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@mike this can be something for you  ... as i remember you once struggeld with the Hold-Off menu on the RTB2000

Didn't struggle, just that it was too far down the menu so you had to scroll to reach it
Truly this is an incurable disease.

I don't think the thread would've lasted so long if it was curable. :-DD
True, unlike smoking, there is no patch available, other than the one you're looking for to cure that dammed software bug in your latest piece of processor driven crap equipment  :-DD
RF, Microwave, HAM Radio / Re: Breadboarding at RF
« Last post by Kalvin on Today at 05:51:26 AM »
My guess is that you are seeing reflections due to mismatch with the filter, coax and the oscilloscope's input impedance. The impedance of your filter should match with the coax, and the input impedance on the oscilloscope should match with the coax.

The signal source is 50 Ohm, as are  the cables.  There's a 50 Ohm through-terminator on the scope input.  Obviously when it went to the breadboard, that wasn't any particular impedance - it's just bits of random wire and the breadboard itself.

I'm not sure what you mean by impedance of the filter - it's just a simple RC lowpass filter - 22k series resistor and a .1uF parallel capacitor.  How would one match impedance on that?

Typically the RF filters are designed for specific impedances for the best performance. If the impedance of the source feeding the filter input and/or the impedance of the filter output do not match with the load, the filter response may not be as intended.

It looks that you have terminated the coax properly at the oscilloscope's end, so there should not be any reflections. So, my guess was wrong :)
On a separate note. I have both the Rigol 1054z and the Siglent 1202x-e in my cart over at Amazon. Been trying to figure out which one I am going to buy. I like the 200Mhz and the increased color depth of the Siglent but I really do like the 4 channels and logic decoding of the Rigol not to mention what seems like more polished software.

It's a tough choice. I'm kinda waiting around to see if I can get that discount coupon for EEVBlog members. I think that might be enough to push me over the edge for the Rigol. It will give me enough bargaining power to keep me out of the dog house when the CFO  (MY wife)  :rant:  :blah: :rant:  finds out that I bought more test gear.       
Have a good look at the new 4ch X-E first.

There's a discount thread to get Siglent equipment from Saelig, ask for the code there.
Metrology / Capacitor to replace C8 on 3458A A6 board - Outguard PSU
« Last post by perdrix on Today at 05:42:19 AM »
This is a 53D capacitor, 8300uF (-10% +75%), 35V.  The original was 85C, the current version is 105C (53D832G035JP6E3).

Sadly though this doesn't appear to be available in UK (except with a £15.95 surcharge for shipping from Newark to UK Farnell) which effectively doubles the price.

Can anyone suggest a suitable axial alternative and source in UK.

In conjunction with the announcement of the new scopes, it looks like they have also released the new User Manual for the RTB2000 that goes with FW 0200. I haven't looked at the changes yet. They also have a new "Getting Started" guide for some reason.
Renewable Energy / Re: UK solar doldrums
« Last post by nfmax on Today at 05:38:48 AM »
I will say that is (in the language of my 3 year old) "10 times awesome". It's rare to see such a large amount of data presented in a format that makes the intended view so obvious. It really is 10 times awesome.

Aww, thanks! This kind of data presentation, and wrangling the raw outputs from sensors into something presentable, is more or less what I do for a living these days. I used to be an electronics engineer...
RF, Microwave, HAM Radio / HDSDR, RTL-SDR, and power
« Last post by jgalak on Today at 05:37:14 AM »
I have an RTL-SDR dongle hooked up to HDSDR.  The spectrum display shows decibels of power on the signal.  I understand they aren't calibrated, but is there any information on what they are relative to?  It doesn't seem to be dBm.

I ask because I'm trying to look at a signal that, on the scope, shows as 1.8Vpp (but not centered on ground, rather 0-1.8V)  Which should be about 9dBm.  On the HDSDR it's coming in around -50dB.  (the signal is 50 Ohm source and it's fed to the dongle via a 50-75Ohm adapter, since the dongle is 75 Ohm).  Admittedly, it's an ugly square wave, so lots of the power could be in the various harmonics its throwing (and it's throwing a lot of them), but that much?

I don't have any other way to measure power that low at those frequencies - my power meter can only resolve down to about .1 Watts - 20 dBm. 
I'd bet they are trying a new 'marketing' ploy, re-branding lines with different names to set them apart from the typical low end 'stuff' they have been carrying.

It's very apparent with hand held power tools, drills especially.  ;)

Since Harbor Freight is in almost every town, it'd be nice if they offered an upgraded line of tools you could count on for quality; their tools can be pretty hit-or-miss as things currently stand.  I used to know that I could drop by Sears and buy a Craftsman tool and get something of decent quality.  But the nearest remaining Sears store is now 40 miles away, and Craftsman is not what it used to be...

[These days, the best nationwide store for tools of known quality may be Home Depot.  But HF can often be found in even smaller towns]
Test Equipment / Re: Siglent SDG6000X series 200-500 MHz AWG's
« Last post by JohnG on Today at 05:35:08 AM »
Has anyone else had any experience with one of these? I have an SDG2042X, but am likely to need both higher frequency operation and faster rise/fall times.

Also, wondering if it has essentially the same command set as the SDG2000x series, since I have some ATE software that presently controls the SDG2042x and would like to avoid changing it.

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