| General > General Technical Chat |
| Older, second hand spectrum analyzers, HP-8562A and Tektronix 2712 |
| << < (3/6) > >> |
| tecman:
Either unit is a good find. The HP has a wider range, but the TEK is a respectable unit as well. You don't need probes to test. Hook a 6 foot piece of wire to the input. Set the span and yopu should be able to see FM or AM radio stations with the sensitivity cranked up. Higher range look for cell phone or UHF TV. paul |
| gregariz:
The 8562A is an excellent Spec-An. This is an earlier model but you will see them commonly used in industry. You didnt mention the price but if you are ebaying it I would suggest perhaps the 90E series as these were made until very recently and prices seem to be similiar for the 60 series. The 90E series has the advantage of 'personality' cards you can turn your instrument into several others ie Network analyzer, Noise analyzer etc. Depends on what you need, but the 60 is an excellent Spec-An so you cant go wrong. |
| joelby:
I finally had a chance to photograph the TR4131 around 0 MHz. The calibration signal was connected in both. The first attachment is centred at zero (note that the calibration is 2.5 MHz off shortly after power on). The second attachment is centred on the calibration signal's fundamental frequency. Fortunately it doesn't look like it has the 1st mixer problem you described, Aurora. Pity about the frequency stability, though! Maybe it would be possible to replace a few of the internal reference oscillators with newer or higher precision parts? :) Has anyone had any luck with the GPIB interface? Photographing CRTs is lousy, so I was thinking about designing and building a USB-GPIB interface to download the data. It will probably be a much better use of my time to just buy a cheap one! |
| Fraser:
The 1st Mixer appears fine from those pictures :) just remember not to go into the 0dB attenuation mode unless you are certain that the front end will not be exposed to ESD or other high potentials. Never connect it directly to an 'open' aerial such as a discone without adequate front end protection. I managed to get hold of an ICS USB to GPIB interface that works with the TR/R4131. Sadly I am having problems getting the 'GPIB toolkit' software to 'talk' with the unit. I need to revisit this again some time but haven't had time recently. http://www.ke5fx.com/gpib/readme.htm The '7470' plotter emulator should work with the 4131 but I believe I am having an issue with the ICS interface rather than the software or analyzer. If you use an NI PCT GBIP card life will be a lot simpler as even the NI USB interfaces can be a tad temperamental. The Prologix GPIB interface is also another more affordable option. http://www.cliftonlaboratories.com/ezgpib_and_prologix_gpib_adapter.htm The frequency error that you showed in the first image is typical of the TR4131 at power on, I remember it well. It will not 'self zero' so you must do a self calibrate / zero cal. The solution is a 30 minute warm up followed by regular self calibration. The unit should settle quite well after warm up. I will dig out the manual as promised and look at the specified stability figures for you. |
| joelby:
Thanks for the mixer confirmation! I'll look after it :) The software you linked to looks great. I've ordered a Softmark USB-GPIB adaptor for $60 and will let you know if I can get it working. The command set is well documented, so it should be pretty easy to knock something up with gnuplot. I've got the English R4131 service manual, which seems to be operationally identical to my TR4131, and the Japanese TR4131 operating manual, which sadly lacks service information and schematics. I suppose that it'd be reasonably straightforward to crack it open, identify all of the oscillators, check their stability against a good signal generator, then replace them if necessary, but it also seems like a shame to ruin an otherwise perfectly good and rather expensive piece of test equipment! Both manuals were found at http://www.advantest.co.jp/products/emi/end_of_sale/manual/en-index_en.shtml and http://www.advantest.co.jp/products/emi/end_of_sale/manual/en-index_jp.shtml |
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