Get a Fluke DMM

[anatech]

Hi OzMikeH,

Have a look at the accuracy of a fluke hand held, they aren't that great. only 2% usually.

I remember them as being somewhat better than that. I did tons of them and there is no way an Extech or other meter would stay within the limits of a Fluke. They were actually superior to many bench meters (excluding Datron, Fluke, HP/Agilent and Kiethley). Their attenuator is also much, much more accurate than other meters. Then there is the question of high frequency accuracy. They really shine there too. I'm talking about 85/87's and like models. They do make cheaper meters with relaxed specs, but their good ones are even better.

Another huge bonus. Unlike most other meters on the market (bench or otherwise), a Fluke will hold it's calibration extremely well. That is unless you so something evil to it.

never ever use the locking probes

Well, yeah! Those terminal blocks are not cheap either. Clean with alcohol, nothing else.

1 hour labour minimum charge from a calibration lab to check it and print out a report that says it complied with manufacturers specs.

No. Humans being what they are, and the fact that these hold their calibration well, make sure you get the cert with recorded values (all of them!), before and after. This is an R6 level at Transcat. Keep them honest or you may as well just burn the lower amount of cash. A C of C (certificate of Compliance) is a complete joke. This says that it's a meter and it works. Yipee!

A brilliant meter, but not able to be used to it's full potential because it takes 2 hours and some seriously exotic gear to calibrate the damn thing.

Yes. A Fluke 5500A, or better yet, a Fluke 5520A. The 5500A is getting dicey. Still, my HP is the very best item I ever bought. What they don't tell you are all the features you get beyond the basic ones. No way I'd trade mine for a pair of Fluke 87 equiv's, because that is what mine is currently worth new (still current). Not even 4 Fluke meters.

A second hand Fluke is a better buy than a brand new no-name meter.

Pretty hard to argue that point. Although Steve's meter may possibly give them a run for their money. Far more functions in Steve's also. He can trend bias over time for example. I can if I hook up the GPIB and program it. The newer Agilent meters are going USB and LAN. You have to love a LAN connection. Fantastic!!

BTW, there are devices that will give a serial port an IP address and communicate as if it's hooked up to your computer! Cool!

-Chris

[OzMikeH]

Serial-IP is a program I use a lot, Then we stick Lantronix boxes on everything that has a serial port. Great for offsite access to serial devices.

One weird thing I had with the HP974A that really put me off it:

I was load testing a static inverter (28VDC to 110V 400Hz AC for aircraft)
We test the static inverters by running them through a big variac into a 2400W 240V electric kettle. We monitor voltage, current and waveform between the inverter and variac with 2 calibrated multimeters and an analog CRO. We use the variac to vary the load on the inverter for various tests.
The HP was indicating 2.16 amps at no load, then I UNPLUGGED the kettle and the reading didn't change, 2.16 amps into thin air. The meters on the DC supply were showing the normal idle current for the inverter. The waveform was a nice sine wave without any ugly fluffies on it but somehow measuring current on an open circuit with this signal applied was freaking the meter out.

[anatech]

Hi OzMikeH,
Serial to IP is fantastic. New life for heritage stuff that still works great.

Some Agilent / HP stuff has very wide bandwidth and high input impedance. I can see where this may cause problems in some cases.

Have you given Agilent a call? They have engineers to sort these things out and they are very approachable. Either that or the calibration is not being done correctly. Either way you ought to find out what the issues are.

-Chris

[imix500]

Just had to post because I've been using one the past few days...

Somewhat related- Fluke Network meters are fantastic too.
The Cable IQ meter is very popular at work for checking CAT 5/6 as well as simple network troubleshooting- but mostly testing cable as it's used more and more for audio and video over UTP.
Fantastic!

[anatech]

Hi imix500,
I'm looking forward to music over network. My house is ready in every single room. Plus a run of CAT-3 to every room.

Then there is a pull string I left to each location.

-Chris

[imix500]

Indeed. Aviom has been using it for years with great success. With the new AES-50 standard, anythings possible. Our new Midas XL8's use that all over the place. Cool stuff.

[anatech]

Hi imix500,
Beats the heck out of a snake! With more security and adaptive frequencies, you could go wireless. Risky in some cities.

-Chris

[imix500]

Absolutely. Although the XL8 sends control to the DSP brains via Fiber on Neutrik's awesome new FiberCon connectors.

I've sent 32 channels of audio 1000' over two cat5 cables with Aviom. It spoils one quickly.

Wireless would be cool and is probably on the way, but here in the states bandwidth is quickly running out. In NYC, finding clear frequencies for a few dozen wireless mics is really challenging.

[anatech]

Hi imix500,

I've sent 32 channels of audio 1000' over two cat5 cables with Aviom. It spoils one quickly.

Absolutely. I've being doing similar things with VoIP. What we really should have are standards equal for both. They do send audio over VoIP already for retransmission.

Wireless would be cool and is probably on the way, but here in the states bandwidth is quickly running out. In NYC, finding clear frequencies for a few dozen wireless mics is really challenging.

Actually, all you are sending is data. Many wireless nodes are self adapting. Or a band could be cleared for this use. Individual mics would simply be the same thing converted to digital. There can be problems, but this would eliminate standard static. We'll trade static for digital noise.

-Chris

[imix500]

Hopefully, standards will multiply in the next few years. AES50 is the newest that is of use to guys like me on a daily basis, and it looks like manufacturers are scooping it up. Otherwise, it seems like everyone has thier own protocol.

I belive high end wireless audio is heading in this direction, but few manufacturers have been successful with a digital system. One that I used on a show and works pretty well is made by Trantec.

The idea of systems adapting and selecting their own frequencies in a live situation is very scary to theater sound types. We usually have a dedicated computer and KVM system just to monitor each channels RF and AF remotely.
Still, once all-digital works and is proven it will make our lives sooo much easier.