RF signal generators

E4436B ? Obsolete.. you might get a good deal. The replacement is $45K, glad to hear that there's enough profit for it to be a problem. ;-)

Ask for a bonus!

Cheers

Phil Hobbs

Grin, Well there is some profit sharing at the end of the year. Just don't tell the other employee's that we buy new tech 'toys' before figuring what the profit is/ was.

Say if I have a GHz spectrum analyzer with a tracking generator can I just use the tracking generator as a swept RF source? That might be better than a signal generator for lots of things. (Can you park the tracking generator at one frequncy?)

George H.

Yeah some for a few $k on ebay.

George H.

Any thoughts on an Agilent EE4436B? (250 kHz to 3GHz.)

Thanks

George H.

What would be the use of 50MHz ? 500MHz maybe....What RF stuff runs at

AFAIK yes and yes. The only downside is that you probably can't modulate the signal. Rigol has a bunch of new spectrum analysers for very reasonable prices so you can buy new for half the price of second hand.

LOADS of RF stuff runs at

Well sure I've got a DDS func. gen. that does DC to ~50MHz.

If audio stops at 100k - 1MHz,

Then there's plenty of stuff to do.

pulsed nmr in permanent magnets ~20MHz.

diode laser modulation, there's phyiscis from 1MHz to 6.8GHz.

(Hmm, other stuff too... but most of it's on the same theme, an electron (atomic) spin resonance at lowish fields, or a nuclear spin at ~1T fields.)

George H.

There's this coax-impedance matching, 1/4 wavlength

hat

st

(Unless I hack it... I was just watching David Jones do a tear down of the Rigol on his eevblog.)

Rigol has a bunch of new spectrum analysers for

I downloaded their manual, but haven't read through it yet...

So if I park the TG, I get something like a noisy VCO output at the right frequency? That could work.

I must admit a spectrum analyzer, would be more useful than a signal generator.

(maybe we should get both!)

George H.

ed text -

id only $195 for it! It does have a problem with the PSU section, though, t he seller said. Needs a fancy new electrolytic that Tek wants about $250 fo r. Not sure why it's so expensive, but since I'm only a hobbyist I could pr obably get away with a regular electrolytic cap for a fraction of the price , I reckon. If anyone knows better and I'm likely to screw the thing up, pl ease disabuse me of my ignorance!

Hmm, see if you can find out what the 'fancy' part of the spec is, more or less ESR would be my niave guess. Then, given the specs, someone here may be able to recommend a cheaper one.. with maybe some testing on your end to find a good cap in the lot. (You use the others for other projects.) I've been picking the low esr 'cheeries' out of our 10uF tant, bin to use in this LT voltage regulator. (I sometimes think I should just trash it. It's fussy and noisy.)

George H.

"George Herold"

My boss is looking to spend some of this years profit. He?s been lusting after an RF signal generator. (We could use something that would go above 50MHz.) I know very little about them, and so I am looking for any recommendations, or brands to stay away from.

Unless you just want something to prop the door open with....

..... Phil

Sure, just set the analyzer to zero span.

Cheers

Phil Hobbs

Since the spectrum analyzer has a tracking filter, the built in signal generator may not be as pure as a stand alone signal generator. However, this should all show up in the specs. The same goes for step size. I have seen some spectrum analyzers with modulation sources. I think it was a Marconi.

You do know that a network analyzer is way sexier than a spectrum analyzer. You can do stuff like model chip components, or better yet, evaluate chip components to see which are better. You would need to insure the network analyzer has an impedance bridge and a suitable fixture for chip components.

As a bonus, you can sweep your homemade antennas on the network analyzer. Just don't tell the FCC since this is basically QRM unless you have a anechoic test facility.

It depends a lot on what you want to do with it. If you want plain basic functionality (CW, AM, FM) an old Agilent 8648C would fit.

The 4436B, although obsolete as others have pointed out, is a great instrument (I have an 4431B here, sadly only up to 2 GHz missing the 2.4 GHz band). Depending on what you want, you may like some of the options. We have the internal baseband generator for IQ generation which might be interesting depending on the application.

Then, you have the 8267 models, which are big $$... BTW, we have to ship our unit back to troubleshoot, thank god we had a warranty extension!

We also have an older Rohde&Schwarz SMIQ04. A good instrument with a particular user interface.

Regarding failures: We have had a significant number of failures with Agilent equipment. Had to have the 4436 and now the 8267 repaired. Same with a 20 GHz VNA (PNA-L). We had two of the nice 33250A 80 MHz function generators failing. A power supply was sent back twice until it started working properly for the first time... IMO this should not happen with a vendor of good reputation. Regarding Rohde's, we had to send in the generator because of an LCD issue.

Pere

You may consider one of the handheld network analyzers that are available. They are not top notch in terms of performance but they are quite versatile.

Pere

On Thu, 13 Dec 2012 10:39:27 +0100 o pere o wrote in Message id: :

Here's a nice bit of info for anyone with those LCD problems (lines, etc) The Rohde CMD80 uses the same display and can be had for peanuts on Ebay.

I have an SMIQ02 that had a bad display with tons of lines in it. Took a chance and bought a CMD80 off Ebay and it dropped right in and worked perfectly.

It's currently for sale if the OP is interested. Been sitting on it for awhile and would sell it for $850 + shipping CONUS only.

Oh there was a fancy HP/ Agilient network analyzer at the Vanderbilt FEL when I was there. But it was under someone elses supervision and I wasn't allowed to play with it. I think it cost north of ~$50k circa late 90's.

George H.

some of this years profit.  He?s been

Thanks Pere. Glad to hear that you like the 4431B. There are several on ebay for not too much money. Part of the problem is that we have only nebulous plans of what to do with it. A swept RF source would be useful for some experiments.

George H.