something about technology.

(err, "being")

--
Dave McGuire, AK4HZ
New Kensington, PA

On June 19, 2024 9:59:33 PM "Roy Thistle" <roy.thistle@...> wrote:

Time Nut

'time nut' ... 'volt nut'... or 'audiophile'... IMO... they sometimes make it harder for other 'nuts' to get the resources they need to actually 'do' stuff.

The difference bei6, of course, that the former two actually know something about technology.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

On Wed, Jun 19, 2024 at 09:03 AM, Matt Harris wrote:

Time Nut

'time nut' ... 'volt nut'... or 'audiophile'... IMO... they sometimes make it harder for other 'nuts' to get the resources they need to actually 'do' stuff.

On Wed, Jun 19, 2024 at 06:08 PM, Jim Ford wrote:

Cheap way to get atomic clock stability

AFAIK, Cesium atomic clocks are the most accurate timekeepers... 100 to 1000 times better than a GPSDO, with a rubidium oscillator.
Anyway, a rubidium oscillator, or OCXO, will drift as it ages... beyond the capability of the GPS system to correct that... if I understand it correctlly?

On Tue, Jun 18, 2024 at 01:19 PM, jmr wrote:

I just don't see much advantage to having a common frequency reference.

If it really is a reference, and not a 'reference' then it will help eliminate systemic measurement errors, but, the combination of the reference, and the synced instrument, will always increases uncertainty...? due to random errors in the synced instrument. However you can use statistics to reduce the random errors. Statistics can't reduce systemic errors.

I second that about spur tests taking large amounts of time.? We have several test benches at work and each one has a daisy chain for the 10 MHz reference, one instrument used as the source output, and the others are inputs.? We do sometimes see Reference Unlocked error messages on some of the instruments, though.? It's surprisingly easy to get suckouts at 10 MHz on the line.? Video equipment has switchable 75 ohm terminations, so that only the piece at the far end from the source has the termination connected to the line.? IDK why the test equipment manufacturers don't do the same with the 50 ohm internal terminations.? My garage lab has a distribution amplifier between the GPSDO and the instruments, each instrument with a dedicated RG-58 cable to it.? I'm not going for those suckouts.? The Leo Bodnar GPSDO cost me about $150, and the DA was less than $100.? Cheap way to get atomic clock stability.? ? HTH.? ? ? ? ? ?Jim Ford?

Ok ??the 70900 A? in original configuration can only support a selection of the 70000 modules

The same goes for the 70900 B? the key hear is the software / farm ware level

As a lot of 70900 A have been upgrades with faster memory / later firmware
you can have the case that a 70900 that has an A on the front panel actually supports more modules than an early B unit

Luckily there is a full list of firmware and what units that revision of farm will supports

?

The manual is located hear ?suggest you look at Pg 70 and? Pg 71 as this is a synopsis of all the firmware levels used by the 70900

?

/g/hp70000/files/70000%20MMS%20Catalog%27s/HP%2070000_MMS_Catalog%20191%20pg%20including%204%20missing%20pages.pdf

?

You will find that printing this manual out and binding it will be a great benefit in the long run to help in configuring HP 70000 systems

?

Regarding servicing the? 70900 the service manual and most of the CLIP¡¯s are available

Depending on the fault but a starter is to replace all the tantalum capacitors in the 70900 power supply with new TOP quality ones suggest Vishay

?

Regards Paul

Hi J:

Some decades ago I wanted to measure mixer spurs in an automated test system and speed was very important since a lot of spur frequencies needed to be checked.
In order to see low power levels the resolution bandwidth needed to be narrow.? That means the spectrum analyzer needs to tune to the exact frequency of the spur.? A couple of synthesizers supplied the LO and RF inputs to the mixer.? All that was needed to get this to work was to connect the 10 MHz reference output from the instrument with the highest quality internal reference to the Reference Input of the other instruments in a daisy chain.

--
Have Fun,

Brooke Clarke

axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.

See also the firmware compatibility service note, attached.