It has been a long time since I used either the Tek 492 or 2712 SA and wondered if anyone had a preference for either and why? looking for a good used one, not sure which yet.
Thanks
2712 vs 492 analyzer
Moderator: Queue Moderator
2712 vs 492 analyzer
"depending on your point of view, either the changing magnetic flux makes the electric field, or the changing electric flux makes the magnetic field- but you can't have one without the other"
-
richyradio
- Posts: 83
- Joined: Fri Dec 13, 2002 1:52 pm
...I guess it all depends what you want to use it for....most 492's go to 21 ghz, whereas the 2712 tops out at 1.8 gig...it seems to me the 2712 was the replacement for the Tek "7L" series as it has some features specifically designed for radio and ntsc television transmitters- (demodulated outputs) (geez, I never thought I'd be specifying anything other than ntsc, but now that 8VSB is here...) The '492 is a little older, and is more of a general lab instument...I own 3 '492's (I pretty much own 3 of anything that I know is no longer supported so I have a good collection of spare parts) and I am happy with them considering their limitations (I.E. abysmal frequency accuracy, plus/minus 1 mhz at band 1 and worse as you go up, but there's other ways around that) I've used the 2712 many times, they are somewhat better spec-wise, and has significantly better sensitivity, if you need to look "off air" ......but to me, there's something "flimsy" about them that I just can't put my finger on....(speaking of finger, you can lift the thing up with your pinky- not much rf plumbing in there, me thinks...plus the annoying beeper that goes off when you go out of cal, like when your sweep speed is too fast for desired resolution...I don't need a damn reminder every time I purposely decouple span/sweep/resolution! that feature will be your worst enemy if you use a 2712 to look at wireless mics on a "live" studio floor...you will get the most evil stares you have ever seen in your life...so I guess it's a toss-up between the two...not sure if the 2712 is supported either....probably not, as Tek barely supports stuff more than about 5 years old ...seems as though computers have re-defined the life span of all electronic equip....a 2712 with internal tracking generator might be nice...(short of an h/p 8563 of course!)
p.s. If you go w/ a '492 you will need the phase lock option (opt. 02 I think) as spans under 50 khz will jitter around...the digital storage option (03?) is useful too, if you want to look at the shoulders of digital signals...the slow sweep speeds required to observe them will make your eyeballs pop out of your head otherwise! Most come with options1,2&3 anyway, the other option being a YIG preselector for 1.8 to 21 gig ...that option you can take or leave as far as I am concerned, as the amount of extra parts/ modules is a bit excessive for what it does....(you don't want to know how many alignment pots are in a 492...)
pps. the early ones are different than later ones as far as the 2nd LO/ mixer is concerned - I'd try to get the later- i'll look up at what point the change was made serial number wise...
p.s. If you go w/ a '492 you will need the phase lock option (opt. 02 I think) as spans under 50 khz will jitter around...the digital storage option (03?) is useful too, if you want to look at the shoulders of digital signals...the slow sweep speeds required to observe them will make your eyeballs pop out of your head otherwise! Most come with options1,2&3 anyway, the other option being a YIG preselector for 1.8 to 21 gig ...that option you can take or leave as far as I am concerned, as the amount of extra parts/ modules is a bit excessive for what it does....(you don't want to know how many alignment pots are in a 492...)
pps. the early ones are different than later ones as far as the 2nd LO/ mixer is concerned - I'd try to get the later- i'll look up at what point the change was made serial number wise...
Hallo Richyradio, thanks for the info, you obviously have a lot of 492 operation in the past. I would appreciate any info regarding options and mods vs serial numbers. I do have a service monitor that is pretty good at frequency measurement (GD2590 with OCXO) but it seems to be easily overloaded in high fields at crowded sites (particularly at KMUN-FM here). It is also too expensive to leave lying around. So I thought it would be handy to have a 492 or 2712. Maybe they are better at handling overload, I don't know. Digital storage would be nice when you are just scanning for odd or suspect signals. Though I worked at Tek on scopes for 10 years I did not get much SA experience.
BTW the 2712 is supported at a flat rate of $2090 for cal plus any replacements or repairs. Don't know about the 492 though.
BTW the 2712 is supported at a flat rate of $2090 for cal plus any replacements or repairs. Don't know about the 492 though.
"depending on your point of view, either the changing magnetic flux makes the electric field, or the changing electric flux makes the magnetic field- but you can't have one without the other"
Tektronix made some great spectrum analyzers. It's a shame they abandoned that market to form business alliances with Advantest and Rohde and Schwartz - but test equipment is a tough marketplace.
492's are getting a little old these days. The 492 was a ground-breaking product for Tek when it was introduced in 1979. Lab quality in a portable package. The 494 came along four years later and added many desirable features including sysnthesized [zero drift] operation with high accuracy time base, direct keypad frequency entry, memory registers for saving instrument settings and traces, and direct output to a plotter [on P suffix GPIB equipped units].
Later models 492A/492B/492PGM/and 494A added a few other nice features like markers. The product then became the 279X series with an updated front panel. Those are the last decendents of the 490 family.
The 271X analyzers were economy units covering the RF frequency range. The 2710 was the first in that family. It was introduced introduced in the late 1980's. The series continued through the 2714 & 2715 which were among the last Tek manufactured spectrum analyzers.
The 490 series was also made as an RF range product [without the microwave bands], initially in the 496 and then the 495. The 495 has the advanced features [synthesized, etc.] of the later 492A/B/PGM & 494 units. This makes a great unit for the two-way tech.
There were also a 2750 series of rack width lab analyzers based on the 490 architecture with expanded front panels.
The high point of Tek's spectrum analyzer products is the 2780 series produced in the 1990's. They offered liquid crystal color display, calibration to 1.2THz, and are the only analyzers I am aware of that allow simultaneous display of analog and digital traces. These are highly prized for TSCM work and still bring real money [not a surprise since they cost on the order of $70K new and have features comparable to high end analyzers even today]
492's are getting a little old these days. The 492 was a ground-breaking product for Tek when it was introduced in 1979. Lab quality in a portable package. The 494 came along four years later and added many desirable features including sysnthesized [zero drift] operation with high accuracy time base, direct keypad frequency entry, memory registers for saving instrument settings and traces, and direct output to a plotter [on P suffix GPIB equipped units].
Later models 492A/492B/492PGM/and 494A added a few other nice features like markers. The product then became the 279X series with an updated front panel. Those are the last decendents of the 490 family.
The 271X analyzers were economy units covering the RF frequency range. The 2710 was the first in that family. It was introduced introduced in the late 1980's. The series continued through the 2714 & 2715 which were among the last Tek manufactured spectrum analyzers.
The 490 series was also made as an RF range product [without the microwave bands], initially in the 496 and then the 495. The 495 has the advanced features [synthesized, etc.] of the later 492A/B/PGM & 494 units. This makes a great unit for the two-way tech.
There were also a 2750 series of rack width lab analyzers based on the 490 architecture with expanded front panels.
The high point of Tek's spectrum analyzer products is the 2780 series produced in the 1990's. They offered liquid crystal color display, calibration to 1.2THz, and are the only analyzers I am aware of that allow simultaneous display of analog and digital traces. These are highly prized for TSCM work and still bring real money [not a surprise since they cost on the order of $70K new and have features comparable to high end analyzers even today]