Test Equipment

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James Bruce Bossie:
Tenma seems to make some good and inexpensive  general purpose test equipment. I am considering purchasing some to use for getting back into homebrewing after some years away from it.

Anyone have any experience with Tenma products? Scopes, and generators are in my mind.

Bruce W7JBB

Steve Katz:
As far as I know, Tenma doesn't actually manufacture anything; they are a distributor of many types of products including function generators, scopes, cable TV testers etc.  I've used some of their branded stuff over the years and it's "okay," but surely not "lab quality."  Kind of reminds me of "B&K Precision" gear, and similar stuff.

I'd much prefer used professional gear from Tektronix, HP/Agilent, Rohde & Schwartz, et al.  Cheaper, very available, better built, higher performance.  I can pick up a used Tek 150 MHz 4" scope any day of the week at a local garage sale for $200 or so, with carrying case, manual and probes and it will run rings around a $459 Tenma 20 MHz scope in every respect I can think of.   Ditto for signal generators from HP, Boonton, et al.  I see old 8640B's for $200 or so: 500 kHz to 540 MHz, precise calibration to +/- 0.5 dB from -140 dBm to +13 dBm, frequency accuracy of 10 Hz or 0.5 ppm, AM, FM and pulse modulation with low distortion.  Tenma has nothing like this at any price.

For a home lab, I insist on a low-distortion audio generator like a 200CD; another high performance signal generator like an 8640B; a lab quality 150-200 MHz scope like several Tek models; a precision bench supply adjustable 0-100 Vdc or so; a differential AC VTVM like a Ballantine or Fluke; a spectrum analyzer like an old 141T frame with 1200 MHz plug-in and an I.F. section with good filtering, and preferably the tracking generator; a G-R Admittance Bridge or equivalent; a good wideband 20 dB dual directional coupler; an high quality RF millivoltmeter (Boonton 92AD or similar) or RF microwattmeter (Boonton 42AD or HP equivalent); stuff like that -- which can all be purchased in good condition right now, today, for a grand total of about $1500-2000.  For everything.

I absolutely, positively do *not* buy this stuff from eBay sellers, no matter what their feedback rating is.  I have never once been satisfied with a test equipment purchase via eBay.  I find local deals via the Recycler and other local resources, go inspect and try out the gear, and then pick it up.


Clark McDonald:
I discovered Tenma products as a good pricepoint alternative back in the early 80s when keeping the tools and instruments on the test benches in my old repair facility was always an issue.  

I have found their products to be very serviceable, accurate and a good deal.  

The Tenma temperature controlled soldering station is now my first choice when setting up a new facility.  

Their DMMs can compete with meters costing orders of magnitude more, too.  

I typically buy them through mcmelectronics.com and have had great dealer service from them over the years, too.  

There was once a young fellow whom I hired who was very proud of his Fluke meter, didn't realize that I have a few of them at home and one in my desk but was using the Tenmas out in the shop everywhere.  Well, you probably know where this story is heading, he tried his best to prove that the Fluke was going to be more accurate and more precise, etc. -- and couldn't do it!  Besides that, I kept trying to tell him that we were a warranty repair shop and not a NIST traceable laboratory or the like.  If I need NIST trace I don't even reach for the Fluke, I reach for one of my Keithley meters.  

The Tenma meters seem to be knockoffs of Fluke technology anyway, typically from past models.  

I don't think you will be missing a thing by specifying Tenma test equipment for your needs.  

In all these years the only Tenma DMM that failed was the one in which the yound lady attempted to measure the resistance of the AC socket.  (!)  -- And I was able to repair it and place it back into service by reparing the burnt PCB board trace and replacing the internal fuse.  


Clark McDonald:
"A knowledgeable technician with a good DMM or Vacuum Tube Voltmeter can out-troubleshoot many less knowledgeable techs that have a full bench of gear at their disposal."  

That is what I used to teach at the community college and it is indeed a fundamental truth.  


James Bruce Bossie:

Thanks for the reply. I have had the same experience that you have had. Anymore, unlike the old days, one can do a lot with a good DMM.

I am only home brewing HF QRP type items and for those general purposes good reliable test is all that is necessary.

I stopped building for a few years and lost track of the good item numbers and manufactures that are out there today.

I really do appreciate your input as it confirms my suspicions.



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