Spectrum analyzer recommendations

[jackhackett]

I'm looking for a new spectrum analyzer for our shop, mostly going to be used for tuning duplexers. Any recommendations?

[willbartlett]

I don't know what other needs you have for it, but an hp 8920a or b, is a pretty nice unit to have. In addition to the spectrum analyzer, it does support a tracking generator for some basic scalar network analyzer use, plenty for tuning duplexers. I've done a bunch with mine, no complaints at all. It's also a kick-@$$ service monitor. they can be had for $3-5k. Be sure you get one with option 102. do your research on them as well. Alternately, there is a unit called an 8924C which was a TDMA or CDMA service set, but it has all the same features as the 8920, it's just bigger, like 75 lbs. and full rack width. Not something to bring to a site. Those can be had, used, refurb with a warranty and cal for about $1600. Pretty fair price for the features.

Only drawback to the 8920 or 8924, is that they don't support any finer resoloution bandwidth as a spectrum analyzer that 300hz. They're more of a spectrum monitor that spectrum analyzer. but if you can live with that, you'll be more than happy with the rest of the unit.

If you just want a spectrum analyzer only, dig around for an hp 8590 or 8591. They are good to a minimum of 1.5ghz, depending on the model. Much finer control of bandwith, rock solid unit, can be had with some nice options for $2-3K. Don't pay more than $4k for one, the Ebay sellers have a greatly inflated sense of worth on those type of things. Not that I did it, but I've witnessed one rolled of the back of a truck on a corner and not sustain ANY damage other than the front cover getting cracked

Will

[Bruce1807]

R-2670
but really it depends what you want it for and what volume.

[Wowbagger]

Well, first you have to answer the question "Do you want a spectrum analyzer, or a service monitor?"

A service monitor won't be as good a spectrum analyzer as a dedicated spectrum analyzer, because a service monitor has to be so many other things as well - an RF source, a modulation source, etc. Also, the sorts of design decisions you make in an RF section for a spectrum analyzer are different from (and usually at odds with) the design decisions you make for a service monitor.

OK, full disclosure: This next bit is biased as hell.

If you want a service monitor with spectrum analyzer functions, and one of your main use cases is tuning duplexers, may I suggest you look into a COM-120B. One of the things I find very useful in tuning duplexers is the split-screen mode on the analyzer - in effect you have two (largely) independent analyzers side-by-side, each of which can have its own center frequency, span, resolution bandwidth, etc. The only settings shared are the input port and tracking generator level. Thus, you can set one side to be centered on one frequency of interest, and the other side to be the other frequency of interest, and zoom in to any desired span to see what is going on. For example, when I was tuning a duplexer for 146.82/146.22, I could center the left side on 146.22 and the right on 146.82, and then reduce the span on each side down to 50 kHz to get a really close look at the pass band and reject band.

The COM-120B also has the ability to offset the tracking generator from the analyzer center frequency, for sweeping IF filters - you can park the tracking generator at the radio's receive frequency, then move the analyzer center frequency to the IF frequency and directly image the IF filter response. (I put that feature in precisely because I needed to tune the IF on a radio, and when I thought about it I realized the 120's hardware could do that, it was just the software that needed to be changed. And as I was the lead software engineer on the project....)

[Al]

With all due respect to Wowbagger, I'd agree with him on the COM120B service monitor if you do indeed want a service monitor. A short time ago, I bought a spectrum analyzer from Aeroflex to replace the old A7550 that I used for quite a while based on the good results and support from Aeroflex[IFR] on both my COM120B and COM120A and A7550. I bought the Aeroflex 2399B, and it was a mistake. I wish I had bought the Agilent N1996A. The Aeroflex 2399B is made in Asia, optioned in the UK, and the documentation and customer support from Aeroflex customer service here in the US is *lousy* despite the fact that I spent an extra $400 for the service documentation. In spite of firmware bugs, I got the telephone equivalent of a blank stare when I asked about access to firmware updates to fix existing bugs and ATE calibration software.

[xmo]

You have many decisions to make: New or used, service monitor or dedicated analyzer, size [bench, portable, or handheld] vendor support, price range etc.

The service monitor recommendations posted here are excellent. The 8920 series are fantastic instruments with a good spectrum analyzer functionality. The COM120B also has excellent spectrum analyzer capability. On the other hand the Motorola / GD analyzers are less desireable. The 2600 series has sweep limitiations, only 60 dB of display dynamic range, awkward controls and is very slow.

For a dedicated portable spectrum analyzer at a mid range price I would recommend the Agilent ESA-E. These have been on the market for a few years so they are available both new and used. They come with various top end frequency ranges so you can choose dependent on possible other applications such as maintenance of microwave systems.

This series has many options available. When configured with the tracking generator it is an excellent tool for alignment of duplexers and filters as well as for performing antenna return loss sweeps using a return loss bridge. The latest firmware has some great features such as segmented sweep. This will allow you to define two or more [up to 32!] sweep segments anywhere in the instrument's range to be presented simultaneously across the screen.. This is not only useful for such things as looking at the TX & RX sides of a duplexer or the input and output of a repeater but can be used to look at a frequency that is being interfered with as well as separate segments for each of several potential interferrers.

The ESA is blazingly fast - you can't believe how fast until you see it in action. It has internal storage for retaining setups, traces, screen shots and so on. There is a floppy for exporting these files. You can also connect it to a PC in a variety of ways for file transfer or PC control. There is even a software package called web remote that will allow you to control the machine remotely over the internet just as if you were there with it. That package has a great waterfall smectrum monitoring display. You can also use the excellent spectrum monitoring software from John Miles, KE5FX.

There is great documentation for these instruments which you can download from Agilent before you buy. You can even run a simulated version of the instrument through the web remote demo on their web site. There are also many great free spectrum analyzer applications available from Agilent's web site.

[Bruce1807]

I have Rohde & Schwarz hand held for field use (dont use it to much compared to the service monitor) but it works flawlessly.

Anyone know what happened to Birds speccy I think it was the SH-36 or similar.
I saw it at APCO last year but never saw it on the market.

[jackhackett]

Thanks for the replies.
I literally meant a "new spectrum analyzer for the shop". Don't need a service monitor, we've got a shop full of 2670s, the analyzer in these really isn't good enough anyway. Not really looking for used (but if a really good deal came up), and it's going to be strictly for shop use, so going for a benchtop (knowing our road techs, if I got a portable one I'd never get to see it again).
My main use at the moment would be tuning duplexers, so I need something with good dynamic range and a low noise floor to see those really weak signals when notching, and check the pass loss... and a tracking generator wouldn't hurt.
I downloaded some information about a couple of Agilent's models.. I think it was the 1996 and 1920.. they look like they might do the job, still open to suggestions/comments though.

[Wowbagger]

I bought the Aeroflex 2399B, and it was a mistake. I wish I had bought the Agilent N1996A. The Aeroflex 2399B is made in Asia, optioned in the UK, and the documentation and customer support from Aeroflex customer service here in the US is *lousy* despite the fact that I spent an extra $400 for the service documentation. In spite of firmware bugs, I got the telephone equivalent of a blank stare when I asked about access to firmware updates to fix existing bugs and ATE calibration software.

Tell you what: I'll forward your message on to the appropriate person at work as an FYI.