Author Topic: Spectrum Analyzers: Old Big Iron or New from China?  (Read 5671 times)

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Offline KE5FX

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #50 on: October 20, 2018, 09:17:14 am »
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.

Yeah, you'll get $350 worth of entertainment value out of it if nothing else.  :-+ That's a good price for an instrument with coverage from HF to K-band, as long as it works or can be fixed economically.
 

Offline nctnico

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #51 on: October 20, 2018, 10:22:57 am »
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. 
So far Advantest SAs have proven to be perfectly fixable without schematics or service manual. But then again equipment which is newer is less likely to break anyway.
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 #52 on: October 20, 2018, 09:14:59 pm »
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.

Yeah, you'll get $350 worth of entertainment value out of it if nothing else.  :-+ That's a good price for an instrument with coverage from HF to K-band, as long as it works or can be fixed economically.

I may be able to get it for $300, waiting on the seller.
 

Offline G0HZU

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #53 on: October 20, 2018, 10:04:19 pm »
Quote
1) What are reasonable prices in 2018 to be paying for working HP "big iron" SAs such as 8566, 8568?
I bought my HP8566B as an ex rental from a large TE rental company for £1000 about 7 or 8 years ago. At the time this was a huge bargain but I did have to do a few minor repairs to it over the first couple of years. Nothing difficult or expensive but these old analysers are starting to suffer with cap failures that often affect the YIG operation. So the analyser can show signs of sweep instability when this happens.

Today, I'd still expect a healthy HP8566B to be about £1200-£1500 here in the UK. A less healthy example might be half this price but you can expect to be taking it apart quite a bit to clear all the niggles.

In 2018 I'd run a mile from the HP8569B unless I was just going to use it for very basic ham related testing across various ham bands up into the microwave bands. $300 is a good price but I'd still rather spend more and get something decent. Are you sure you know what you are compromising if you buy the HP8569? In 2018 this analyser is a bit of a dog compared to the alternatives unless you need a cheap analyser that can cover up to 20GHz or so. I haven't used a HP8569B for many years (and I don't want to) and I recall it doesn't work well at low frequencies so best used for VHF through the microwave bands.

The Siglent analyser looks to be a good alternative for home/hobby use. It has a digital IF and modern display and connectivity and lots of modern features. It can't compare to something like the HP8566B when you compare the design integrity of the RF converter section but it does have a significant advantage for many applications because of its modern digital IF. It is also new and comes with a warranty.  Unless you need the RF design integrity of something like the HP8566B then the Siglent analyser is going to be the more powerful choice IMO.
 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #54 on: October 20, 2018, 10:08:54 pm »
Quote
1) What are reasonable prices in 2018 to be paying for working HP "big iron" SAs such as 8566, 8568?
I bought my HP8566B as an ex rental from a large TE rental company for £1000 about 7 or 8 years ago. At the time this was a huge bargain but I did have to do a few minor repairs to it over the first couple of years. Nothing difficult or expensive but these old analysers are starting to suffer with cap failures that often affect the YIG operation. So the analyser can show signs of sweep instability when this happens.

Today, I'd still expect a healthy HP8566B to be about £1200-£1500 here in the UK. A less healthy example might be half this price but you can expect to be taking it apart quite a bit to clear all the niggles.

In 2018 I'd run a mile from the HP8569B unless I was just going to use it for very basic ham related testing across various ham bands up into the microwave bands. $300 is a good price but I'd still rather spend more and get something decent. Are you sure you know what you are compromising if you buy the HP8569? In 2018 this analyser is a bit of a dog compared to the alternatives unless you need a cheap analyser that can cover up to 20GHz or so. I haven't used a HP8569B for many years (and I don't want to) and I recall it doesn't work well at low frequencies so best used for VHF through the microwave bands.

The Siglent analyser looks to be a good alternative for home/hobby use. It has a digital IF and modern display and connectivity and lots of modern features. It can't compare to something like the HP8566B when you compare the design integrity of the RF converter section but it does have a significant advantage for many applications because of its modern digital IF. It is also new and comes with a warranty.  Unless you need the RF design integrity of something like the HP8566B then the Siglent analyser is going to be the more powerful choice IMO.

Yes, I am aware that it is a compromise. I mainly intend to use it for basic testing in and around ham bands. I suspect it won't be my only SA in coming years anyway.  :-DD At the very least, it will let me learn what I want in my next one for reasonable money, rather than spending $1500 or so and realizing it doesn't quite meet my needs.
 

Online tkamiya

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #55 on: October 21, 2018, 03:27:25 pm »
I think this is actually a reasonable approach.  $300 ish is an excellent price for ANY working spectrum analyzer.  Using it to learn will help him understand what his real requirements are.  My only concern is, because of price, I hope this is not too-good-to-be-true situation.  That's how I started with 1.8GHz box and recently got a 26.5GHz box. 

Pretty much with hobbyist budget, every SpecAn will be a compromise.
 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #56 on: October 21, 2018, 04:35:40 pm »
I think this is actually a reasonable approach.  $300 ish is an excellent price for ANY working spectrum analyzer.  Using it to learn will help him understand what his real requirements are.  My only concern is, because of price, I hope this is not too-good-to-be-true situation.  That's how I started with 1.8GHz box and recently got a 26.5GHz box. 

Pretty much with hobbyist budget, every SpecAn will be a compromise.

On the other hand, if it turns out to be a repair project, I'll learn from that too. I think it should be serviceable though. Seller has 100% positive rep. He says the front panel is in good order.
 

Offline KE5FX

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #57 on: October 21, 2018, 08:34:14 pm »
The 8569B could be a good companion to an SSA3021X or similar unit.  It'd be very cost-effective for troubleshooting or experimentation in the microwave range, while the Siglent would give you a lot of useful features in the HF-2 GHz range. 

If you did want to look at the 2.4 GHz or 5 GHz band with the Siglent, you could put the 8569B in zero-span mode and use it as a downconverter.  Not sure if the 8569B had a wideband IF output jumper like the 8566B, but it's easy enough to add one if not.  At $300 it would make sense to view it as a good platform for modification.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #58 on: October 22, 2018, 02:54:05 am »
The 8569B could be a good companion to an SSA3021X or similar unit.  It'd be very cost-effective for troubleshooting or experimentation in the microwave range, while the Siglent would give you a lot of useful features in the HF-2 GHz range. 

If you did want to look at the 2.4 GHz or 5 GHz band with the Siglent, you could put the 8569B in zero-span mode and use it as a downconverter.  Not sure if the 8569B had a wideband IF output jumper like the 8566B, but it's easy enough to add one if not.  At $300 it would make sense to view it as a good platform for modification.

That's a great point. I'll definitely keep that in mind as the budget allows. In the meantime, I got on artek manuals and got all the manuals both for this SA and my HP 8657A signal generator.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #59 on: October 22, 2018, 06:06:43 am »
Now that I have an instrument on the way, I perused an old question someone asked about what accessories are must-have. So far on my shopping list:

1. Adapters. Lots of adapters.
2. RF attentuators (these seem to be rather expensive, so I'm going to check out a local surplus store I like first, before buying new)
3. DC block
4. Coax

Additionally, I figured on getting a few antennas. I was looking at the RF Explorer nearfield antenna set [1] on Amazon, as well as their power limiter [2]. Reasonably priced, but I assume you get what you pay for. Anything else in the must-have category? Recommended antennas? I was looking at these relatively cheap PCB based antennas [3]. Perhaps a directional antenna of some sort? Perhaps I should also make a post in the RF forum too.

[1]: https://www.amazon.com/gp/product/B01NBTPTOZ/
[2]: https://www.amazon.com/gp/product/B00IF8N1BO/
[3]: https://www.amazon.com/dp/B074QGYHJ2/
 

Offline G0HZU

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #60 on: October 25, 2018, 04:15:46 pm »
The 8569B could be a good companion to an SSA3021X or similar unit.  It'd be very cost-effective for troubleshooting or experimentation in the microwave range, while the Siglent would give you a lot of useful features in the HF-2 GHz range. 

Yes, I agree... it could be a powerful combination if the budget permits :)
 
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Online tkamiya

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #61 on: October 25, 2018, 06:33:25 pm »
Mini circuits have DC blocks that are much reasonably priced and they even go as high as 18GHz.

MCL has coax adapters with good spec for reasonable prices, too. 
 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #62 on: October 26, 2018, 04:39:55 pm »
Thanks, all!

I received The Beast! It seems to be working fine, I followed the initial adjustment procedure from the manual on the 100 MHz cal signal. The seller happened to have a bag of spare contacts for the front panel, too. He threw them in for free.



 

Online tkamiya

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #63 on: October 26, 2018, 04:45:35 pm »
You got yourself a heck of a deal!  Was this eBay? 

Your SpecAn looks beautiful and nearly new!  Often times, CRT of this vintage is dim and fuzzy.  Yours looks great!
 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #64 on: October 26, 2018, 05:01:56 pm »
You got yourself a heck of a deal!  Was this eBay? 

Your SpecAn looks beautiful and nearly new!  Often times, CRT of this vintage is dim and fuzzy.  Yours looks great!

Yep, ebay. It's got a few scuffs but considering it's age it looks great! I'm happy!
 

Offline TheSteve

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #65 on: October 26, 2018, 05:31:35 pm »
You gotta love that green screen!
VE7FM
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #66 on: October 27, 2018, 05:00:11 am »
You gotta love that green screen!

Heck yes! The only issue I uncovered was that the sweep speed dial may be messed up. All the settings work but they don't match up on the dial to what the screen readout is. Not a big deal though, since I have spare parts for the front panel.
 

Offline Tony_G

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #67 on: October 27, 2018, 06:55:55 pm »
The dial may have just been put back on incorrectly. If they used the same set screw from other units then a small Allen key is used to remove it.

TonyG
 
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Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #68 on: October 28, 2018, 04:25:19 am »
The dial may have just been put back on incorrectly. If they used the same set screw from other units then a small Allen key is used to remove it.

TonyG

Good call, I'll take a look at that.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #69 on: October 30, 2018, 03:33:25 am »
The knob was indeed loose, which I fixed. However, it's still a bit odd, as it ends up being one off when you turn it a full 360. I wonder if this is intended or not? Every single point of the switch makes contact though, as all the sweep times do work.

 Also, there's a rather strong signal that appears at 0.0 MHz that appears to be internal? There's nothing connected to the input in the attached image.
 

Online DaJMasta

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #70 on: October 30, 2018, 04:06:30 am »
That's the low frequency rolloff of the instrument and, because you're centered at zero, it's showing a sideband with power at a negative frequency, which of course is not really present.

It's good down to 10MHz by specification, and these are typically AC coupled (high pass filter), so you're going to have a peak that goes right up as the frequency approaches zero, but because you can move that over to the center, you also see the part of the plot that really doesn't represent data.


Just pointing out that the entire pictured range is out of spec - a 5MHz span centered around 0 would be real readings from 0-2.5MHz, but the specified performance starts at 10MHz.
« Last Edit: October 30, 2018, 04:08:43 am by DaJMasta »
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #71 on: October 30, 2018, 04:28:32 am »
That's the low frequency rolloff of the instrument and, because you're centered at zero, it's showing a sideband with power at a negative frequency, which of course is not really present.

It's good down to 10MHz by specification, and these are typically AC coupled (high pass filter), so you're going to have a peak that goes right up as the frequency approaches zero, but because you can move that over to the center, you also see the part of the plot that really doesn't represent data.


Just pointing out that the entire pictured range is out of spec - a 5MHz span centered around 0 would be real readings from 0-2.5MHz, but the specified performance starts at 10MHz.

Thanks, that makes sense. So basically I can ignore it.
 

Offline 0culus

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Re: Spectrum Analyzers: Old Big Iron or New from China?
« Reply #72 on: November 03, 2018, 06:37:43 am »
So I did some tuning accuracy tests on this 8569B and I'm impressed; it actually sits inside the specifications in the manual. I unfortunately don't have a microwave source yet, so I could only test the 0.1-1.8 GHz band with my RF generator, which is a limitation, but this is the band I'm using most at the moment anyway!

The manual states that tuning accuracy for the instrument's entire band (0.1-115 GHz; external mixing is required over 22 GHz) is +/- 5 MHz or 0.2% of center frequency (whichever is larger) +20% of frequency span per division.

My results are as follows. All measurements were taken with 500 KHz/div coupled 100 KHz RBW and no internal attenuation.

Internal 100 MHz calibration signal:
  • Center Freq: 100.0 MHz
  • Front Panel Readout: 0.100 GHz
  • Actual: 100.0 MHz

100 MHz signal from my 8657A @ -10 dBm, no modulation (which is bang on accurate according to my refurbed Tek 2465B):
  • Center Freq: 100.0 MHz
  • Front Panel Readout: 0.100 GHz
  • Actual: 100.0 MHz

Down in the low part of the band the SA is bang on.

1000 MHz signal from the 8657A @ -10 dBm, no modulation:
  • Center Freq: 1.0000 GHz
  • Front Panel Readout: 1.000 GHz
  • Actual: 1.0015 GHz

So up at 1 GHz, it's off by almost exactly +1.5 MHz. 0.2% of 1000 MHz is 2 MHz < 5 MHz, so it's easily in spec according to the manual, adding the 20% of [edit] RBW freq span/div is irrelevant in this case.

Now I realize there are probably way more precise ways to do this (and there are probably variables I'm not accounting for and it's likely farther off in higher bands...), but working with what I have, I'm quite impressed for the price and 34 years old.
« Last Edit: November 03, 2018, 05:16:36 pm by 0culus »
 


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