Huuuuge lot of test gear, should I nab it?

[G0HZU]

How do you know I won't end up building a rf anechoic chamber and making use of the massive antennas for immunity testing?

Not many people would use a huge/long/narrowband/uncalibrated ham radio (yagi) antenna for immunity testing in an anechoic chamber.

[joshhunsaker]

I hear you... BUT... test equipment does age. Switches wear out, electrolytics go bad and many pieces of equipment use exotic parts as well. I got burned a few times with equipment which was impossible to repair.  Last year I bought a couple of HP power supplies from the early 80's. These needed all the electrolytics and front potmeters replaced. Good power supplies but they ended up costing twice as much because of the replacement parts. Not to mention the time spend.

As a rule of thumb I don't buy equipment which is over 15 years old (the HP supplies looked newer to me but I forgot how old I have become).

You're spot on, my Wavetek 141 purchase didn't work out so well (have that detailed in another thread here)... but honestly that's been one of maybe 20 used older pieces of gear that are still running awesome I've acquired recently and have put up with way more abuse than a newer, more fragile equivalent piece of kit would.  Plus, I can still attempt a repair on the Wavetek.  I've got boatloads of reels of components (axial and SMD) and I'm quite handy with a solder iron at this point (no problem doing 0603's without any kind of magnification).  To me it's a great learning experience and a good excuse.

Honestly, in my experience... it's funny because I've had just as much new gear die and/or malfunction on me than very old stuff.  At least with the older equipment it's less of a surprise.

Not many people would use a huge/long/narrowband/uncalibrated ham radio (yagi) antenna for immunity testing in an anechoic chamber.

"Biconical (or "bicon") antennas are often used in electromagnetic interference (EMI) testing either for immunity testing, or emissions testing. While the bicon is very broadband, it exhibits poor efficiency at low frequencies, resulting in low field strengths when compared to the input power. Log periodic dipole arrays, Yagi-Uda antennas, and reverberation chambers have shown to achieve much higher field strengths for the power input than a simple biconical antenna in an anechoic chamber."

http://en.wikipedia.org/wiki/Biconical_antenna

[G0HZU]

Log periodic dipole arrays, Yagi-Uda antennas, and reverberation chambers have shown to achieve much higher field strengths for the power input than a simple biconical antenna in an anechoic chamber.

Sure, they might use (a formally calibrated) yagi or log periodic antenna that has a few elements that is designed for relatively broadband use. But not many people will use a typical 10 element narrowband ham radio yagi for immunity testing. i.e. something 12 foot long optimised for a tiny bandwidth of maybe 144-148MHz.

[joshhunsaker]

Sure, they might use (a formally calibrated) yagi or log periodic amtenna that has a few elements that is designed for relatively broadband use. But not many people will use a typical 10 element narrowband ham radio yagi for immunity testing. i.e. something 12 foot long optimised for a tiny bandwidth of maybe 144-148MHz.

If the antennas are only yagi's or narrow-band then, sure... would end up being a bad example.  I dunno exactly what he has per say antenna-wise, I figured it might span a relatively good gamut, but maybe not.

[vk6zgo]

The big advantage of DSOs is their storage capability

No. The big advantage of DSOs, aside from their storage capabilities, is their capability to analyze and process signal parameters.

With an analog scope, all you get is what you see. For many complex signals this simply isn't good enough.

Ever try to look at an analog video field signal with any inexpensive DSO?
Many people use Oscilloscopes to track faults in equipment,where "processing of signal parameters"is not of high priority.
Being able to determine the electrical integrity of the signal is the important thing in that case.

An old 54645d or anyone of the megazooms can do that perfectly fine. You select pal or ntsc and can even dial in the exact line you want to see... Try that with analog junk. And these digital machines are 25 years old ! The screen refresh and acquisition refresh of these machines is fast enough they can update at the video framerate.

You didn't understand my comment.
Almost anything can look at a line rate signal,& it isn't all that hard to find an individual line with a 7000 series analog---a bit messy,but doable.

I've tried to look at the whole field at around 5mS/div with that generation of DSOs.
Their sample rate reduces so low that aliasing due to the presence of frequency components of up to 5MHz makes the display unusable.

OK,analog video is obsolete,but people still have to look at Mains hum on a pulse train from time to time.

[EEVblog]

Most of the stuff there is obsolete and a waste of space even if it's working. You'd have a better/easier/simpler future if you simply flushed the $2900 down the toilet and stayed away from this sale.

The thing here is what value (both technical & fun) you could get with $2900 in comparison.
I think that money would buy a ton of useful stuff on ebay, and you'd have IMO a good lot of fun searching for and bidding on dozens of items.
Rather than have it all served up to you in one big dumpster pile of who knows what.
You could get say 10 quality items of an average of $290 each, and that $290 goes a fair way in the 2nd hand market.

I for one wouldn't begrudge you for getting this, but I think more fun and better value is to be had elsewhere.

[vk6zgo]

If I remember rightly,this came up on QRZ.com a few years back,but got no takers.

Even WA6MHZ,the resident "packrat" didn't bite.
Of course,Pat already has a huge shed full of vintage gear at his own place.

It seems that the vendor still has the trailer part of the semi-trailer at his place---- if he threw it in as well, you could maybe get most of your $2900 back on that,& the Electronics would be a bonusl

[Wuerstchenhund]

Ever try to look at an analog video field signal with any inexpensive DSO?

Yes, actually I did, with a Siglent SDS1102CNL (probably as cheap as it gets). Not a problem.

Many people use Oscilloscopes to track faults in equipment,where "processing of signal parameters"is not of high priority.
Being able to determine the electrical integrity of the signal is the important thing in that case.

If you mean by 'determine the electrical integrity' that you're looking a a signal of limited complexity to determine if it's what it should be then yes, you can do that as well with a decent DSO.

[Wuerstchenhund]

Almost anything can look at a line rate signal,& it isn't all that hard to find an individual line with a 7000 series analog---a bit messy,but doable.

I've tried to look at the whole field at around 5mS/div with that generation of DSOs.
Their sample rate reduces so low that aliasing due to the presence of frequency components of up to 5MHz makes the display unusable.

When I did some work with video equipment a very long time ago, where we checked whole fields CCIR video with DSOs (we had some Philips PM3320A and later got some HP54510As), not much of a problem. We also had some analog Tek scopes but they were mostly sitting on the shelf waiting to sent away for annual calibration.

I'm also not sure what you're talking about re low sample rate as at that time high sample rate scopes were already available (the HP came out around 1991 and had 1GS/s). But CCIR video wasn't even a problem with the Philips which only had 250MS/s and came out around 1989 I think.

[nctnico]

I've tried to look at the whole field at around 5mS/div with that generation of DSOs.
Their sample rate reduces so low that aliasing due to the presence of frequency components of up to 5MHz makes the display unusable.

OK,analog video is obsolete,but people still have to look at Mains hum on a pulse train from time to time.

For that purpose a lot of DSOs have peak detect or a long memory compressed into one screen. You could have run into one which didn't have peak-detect (or didn't enable it) and/or long memory (or didn't enable it).

[vk6zgo]

A standard test in Television Broadcasting is to display one or more complete fields,& look for deformation of blanking over the full 20 (or more usually,40) mS.

Two things are normally checked:

(1) Hum at Mains rate,or twice Mains rate, (50Hz & 100 Hz in Australia).
(2) Clamp pulse breakthrough---Keyed clampers sometimes have problems with the pre & post equalising pulses of the Field Sync pulse.
This manifests itself as a "warping" of the blanking level.

Back in the early1990s HP & Tektronix would come to our TV Station,showing off their latest DSOs.
They would give us their "spiel",show us a few line rate signals,then we would ask them to repeat the above test.
They universally failed,because when they were displaying a signal 20 mS wide,their sample rate was reduced below the higher,& in some cases mid-frequency components of the video signal,causing aliasing problems.
They had to do this due to lack of memory in the instrument.
In the worst case,the sampling rate was lower in frequency than line rate.

I have seen quite a few screenshots of field rate video on  more modern inexpensive DSOs,in which it would be impossible to perform  test (1) or (2).

[vk6zgo]

I've tried to look at the whole field at around 5mS/div with that generation of DSOs.
Their sample rate reduces so low that aliasing due to the presence of frequency components of up to 5MHz makes the display unusable.

OK,analog video is obsolete,but people still have to look at Mains hum on a pulse train from time to time.

For that purpose a lot of DSOs have peak detect or a long memory compressed into one screen. You could have run into one which didn't have peak-detect (or didn't enable it) and/or long memory (or didn't enable it).

Maybe for hum,on a fixed amplitude pulse train,so I will give you that.

These tests were dynamic ones,done without interrupting the video signal,so video program material would be continuously changing the peak to peak amplitude of the signal.

We also looked for "Clamp pulse breakthrough"(see my previous posting).
It was commonplace to adjust clamping real time for minimum breakthrough,so I doubt these refinements would have helped.

I should have said that myself & several other TV Station Technical folk,as well as HP & Tek representatives tried,with the same result,so they should have known a way to make it work.
Remember,though, these were fairly early DSOs.

Now we have taken the thread thoroughly off topic,we will probably be chastised by the Moderators!

[jucole]

Show me a quality logic analyzer that offers as many channels of 100mhz analysis as my HP 1650A that doesn't suck for under $100

does my 1661AS count? :-)   no, but seriously I could have loads of fun on Ebay with the same money,  I could have bought that HP  18 times over and still have enough left over to buy my 6.5 digit solartron 7150, and have it calibrated.

[nctnico]

I've tried to look at the whole field at around 5mS/div with that generation of DSOs.
Their sample rate reduces so low that aliasing due to the presence of frequency components of up to 5MHz makes the display unusable.

OK,analog video is obsolete,but people still have to look at Mains hum on a pulse train from time to time.

For that purpose a lot of DSOs have peak detect or a long memory compressed into one screen. You could have run into one which didn't have peak-detect (or didn't enable it) and/or long memory (or didn't enable it).

Maybe for hum,on a fixed amplitude pulse train,so I will give you that.

These tests were dynamic ones,done without interrupting the video signal,so video program material would be continuously changing the peak to peak amplitude of the signal.

We also looked for "Clamp pulse breakthrough"(see my previous posting).
It was commonplace to adjust clamping real time for minimum breakthrough,so I doubt these refinements would have helped.

I should have said that myself & several other TV Station Technical folk,as well as HP & Tek representatives tried,with the same result,so they should have known a way to make it work.

IMHO a Tektronix TDS500 or TDS700 series scope (early 90's) should have no problem with your test. But these might have been outside the budget or the HP & Tek representatives may not have had full training. I've been to NZ once and the techs over there complained they never got good training for equipment they bought in Europe or the US.