Wiltron 560A help (scalor network analyzer) - diyAudio
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Old 13th May 2010, 10:34 PM   #1
anatech is offline anatech  Canada
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Default Wiltron 560A help (scalor network analyzer)

This is split from the "distortion analyzer" thread.

Quote:
Anyone have some leads for a Wiltron 360A Scalor Network Analyzer? I got one of these (low freq option) that I'm trying to repair. Of course, no probes came with and I can't find any. I suspect an HP 8510 may possibly use similar probes. I don't know if I can fix the thing yet, so I'm not into spending a ton trying to find out.

Now, if anyone has a 3577A or similar they want to get rid of .... Didn't think so, not surprising.
This is an excerpt from my post in that thread.

-Chris

Excerpt from Demian's post in response to a comment from me. The entire post exists in the "Distortion Analyzer" thread.

Quote:
The Wiltron 360A is a vector analyzer, which means no probes in the sense you are mentioning. It has two RF receiver channels that are operated in sync/phae locked to it can measure the phase difference. The inputs will probably fry with more that a volt or two. Here is the link for info: Vector Network Analyzer - 360 - Anritsu This is a realm where everything is really expensive. The test cables for it could easily run $2,000. Some idiot fried one input to the Agilent 8753 VNA and the part from Agilent was $2,000 plus $900 to recalibrate it. We found a spare on fleabay for $500 and got it working OK.

Do you have the whole instrument with the S Parameter test set? I believe it has the source internal but I'm not sure. This page seems to have all the manuals for download: Anritsu 360 - 40 MHz to 26.5GHz Coaxial Vector Network Analyzer (888-683-2872) (National Test Equipment, Inc.) It seems to have millimeter wave capability. LF may mean 10 MHz.
Hi Demian,
Thank you for responding to my very O.T. post.

The null meter is still valid. Your leakage will be chassis to earth, so a floating null indicator should probably be used. That would eliminate any leakage issues, working on a nylon cutting board will help, or a sheet of Teflon if you can get it to borrow.

Quote:
The inputs will probably fry with more that a volt or two.
Yes. Someone did tell me they used a diode detector. I found an article on building these (good ones, not a diode on a wire!) which I may attempt. The jacks do supply power to the probe (they are probes, sadly). I also picked up a vector voltmeter, an HP 8405A. Those have permanent probes and one looks rough on mine. I have yet to power it up though. Maximum input on that instrument is 2 V pk. Huge for what it's used for. I've been doing a lot of FM IF work and I need to be able to sort out front end issues as well. So that's the planned use. Some day I'll get a proper RF spectrum Analyzer as well.

The Wiltron has a range up to 1.3 GHz, from 1 MHz I think. It's the lowest top end in the lineup, but fine for a starter unit for me. I have some GPS antenna work I'd like to do, as well as some 10 MHz distribution stuff to put together. The HP 5087A I picked up is loaded with the wrong amplifiers, all 5 MHz and 100 KHz. So a manual for that is needed. I haven't seen one for download yet, so it's a waiting game. I will eventually be building the new circuits they designed at NIST (great site!).

I am hoping to use an HP 8656B as a source (nothing built in), and no, no S parameter set for it. That's an option I will need for a used VNA some day. Yes, everything in this range is silly expensive, and it doesn't come down in price over time either it seems.

Being silly: I think for audio work, one for my 3585A would work. Running audio transistors and modules up to 40 MHz should suffice.

Thank you for the links. That's where I'll be now.

-Chris
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Last edited by anatech; 14th May 2010 at 03:31 AM. Reason: making a mess moving posts about quite randomly
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Old 13th May 2010, 11:06 PM   #2
1audio is online now 1audio  United States
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You have a 560A, not a 360A most likely. Very different and 25 years difference. It doesn't have a source if its a 560A so you will need a sweeper that covers the range of interest. The probes are diode detectors using shottky or germanium diodes and usually have a thermistor temp compensation. You can get detectors good to 50 GHz for that unit.

For the antenna project you need a return loss bridge. As we go OT into another parallel universe- you can buy good GPS antennas for less that these components will cost and building a "choke ring" GPS antenna is quite the project (a pie pan with a cheap magnetic gps antenna will go a fair way for stationary applications for peanuts). For a 10 GHz dist amp you can experiment and possibly the LME49713 could be a real winner BUT the best ones have carefully tuned input and output networks, which you need the return loss bridge for: Wiltron, SWR Bridge, Model 60A50 - eBay (item 200286837819 end time Jun-03-10 09:21:50 PDT) or you just shop around. I have a DA with a bunch of extra modules for 10 MHz (I think) that I'm not using. Let me know if its interesting and I'll get back to you with details.

The 8405 uses sampling techniques and the probes are not trivial to fix. After using a modern VNA is hard to go back to the older solutions for things like IF's and RF amps. The Wiltron with a sweeper (an FM test generator would be fine) and some diode probes (you don't need the thermistor correction to get useful data) would get you checking SAW filters fast. I could characterize a few for you at some point on the Agilent to use as references.
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Old 14th May 2010, 03:07 AM   #3
anatech is offline anatech  Canada
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Hi Demian,
Of course, you are exactly right on that. It is indeed a 560A, or 5609 specifying the lower frequency model. That should do me just fine in the shorter term - if I can get a signal into it. So much for trusting my memory on that.

I used to have a Wavetek 3001 that I know would have worked as a source. Sent it in to a calibration shop for an estimate and possible cal a couple years ago. It went in with my Philips PM3070 'scope. After almost a year, I got the 'scope back - destroyed. The 3001 hasn't been seen since either. A fellow I know at Electro Rent Corp. had recommended that shop to me, so I let him know what happened (not that it helps me at all). I was able to buy most of the parts for the front panel (wrong colour) from Fluke and I managed to get it working. The calibration that was so carefully done a few years ago was greatly disturbed, even the DC balance is out to lunch. I don't have the equipment available to align it again and the basic cost at Fluke is $900 + . Ripoff if you ask me.

I can't believe so much damage could happen to equipment in a calibration facility! They didn't even have a reason to adjust anything (it was in for a report on visual fluid marks. The 'scope worked otherwise). Need a 'scope some day in the future.

I don't know if I can use the 8656B as the swept source, I'll have to check. Odds are that they may simply not talk to each other. Otherwise I'll need to pick up a generator later on. Getting the matching Wiltron might be the easiest way for me. I do expect to have to service it.

The detectors are my primary concern right now. I have the 560 creating reasonable traces with no signal, and lot's of noise from some switches. At least I know it mostly works. I'll worry about a generator after that. Personally, I really wish I could get an HP Spectrum Analyzer that covers the ranges I need. That would be more simple with fewer boxes in the rack.

The antenna project will be one heck of a learning experience for me. I have very little knowledge of things RF, unless I'm trying to get rid of it. I currently do have a Trimble unit that is working, but the antenna I got with it looks like its meant to sit on a dash or something. The satellites can be locked, but there are gaps during the day and low signal strength to begin with. No surprises here. The Trimble is on my bench in the basement while the antenna sits directly above me, two floors up. I had run RG-6 when the house was built, so the cable runs straight up with no bends. Lucky there. I have an idea to run the cable out the wall and mount a stationary antenna out there (southern exposure). The existing antenna is clearly made for indoor use only. If I can buy a proper antenna, I will. I just have no idea where to shop or which ones are the better type. Babe in the woods.

As for the distribution amp (for the 10 MHz signal from the Trimble and another ovenized backup oscillator), I'll certainly listen to any hints you have for me. I really appreciate the help here Demian, thank you! I was planning to build the replacement amps as detailed on the NIST web site. I hear that the transformers on the old coax network cards work well for this. I have a couple so I can try a prototype before committing large resources to this project. The best counter I have is an HP 5335A with an upgraded clock, then there is the Trimble GPS reference source as well. I suspect that trying to measure jitter with this equipment may be difficult, but I'll try. That 5335A is the best counter I have ever worked with so far. I didn't care much for the Racal the lab used, and we couldn't certify my counter as a result of the quality of the 5335A. With the GPS signal, performance will go up on everything in my lab.

I am learning this new area (for me). I understand baseband stuff well, but the RF stuff is something I've avoided since before high school. So much of what you are saying can stretch my comprehension. It's probably pretty basic stuff once you know it. I do have patience and time on my side though.
Quote:
... possibly the LME49713 could be a real winner
I didn't consider a chip could work well at these higher frequencies due to the internal capacities coupled with small dimensions. I'll have a look at the data sheet - thanks again.
Quote:
... the best ones have carefully tuned input and output networks ...
I am comfortable with the idea of building the distribution amps old school. Transistors and coils aren't that intimidating to me. I see the NIST amps use strip-line techniques to aid in tuning. Difficult to go back though!
Quote:
... which you need the return loss bridge for ...
Okay, I'm sunk unless I can figure out another way around this. $550 for the 60A50 SWR Bridge is far too dear for me now. Sticker shock.
Quote:
I have a DA with a bunch of extra modules for 10 MHz (I think) that I'm not using. Let me know if its interesting and I'll get back to you with details.
Please, can you do that then? As I mentioned, I have an HP 5087A to modify + fix (no doubt). I do require more channels than are provided on the HP. Stanford is advertising a nice looking one. Of course it's well out of range for me.
So, I don't know much about the nuts and bolts of using these. I have the faintest idea what some of these accessories do and that's about it. Anything I buy will be a while - fixed income these days. You never know, and I would be interested to speak with you on these things.

I'm going to open a thread and move this information. I'll leave a director for you.

-Chris
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Old 14th May 2010, 04:20 AM   #4
davada is offline davada  Canada
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Hi Chris

Here's a couple more sources you can check.

Welcome to Imagic Design Ltd.
Sphere's Used Electronic Test Equipment

I'm in the market for a distortion analyzer so I'm heading back to the other thread.

David.
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Old 14th May 2010, 05:15 AM   #5
1audio is online now 1audio  United States
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You have a Thunderbolt? Lots of info on the web and in the time-nuts list for those.
I'm leaving for a week in the AM. I'll get the details on that DA when I'm back. PM me if you don't hear back.

The return loss bridge doesn't need to be that expensive. If you have time I may be able to facilitate some research in various projects.

Measuring jitter is very involved. You really need a 5370 at a minimum to see jitter. Or a Wavecrest. However if you have a reference oscillator or two at the target frequency, a mixer and a sensitive FFT (think soundcard) you can get the phase noise which can transforme to jitter. But much more important you can see what the phase noise is composed of, much more useful. The links start here: Techniques for Measuring Phase Noise and here: Low Phase Noise Systems - Hints and Tips but only get more interesting.

The LME49713 has potential in this because its a CFB opamp with a really wide power bandwidth (30 MHz) and low noise.
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Old 24th August 2010, 12:56 AM   #6
anatech is offline anatech  Canada
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Hi Demian,
Thank you, I'll check those links.

I do have a Thunderbolt, but it wasn't discipling. I have put the antenna back three times now and my wife keeps moving the damn thing! Girls drive guys absolutely crazy with the things they do! I'm telling you!

Sorry for the delay as well. I'm feeling less well these days and that restricts my "up time".

-Chris
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