Author Topic: Spectrum Analyzers: Old Big Iron or New from China?  (Read 5648 times)

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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #25 on: October 18, 2018, 11:15:10 pm »
Nobody mentioned this so far, but another BIG difference is, old SA's have YIG oscillators and YIG filters in them, which means much cleaner LO generation. That's one reason I'm working hard to get my 22 GHz HP 8592B to work!

The lower price SA's from Siglent and Rigol don't have YIG oscillators/filters in them. But the big bux Keysight/Tektronix/RS probably have YIG's in them, not sure about that. How much impact will the YIG vs VCO LO generation have, that I don't know ...

Good to know, thanks. I've pretty much settled on waiting a while keep my eyes open for a deal on a really top end SA. Hopefully by then I'll have the bench space too. :)
 

Online BravoV

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #26 on: October 19, 2018, 04:20:39 am »
But as others have mentioned just the SA is only the start, cabling, adapters, attenuators, loads, and directional couplers can soak up a heap more funds to become even moderately well equipped.

+1 , beware of these accessories which personally I called "RF plumbing stuffs", top brand ones even used can still quite pricey. In my case, as I got my SA pretty cheap (posted at used SA guide too), these overall plumbing stuffs even at minimal, cost almost the same as my SA.  :'(

Depends on the SA acquired, suggesting to start learn/look/lurk for these stuffs too apart from the SA, cause sometimes this activity alone will take quite sometimes & energy to accumulate, let alone the cost.

As tautech pointed above, my suggestion for starting point sorted by priority imo : sacrificial connector, DC block (if needed) .. various attenuators ... and so on ...  :palm:

Just an example of small portion part of the plumbing stuffs, these used things alone cost > 50 bucks  ..  ::)
« Last Edit: October 19, 2018, 04:27:16 am by BravoV »
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #27 on: October 19, 2018, 04:48:31 am »
But as others have mentioned just the SA is only the start, cabling, adapters, attenuators, loads, and directional couplers can soak up a heap more funds to become even moderately well equipped.

+1 , beware of these accessories which personally I called "RF plumbing stuffs", top brand ones even used can still quite pricey. In my case, as I got my SA pretty cheap (posted at used SA guide too), these overall plumbing stuffs even at minimal, cost almost the same as my SA.  :'(

Depends on the SA acquired, suggesting to start learn/look/lurk for these stuffs too apart from the SA, cause sometimes this activity alone will take quite sometimes & energy to accumulate, let alone the cost.

As tautech pointed above, my suggestion for starting point sorted by priority imo : sacrificial connector, DC block (if needed) .. various attenuators ... and so on ...  :palm:

Just an example of small portion part of the plumbing stuffs, these used things alone cost > 50 bucks  ..  ::)


Hmm, good point. Additionally, I thought Tek oscilloscope probes were expensive till I saw the prices that even old HP RF probes go for too.
 

Online BravoV

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #28 on: October 19, 2018, 05:39:24 am »
Hmm, good point. Additionally, I thought Tek oscilloscope probes were expensive till I saw the prices that even old HP RF probes go for too.

LOL ... I can see you've seen and opened a nasty can of worm, arent you ?  :-DD

Yep, those high freq GHz range RF probes are pricey, trust me, I've lurked and waited patiently for years, and finally able to grab one at decent price. Its a HP 54701A 2.5GHz active probe, aged > 3 decades  ::), complete with it's "accessories", emphasized on the word "accessories" as at above few hundreds of MHz, probing technique and accessories becomes really matter, plain probe alone won't cut it, say compared like using passive probe. So take note on this tiny matter if you plan to buy an used one.




I have similar situation as you, as hobbyist, my best scope is Tek 2465B too, which is max at 400MHz as you aware of. Below photo quoted from your post from other 2465B thread if you don't mind, as signal above 400Mhz will be attenuated, coupled with a RF probe + a SA + correct probing technique & tools, I've been acquiring signals that I've never been able to see and measure with decent accuracy before.

As only hobbyist, I'm content and find this situation is a decent & reasonable compromise, rather than buying GHz capable scope which is overkill, at least for me.

 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #29 on: October 19, 2018, 06:55:36 am »
Hmm, good point. Additionally, I thought Tek oscilloscope probes were expensive till I saw the prices that even old HP RF probes go for too.

LOL ... I can see you've seen and opened a nasty can of worm, arent you ?  :-DD

Yep, those high freq GHz range RF probes are pricey, trust me, I've lurked and waited patiently for years, and finally able to grab one at decent price. Its a HP 54701A 2.5GHz active probe, aged > 3 decades  ::), complete with it's "accessories", emphasized on the word "accessories" as at above few hundreds of MHz, probing technique and accessories becomes really matter, plain probe alone won't cut it, say compared like using passive probe. So take note on this tiny matter if you plan to buy an used one.




I have similar situation as you, as hobbyist, my best scope is Tek 2465B too, which is max at 400MHz as you aware of. Below photo quoted from your post from other 2465B thread if you don't mind, as signal above 400Mhz will be attenuated, coupled with a RF probe + a SA + correct probing technique & tools, I've been acquiring signals that I've never been able to see and measure with decent accuracy before.

As only hobbyist, I'm content and find this situation is a decent & reasonable compromise, rather than buying GHz capable scope which is overkill, at least for me.



Yeah...it's one hell of a can of worms.  :-DD No worries on the photo; definitely illustrative of your point. I might have missed it above, what what SA do you run?

Looks like that model of probe is actually within reach pricewise...I was finding newer ones than that in the $3-5000 range (or more) and they were STILL old. 
 

Online BravoV

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #30 on: October 19, 2018, 07:18:40 am »
Yeah...it's one hell of a can of worms.  :-DD No worries on the photo; definitely illustrative of your point. I might have missed it above, what what SA do you run?

Looks like that model of probe is actually within reach pricewise...I was finding newer ones than that in the $3-5000 range (or more) and they were STILL old.

Its not widely known, a Korean made called Nex1 NS-30 9KHz-3GHz, posted the detail in the "Used SA guide" too, the OP didn't update it in the list, click here -> Nex1 NS-30 , 9KHz-3GHz & photos

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #31 on: October 19, 2018, 08:22:40 am »
Yeah...it's one hell of a can of worms.  :-DD No worries on the photo; definitely illustrative of your point. I might have missed it above, what what SA do you run?

Looks like that model of probe is actually within reach pricewise...I was finding newer ones than that in the $3-5000 range (or more) and they were STILL old.

Its not widely known, a Korean made called Nex1 NS-30 9KHz-3GHz, posted the detail in the "Used SA guide" too, the OP didn't update it in the list, click here -> Nex1 NS-30 , 9KHz-3GHz & photos

Very interesting! At this point I'm thinking my best bet is to learn as much as I can and wait for a deal, preferably when I am able to get more bench space. Then steel myself for the accessories purchases. I think I really want a nice 8566B...not only is it a fine instrument but my inner nerd just loves the fact that you can buy a lab grade instrument that cost as much as a house new and have it at home today.
 

Offline nctnico

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #32 on: October 19, 2018, 10:04:01 am »
1) What are reasonable prices in 2018 to be paying for working HP "big iron" SAs such as 8566, 8568? Some of the ones I'm seeing on ebay seem to be very highly priced considering their age, even considering the instrument cost as much as a nice car or even a house new.
IMHO the old SAs from HP are way overprized. These are also very old and their specs are not as good as modern gear. Other brands like Anritsu and Advantest also make very good spectrum analysers and good deals can be found on Ebay if you have a little bit of patience.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #33 on: October 19, 2018, 08:34:11 pm »

IMHO the old SAs from HP are way overprized. These are also very old and their specs are not as good as modern gear. Other brands like Anritsu and Advantest also make very good spectrum analysers and good deals can be found on Ebay if you have a little bit of patience.

But I'd have to get a mortgage to afford a new one with similar capabilities, so there's no free lunch. I'm keeping my eyes open and I'm not in a hurry to buy anything just yet. :)
 

Offline Bud

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #34 on: October 19, 2018, 08:46:28 pm »
1) What are reasonable prices in 2018 to be paying for working HP "big iron" SAs such as 8566, 8568? Some of the ones I'm seeing on ebay seem to be very highly priced considering their age, even considering the instrument cost as much as a nice car or even a house new.
IMHO the old SAs from HP are way overprized. These are also very old and their specs are not as good as modern gear. Other brands like Anritsu and Advantest also make very good spectrum analysers and good deals can be found on Ebay if you have a little bit of patience.

I am curious which specs exactly are not as good?
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Offline nctnico

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #35 on: October 19, 2018, 09:21:28 pm »

IMHO the old SAs from HP are way overprized. These are also very old and their specs are not as good as modern gear. Other brands like Anritsu and Advantest also make very good spectrum analysers and good deals can be found on Ebay if you have a little bit of patience.
But I'd have to get a mortgage to afford a new one with similar capabilities, so there's no free lunch. I'm keeping my eyes open and I'm not in a hurry to buy anything just yet. :)
You don't need a mortgage. For less than $2000 you can buy very nice used gear from Advantest or Anritsu for example.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline DaJMasta

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #36 on: October 19, 2018, 09:39:58 pm »
I am curious which specs exactly are not as good?

Looking at the datasheet for the HP 8568, a more modern instrument would have....
Lower DANL, spurious harmonics, level accuracy uncertainty, RBW options, VBW options
And better sweep speed, number of points in sweep, timebase spectral purity and phase noise, measurement capabilities (number of markers, channel power, etc.), input protection in many cases...

And that's just looking at the surface level stuff.  Look at the amplitude range on the 8568A, +30dBm to -135dBm.  Even with a 10Hz RBW (instead of 1Hz with averaging to get best results), the DANL of either the Rigol or the Siglent is lower than the 8568A can even display according to specification, the sweep has many more measurement points and is still very fast, the timebase has lower phase noise, etc.


People often put old gear they grew up revering on a pedestal, and while there is some very good old gear and some old gear which is nearly as good as the top of the line stuff (I'm looking at you 8.5 digit DMMs), the vast majority of equipment has improved DRAMATICALLY from the early 80s or wherever your vintage HP bit of kit of choice is from.  An entry level modern bench SA will preform better than nearly any top end system from the 80s.... and why would anyone expect differently?  Now, there are service manuals available, and the build quality is good, and you're probably used to the interface if you've used them before... there are a lot of value propositions for valuing the older gear, but there is really no benefit to assuming a giant old SA is going to preform better than a newer one, especially when nothing on the datasheet suggests it.
 
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Offline KE5FX

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #37 on: October 20, 2018, 12:38:44 am »
IMHO the old SAs from HP are way overprized. These are also very old and their specs are not as good as modern gear. Other brands like Anritsu and Advantest also make very good spectrum analysers and good deals can be found on Ebay if you have a little bit of patience.

Not all specs appear on a spec sheet.  The ability to flip the power switch on my 8566B and instantly measure power levels within 0.5 dB of a comparable measurement made 6 months ago is why that particular boatanchor is still on my bench.

Quote
You don't need a mortgage. For less than $2000 you can buy very nice used gear from Advantest or Anritsu for example.

... which you may not be able to maintain due to lack of service information. 

Those companies' business model was to copy similar instruments from -- you guessed it -- HP.  At this point, you might as well get the real thing.

The best advice is really to buy something cheap and see what limitations you encounter with it, then use that insight to decide what to get next.   You don't want to be the guy who buys the most expensive guitar in the store before you take your first lesson.
 

Offline KE5FX

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #38 on: October 20, 2018, 12:43:16 am »
Looking at the datasheet for the HP 8568, a more modern instrument would have....
Lower DANL, spurious harmonics, level accuracy uncertainty, RBW options, VBW options
And better sweep speed

Yes, hard to beat an FFT in that department.

Quote
number of points in sweep

1001 is plenty.

Quote
timebase spectral purity and phase noise

LOL, fat chance.  Maybe out past 100 kHz...

Quote
Even with a 10Hz RBW (instead of 1Hz with averaging to get best results), the DANL of either the Rigol or the Siglent is lower than the 8568A can even display according to specification, the sweep has many more measurement points and is still very fast, the timebase has lower phase noise, etc.

Lower DANL == they put a $2 preamp in front of the first mixer.  That's about what it would cost you to add your own to an 8568.
 

Offline tkamiya

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #39 on: October 20, 2018, 01:24:50 am »
If it wasn't HP's popularity and abundance in market, I wouldn't have FOURTEEN SAs in my house. :scared:

Parts are plenty available too....  In fact, I have my own stock of parts.

If I have to carry it around, I would go with Rigol or Siglent in a heartbeat.  But for stationary lab work, I like my setup.  One difference between old stuff and new are use of buttons vs menus.  I have a modern scope.  It's nice to hit AUTO and get something to show on display.  But if I have to change anything, it's often menu, up, up, push, twist, push.  I can't remember what's where.  Old stuff has each function assigned to well labeled knobs and switches.  I don't have to refer to manuals so often.  It took me a read on manual to find where AC/DC couplings were hiding.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #40 on: October 20, 2018, 02:00:42 am »


The best advice is really to buy something cheap and see what limitations you encounter with it, then use that insight to decide what to get next.   You don't want to be the guy who buys the most expensive guitar in the store before you take your first lesson.

I may have found a deal on a 8569B that the seller says works, actually. I think I understand from the buyer's guide that the 856X is always better in RF performance than other models. I don't think it has as low RBW as the big boys, but it could be fun for a first one.
 

Offline tkamiya

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #41 on: October 20, 2018, 02:23:30 am »
Oh, one more thing....

I had a conversation with calibration/repair technician and he mentioned that:

If you go outside of HP/Agilent/whatevernext, parts availability and documentation availability can suffer.  For HP, owner's manual, technical manual, repair guide, tuning guide, etc, are readily available.  Parts show up often on eBay.  Not so for other brands.  Many Japanese makes did not release their manuals to public like HP did, and parts are almost non-existent.  You'll end up needing to do a parts level repair without much of guides.  This is why I stay with HP and Tektronix.  Everything is SO available.  Being an old stuff, they will need maintenance.  Before you make a decision, my recommendation is to look to online resources to see what you can get, parts and manual wise.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #42 on: October 20, 2018, 02:29:35 am »
Oh, one more thing....

I had a conversation with calibration/repair technician and he mentioned that:

If you go outside of HP/Agilent/whatevernext, parts availability and documentation availability can suffer.  For HP, owner's manual, technical manual, repair guide, tuning guide, etc, are readily available.  Parts show up often on eBay.  Not so for other brands.  Many Japanese makes did not release their manuals to public like HP did, and parts are almost non-existent.  You'll end up needing to do a parts level repair without much of guides.  This is why I stay with HP and Tektronix.  Everything is SO available.  Being an old stuff, they will need maintenance.  Before you make a decision, my recommendation is to look to online resources to see what you can get, parts and manual wise.

Repairability is definitely always a plus. I have found PDF of the 8569B operators and service manuals online already.
 

Offline KE5FX

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #43 on: October 20, 2018, 02:43:56 am »
I may have found a deal on a 8569B that the seller says works, actually. I think I understand from the buyer's guide that the 856X is always better in RF performance than other models. I don't think it has as low RBW as the big boys, but it could be fun for a first one.

At the right price, sure.  It's less capable than either the huge benchtop analyzers or the newer portables, so the price should be lower as well. 
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #44 on: October 20, 2018, 03:31:08 am »
I may have found a deal on a 8569B that the seller says works, actually. I think I understand from the buyer's guide that the 856X is always better in RF performance than other models. I don't think it has as low RBW as the big boys, but it could be fun for a first one.

At the right price, sure.  It's less capable than either the huge benchtop analyzers or the newer portables, so the price should be lower as well.

It's listed for 350 and the seller is taking offers.
 

Offline Tony_G

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #45 on: October 20, 2018, 04:30:36 am »
Repairability is definitely always a plus. I have found PDF of the 8569B operators and service manuals online already.


Artem Manuals is a great resource for quality scans of old manuals. KO4BB is also outstanding.

TonyG
 
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Offline rx8pilot

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #46 on: October 20, 2018, 04:32:41 am »

Artem Manuals is a great resource for quality scans of old manuals. KO4BB is also outstanding.

TonyG

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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #47 on: October 20, 2018, 07:51:42 am »
 

Offline rf-loop

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #48 on: October 20, 2018, 08:17:20 am »


The best advice is really to buy something cheap and see what limitations you encounter with it, then use that insight to decide what to get next.   You don't want to be the guy who buys the most expensive guitar in the store before you take your first lesson.

I may have found a deal on a 8569B that the seller says works, actually. I think I understand from the buyer's guide that the 856X is always better in RF performance than other models. I don't think it has as low RBW as the big boys, but it could be fun for a first one.

Check carefully that all front panel adjustments works 100% and not just intermittently or some step not at all. It is real nightmare if they are not in good condition. If it need repair it really need know how to do and then even more importantly, what must not do.  (there is available quite good instructions for repair - service work)

Years ago I have owned one of this SA (yes it was nearly like "new")

This front panel is this SA's "Achilles heel"  if it is handled using "heavy hand". Also there is some plastic parts what may break even without touching just due to some material ageing.

Here is one example what I mean is "Achilles heel"
 And here.
(I think some years in history HP use this construction in many places. It can ask what they smoke these years there)

« Last Edit: October 20, 2018, 08:22:18 am by rf-loop »
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #49 on: October 20, 2018, 08:21:52 am »


The best advice is really to buy something cheap and see what limitations you encounter with it, then use that insight to decide what to get next.   You don't want to be the guy who buys the most expensive guitar in the store before you take your first lesson.

I may have found a deal on a 8569B that the seller says works, actually. I think I understand from the buyer's guide that the 856X is always better in RF performance than other models. I don't think it has as low RBW as the big boys, but it could be fun for a first one.

Check carefully that all front panel adjustments works 100% and not just intermittently or some step not at all. It is real nightmare if they are not in good condition. If it need repair it really need know how to do and then even more importantly, what must not do.  (there is available quite good instructions for repair - service work)

Years ago I have owned one of this SA (yes it was nearly like "new")

This front panel is this SA's "Achilles heel"  if it is handled using "heavy hand". Also there is some plastic parts what may break even without touching just due to some material ageing.

Here is one example what I mean is "Achilles heel"
(I think some years in history HP use this construction in many places. It can ask what they smoke these years there)

Thanks for the heads-up! At least it's fixable. TBH if the deal works out the price is low enough I'm not too worried.
 


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