On Wed, Mar 20, 2019 at 10:06 PM, Tim Tuck wrote:

Next comes Wiltron synthesizers 67xx. The one I have been looking for is 6759B which is 10MH - 26.5GH synthesized with very good specs. very close to 8673B actually
their service manual is also available. 6769 goes up to 40GHz

They look nice, but I don't know anything about them - I've kept with HP for 99% of my lab because its reliable and I can service them but if there's reasonable documentation, parts etc. for those, I may consider it.

and finally Gigatronics 1026 and 7100 and 7200. they all synthesize the frequency and have very good specs but not sure about service manual availability,_._,_

Yeah... and that's the thing isn't it. I see no point expending $ on kit if there's no support.

Right, I'm finding this out with the Wavetek Pacific Measurements 1038-NS20 and NS201.? I'm still wondering about an Operation and Maintenance Manual with schematics for the N10. (Note the N10 & N20 aren't the signal source).?

I still haven't figured out exactly if the PM 1038 can handle up to 26GHz and if so... which modules.? Reads there are sensors/detectors that do rate up to 26GHz.?

G'Day,


On 21/03/2019 1:56 pm, amirb wrote:

I have also been in the market for a 26GHz SG for a while with no luck. Although I have to say the biggest issue for me
has been the sellers not shipping to Canada. I came close to getting a 8673B for $150 but then the seller finally decided he wouldn't ship to Canada...

Yep - I hear ya. At least it can be road freight from the US to you, I'm on a bloody big island!

with regard to models:
8673B (has modulations) and 8673G (strip down version of B with no modulation) go from 2GHz-26.5GHz and at least for my purpose they are fine
both have excellent specs and they are synthesized signal generators. 8673D is also an option (0.05G-26.5G) but it is huge like a tank

I missed out on a 8673G for $800 just recently :( - I do like those units since they can drive the millimeter-wave sources, and ... at some point... I'd be looking to get one or two of those two since I'm slowly working through the SHF bands building transverters and I intend to end up on 122Ghz at some point.

I only need something to go from 3Ghz up since I have an ESG4432b to cover from 3Ghz down as well as a couple of other gens for down to a uHz.

the best overall in my opinion is 8340B or 8340A (no FM modulation) they go down to 10MHz and up to 26.5GHz with excellent
specs on accuracy and noise and they are standard calibration sig gens for spectrum analyzers.

Yes they are nice ! -? I have a saved search for them too.

remember 8350B is a sweep generator and the oscillator modules that come with it are NOT synthesized sig gens. they are generally poor on stability and accuracy
and that's why they have a low frequency resolution, too, I guess but their amplitude is stabilized in an ALC loop
I wouldn't go down that path unless you are in a hurry for a particular project

I'm in no hurry and they would be a last resort, one of my associates has one and a few plugins and a bunch of external attenuators, but its all too much kit and I only have a little lab that already has too many things in it, so what ever I get something has to leave to make room.

Next comes Wiltron synthesizers 67xx. The one I have been looking for is 6759B which is 10MH - 26.5GH synthesized with very good specs. very close to 8673B actually
their service manual is also available. 6769 goes up to 40GHz

They look nice, but I don't know anything about them - I've kept with HP for 99% of my lab because its reliable and I can service them but if there's reasonable documentation, parts etc. for those, I may consider it.

and finally Gigatronics 1026 and 7100 and 7200. they all synthesize the frequency and have very good specs but not sure about service manual availability,_._,_

Yeah... and that's the thing isn't it. I see no point expending $ on kit if there's no support.

Thanks for the pointers, I'll do some research.

regards

Tim

Glen,

Thanks for the previous two messages.

Good progress: The machine boots right into XP without problems. Needed to work around passwords on the unit, but that was easy enough using chntpw.

Self-tests pass on all modules, except for those that I believe require external hardware or configuration to pass.

The fitted 80GB IDE drive has only about 10GB in use. It's amazing what used to get us by. I ordered a SIL3114-based PCI-SATA card -- the best I can tell this should be supported natively. The USB ports are only USB 1.1 on the unit, which rules out using flash drives for anything "serious." I hope that gigabit ethernet will be faster!

Also ordered a cheap SSD which should perform at least better and more reliably than an old rusty spinner.

Keysight support has been great, and provided both BIOS update disc which I caught wind of, and a factory reset OS disk image. I haven't tried these yet, but will soon to at least ensure their integrity.

There are MacroVision lmtools .lic files in the Program Files directory. I think they get "applied" to the modules which I believe writes an EEPROM or some NVRAM on the module itself. According to support, no files need copied/persisted in order to maintain the options....They call the .lic files "Entitlement Certificates" which get emailed. They are small ~152 byte files.

Thanks,
Keith

On Tue, Mar 19, 2019 at 07:22 PM, Joe / KN5U wrote:

By the way, the original fan was 120 VAC, but repair note changed the fan to 24 VDC. This was precipitated by the power supply relay and socket overheating. The repair note had a description of a circuit mod using a diode and also replacing the fan and socket. I have done a few of these mods and this a fairly simple fix. Let me know if you need a copy of the change.

Joe, KN5U

The fan on my HP5335A is 24V, so I guess the modification you mention has already been applied.

On Tue, Mar 19, 2019 at 07:17 PM, Joe / KN5U wrote:

Dan,

This is a great question. My experience is that the critical parts for cooling consideration are the input amplifier U3 and U4 (Schmitt amplifier). These are highly susceptible to shortened life due to heating. Of the 200+ units I have refurbished, interestingly, those that had underpowered fan replacements also had one or both Schmitt amplifier chips not working. So my suggestion is to replace the fan with one of the proper air flow. Especially considering that the Schmitt amplifiers are no longer available.

Regards,

Joe, KN5U

Thanks Joe. I will look for another fan with better airflow characteristics. Of course, I could always go for a Papst fan with better noise characteristics.

On Tue, Mar 19, 2019 at 08:04 AM, Alex wrote:

BTW wanted to direct your attention to that black resistor towards the front of the board and just to the right of one of the red relays next to the lithium battery, that I assume might be related to the Amps readings (which I have not tested yet). Is this the normal appearance for this part? I really does not look too abnormal, but it seems like it has a tiny bit of some brown-reddish stuff on the sides where the wires meet the body of this resistor. I just put up a more detailed picture in the gallery as well. Thanks!

Jeff,
That is the 0.1 Ohm wire wound current sensing resistor.? It looks kind of ratty because of the coating but that is normal.? The reddish-brown stuff I do not know -- could be oxidation from flux.

The negative readings seem suspiciously like thermal voltages from all the contacts you are making in shorting the input.? The best way to apply a "short" is to NOT use these fancy "gold plated" speaker lug/clips.? ?Make you own banana plug SHORT out of soft copper tubing --? type " L" and just bend the tube into a "U" so you have no solder connections or other interfaces other than the tube connecting with the input banana jacks -- two contacts? Hi and Lo.? Choose about 2.5" overall length to start with.?

Another way to make a very good SHORT is to use? AWG #6 solid copper wire - again start with about 2.75" overall length.? The input jacks have an inside diameter of about 3.8mm and #6 AWG solid wire has a OD diameter of??

AWG 6

OD dia? 0.1620 in

OD dia? 4.115 mm

?

?

?

? ? ? ? ?micoOhms? ? per inch? ? ? ? 32.93? ? ? ? ??

milliOhms per foot 0.3951

milliOhms per meter: 1.296

You can whittle down the diameter of the #6 wire to fit the input jacks of the 3468/3478 multimeter by putting the ends of the wire in the jaws of a pair of adjustable lock pliers that has gripping grooves in the jaws and rotating the wire to shave the diameter a bit.? Then bend the wire into a "U" with proper spacing between the ends.

This wire short will be good to 66 microOhms as measured on my Hp3458A using offset compensated Ohms which nulls out the thermal offset voltages?(1 count on the low Ohms range =? 10 microOhms).? Length of wire short when inserted in the meter is about 2"? so the inherent resistance of the short = ?2" x 33 microOhm/inch? =? 66 microOhm as measured on the HP3458A

If you make two such shorts for the INPUT and SENSE input jacks and jumper a wire between them for 4-wire Ohms, this type of short is almost as good as the massive thermal block short I have for calibrating meters.??The difference is in thermal voltages generated and thermal stability of the short which is only a difference of 1 count?on the Hp3458A (10 microOhms).

Now if you calibrate the Ohms ranges in 4-wire ohms and switch to 2-wire Ohms, it is not unreasonable for the meter to display as much as 0.5 Ohm with the short applied due to the current from the Ohms converter passing thru trace resistances, wiring to the input terminals and the return ground circuit to the reference ground of U101 along with?thermal voltage offsets generated internal to the meter between the meter input and the input to the DCV amplifier U101.? Shorting the meter inputs with a short in 2-wire Ohms is meaningless if the meter was caled in 4-wire Ohms.? Doing such can give you all sorts of strange readings positive and negative which depends on the nature of thermal voltages? and contact resistances generated by attaching test leads to the meter.

If you are going to ZERO cal in 2-wire Ohms, it makes no sense to do so with a short applied to the meter input between Hi and Lo for the current from the Ohms converter passes from the Hi terminal to the outside world and will produce a voltage drop along your test leads which will register as an offset equal to the resistance of your test leads and after calibrating will be added to the resistance you are trying to measure.? To ZERO cal the meter in 2-wire Ohms, do so with your test leads attached and shorted at the probe tips of the test leads and not at the meter input.? Then use the test leads you caled with for making your measurements in 2-wire Ohms.? This will give you the most accurate readings.

Good metering to you all and happy equinox.

George? ? March 20, 2019? 10:50pm

Hi Peter,

The main and FM coil signals pass through the A3 ALC board like this:





The FM -? tap to the cavity oscillator is not part of the basic phase lock scheme, it's a spur avoidance fix. You don't need to waste time on studying that unless the fault is there.

Since you mentioned that the YTO is off (high?) by 200MHz, I think you should look at the main coil driver. It seems like something is preventing the main coil driver from delivering a low current. I am not aware of a PLL switch point at 1 GHz, but I have forgotten a lot about it so I may be wrong.

Vladan

I have also been in the market for a 26GHz SG for a while with no luck. Although I have to say the biggest issue for me
has been the sellers not shipping to Canada. I came close to getting a 8673B for $150 but then the seller finally decided he wouldn't ship to Canada...

with regard to models:
8673B (has modulations) and 8673G (strip down version of B with no modulation) go from 2GHz-26.5GHz and at least for my purpose they are fine
both have excellent specs and they are synthesized signal generators. 8673D is also an option (0.05G-26.5G) but it is huge like a tank

the best overall in my opinion is 8340B or 8340A (no FM modulation) they go down to 10MHz and up to 26.5GHz with excellent
specs on accuracy and noise and they are standard calibration sig gens for spectrum analyzers.

remember 8350B is a sweep generator and the oscillator modules that come with it are NOT synthesized sig gens. they are generally poor on stability and accuracy
and that's why they have a low frequency resolution, too, I guess but their amplitude is stabilized in an ALC loop
I wouldn't go down that path unless you are in a hurry for a particular project

Next comes Wiltron synthesizers 67xx. The one I have been looking for is 6759B which is 10MH - 26.5GH synthesized with very good specs. very close to 8673B actually
their service manual is also available. 6769 goes up to 40GHz

and finally Gigatronics 1026 and 7100 and 7200. they all synthesize the frequency and have very good specs but not sure about service manual availability

Use SP 1.3, since you have a more or less fixed IF frequency. Page 3-128 in
the 8970S manual is pretty clear about that. Also be sure to use SP 3.0,
which sets the IF frequency. Since you probably aren't doing a swept NF
measurement, ignore that part of the procedure. Since the output of the
noise source is within range of your 144 MHz input, and the IF at 30 MHz is
within the range of the 8970B, you can set this up just like doing a preamp,
except that mode 1.3 allows you to tell the system to use the ENR of the
noise source at 144 MHz, while listening at 30 MHz. During CAL, the 8970B
listens at 144 to get the source power levels, then during measurements,
listens at 30 MHz.

You might try, as an experiment, just using the 8970B in its SP 1.0 mode.
The input an output are not far apart and the source is pretty flat, as is
the receiver in the 8970B. You might find you get an almost identical result
to SP 1.3.

Yeah, the manual can be aggravating at times; it can take a lot of digging
to find what you need to know.

Hang in there, you'll get it working.

Tom Holmes, N8ZM

On Mon, Mar 18, 2019 at 07:41 PM, Colby Burkett wrote:

Sean, I have a lot of parts for the 8664/8665 series sig gens. Let me know what you need and I'll see if I have it.

?

Colby

Would you happen to have the bit of hardline coax that connects the front panel RF out to the inside? I'm worried that might have been damaged.

Sean

On Wed, Mar 20, 2019 at 05:38 PM, Colby Burkett wrote:

Agreed on the Bird reference. They're great inline watt meters for high power needs, but not for fine performance verification. I use the E4418B and E4419B w/8482A and E9300A heads, or a U2001H USB Power Meter - depending on where I am....

?

Colby

Thanks as well...good stuff to start watching for.

Sean

On Wed, Mar 20, 2019 at 05:28 PM, Bob Albert wrote:

For a decent power meter you do NOT want a Bird.? They are pretty sloppy.

?

I use my HP410B for example.? I calibrate it with my HP 3456A in the audio range and then it's good up to at least 500 MHz.? My HP 8657B isn't all that accurate and I have to use the Offset to get more accurate readings.? The spectrum analyzers are, as you say, not too accurate.

?

On the other hand, I don't need precision amplitude.? All I do is calibrate S meters and you can barely see 1 dB on them, and most aren't too accurate over the range.? So as long as I have 50 microvolts I am happy.? Flatness is another issue but then the SA does a good job.

?

Bob

?

On Wednesday, March 20, 2019, 3:43:53 PM PDT, <[email protected]> wrote:

?

?

On Wed, Mar 20, 2019 at 03:03 PM, alwyn.seeds1 wrote:

Dear All,

?

Measuring signal generator output accuracy with a spectrum analyser, even as nice a one as the 8566B, does not make a lot of sense since the amplitude accuracy is limited. The 8566B flatness is +/- 2.2 dB to which has to be added the calibrator accuracy of +/- 0.3 dB. A good signal generator has much better accuracy.?

?

What you need for the job is a decent RF power meter, which will give you a total measurement uncertainty of about +/- 0.4 dB.

?

Regards,

?

Alwyn ?

Hi,

I am looking into getting one. The purpose of the above exercise is simply to make sure there are no gross problems with the 8664. Of that I am quite sure now, so I am keeping the instrument and getting a bit of a refund from the seller.

Sean

Thanks for the pointers on power meters. Needed one eventually anyway (isn't that the best excuse for buying more test gear!)

Sean

I'm having a little difficulty fully understanding the YTO frequency control loop.

There is a pretune DAC which gets the Main Coil to the right general vicinity.? The fine tuning (including sweeping when in each sub band) must be via the FM coil on the YTO I presume?? I see there is an FM driver-looking output on the phase lock board, does this go directly to the YTO as well?? What part do the circuits on the source assembly play in this?

I'm trying to understand how the loop is closed and the exact mechanism of control of the YTO.

Peter

Hi Don,

Thanks for the info. I went to hparchive.com and downloaded a catalog or two and they gave me what I'm looking for :)

thanks

Tim

I like the "attack" concept (!), however, that's the crux of my question - can I gracefully disassemble the problem end (agree I should be able determine which), or should I cut away the boot and try to figure it out? I'm trying avoid re-invent the wheel (and improve odds I don't just destroy the cable trying to disassemble it.)

Thanks!

Also check the HP memory site, I may have seen some comparison guides to
there, there will not be comparisons to anything Agilent and later though.
Don Bitters

--

Over the years there have been several HP/Agilent/Keysight sig gen/ sweep gen comparison/purchase guides, generally in the sales literature. I have also seen comparison guides between Fluke and HP/Agilent and Rhode & Schwartz RF sig gens and sweepers. I did a little searching for RF comparison guides and found the Keysight one as you noted. Most of the others I found were simplified catalogs for other companies like Rigol and Stanford Research. There are a couple of others like Global Spec and Engineering 360 that listed multiple companies products and a comparison. There was also a comparison guide for RF generators <$100. I did not find any of the HP/Agilent/Keysight comparison guides I have collected over the years. I believe I still have them, but they are in filing cabinets in one of my storage units. Some are lengthy- 40+ pages. When I find them I will talk to Dave @ Artek Media about scanning them and posting them either to this forum or on his site. Nothing I have is more current than 7 years ago, but probably goes back to the early 80’s.
Best regards,
Don Bitters

开云体育

Hi James,

That model is a candidate _BUT_ they don't ship internationally and that makes it harder to get. The freight can be enormous on these units too, so finding one at-the-right-price and with reasonable freight can take time.

regards

Tim

On Wed, Mar 20, 2019 at 01:35 PM, Tim Tuck wrote:

I was wondering if there is a sig gen comparison chart somewhere.

I'm wondering the same and will probably start putting one together like I did with the SDR's and some other components once I get to working on.? Seems over the years there would be datasheets or sales instruments (docs/webpages) that would have some range of comparison that can be combined.

I'm awaiting shipment of some Pacific Measurement 1038 systems and some working components to test the Wavetek NS201 with.?

I was just looking yesterday at this system on eBay that seems like a descent price:?

Thanks in advance for your time and any feedback.??

James