TL;DR - Visual Analyzer, PC Sound Card Oscilloscope software. Nice spectrum analyzer. Worth checking out. http://www.sillanumsoft.org/prod01.htm
Through a really good YouTube Post on using an SDR for Frequency Deviation Measurement on FM transmitters I learned about Visual Analyzer. I should probably do a separate post just on this.
Previously I used Xoscope on Linux and Zeitnitz Soundcard Oscilloscope (http://www.zeitnitz.eu/scope_en).
I had also found, but not used Zelscope, Soundcard Oscilloscope and Spectrum Analyzer.
I originally got some pointers on sound card osclloscopes, from Virginia Tech's Introductory Electronics courses that were based on their Lab in a Box, so that students would have all of their own materials for doing the electronics work without having to be in a physical lab. See:
Virginia Tech, Experiment 12, Calibrating a Sound Card Oscilloscope
I only went so far with sound card oscilloscopes, because shortly after I started experimenting, the Rigol DS-1052E oscilloscope became available within my budget. I bought it for $400 direct from China. The Rigol caused a little bit of a revolution in terms of oscilloscope availability and pricing.
That was all back in 2009 and 2010 when I started reading a lot more about electronics. In December, 2009, I finally took the exams from my amateur radio license. I passed both Technician and General with 100% and went back for the Extra Class at the next exam session. I got one wrong on my Extra.
Of course, the interesting bit that got me here writing this today is that the RTL-SDR stick can be used as the analog (ok radio frequency) front end for a software oscilloscope, spectrum analyzer, deviation meter, etc. Especially for those of us without much in test equipment.
Notes on the various things I'm interested in. Well, interested enough to write and share some notes on.
Saturday, January 17, 2015
Monday, January 12, 2015
Intel Atom (Avoton) Mini-ITX (NAS) Server Build Notes
I'm building a mini-ITX NAS style server using Intel's low-power Atom server chip, known as Avoton. The highlights are 8 cores, 64 GB max memory, yet passively cooled, quiet and low power, 20W TDP.The system's idle power usage without spinning disks is only 14 Watts. This makes it ideal for a SOHO file server, NAS server, lab box, etc.
The system I'm assembling resembles iXsystem's FreeNAS mini. The main difference is that I went with the Supermicro motherboard instead of the ASRock motherboard. I'll compare the two motherboards later and/or in a separate blog post. However, I'll summarize my decision as The ASRock is better if you are going for a pure storage (NAS) box. I went with the Supermicro as a better general purpose system with USB 3.0 ports and 4 x GbE ports.
The summary is the Ablecom CS-M50, aka Superchassis 721TQ-250B is a very nice case with real hot swap drive support. The most detailed reviews are actually for the FreeNAS Mini. You can also find some reviews searching for the Ablecom CS-M50.
The one problem so far is that the front panel USB ports are USB 2.0. The A1SAi motherboard has header connectors for USB 3.0, which use a different style header connector. Currently, I've got no front panel USB ports. I've emailed Supermicro support.
The system I'm assembling resembles iXsystem's FreeNAS mini. The main difference is that I went with the Supermicro motherboard instead of the ASRock motherboard. I'll compare the two motherboards later and/or in a separate blog post. However, I'll summarize my decision as The ASRock is better if you are going for a pure storage (NAS) box. I went with the Supermicro as a better general purpose system with USB 3.0 ports and 4 x GbE ports.
Components:
- Supermicro AISAi-2750F Motherboard
- Supermicro Chassis and 250W Power supply 721TQ-250B
- 16 GB: 2 x 8 GB Crucial SO-DIMM with ECC
Case and Power Supply
One of the most difficult decisions was trying to find a good case and power supply. There is a lot of poorly designed cases. There aren't many reviews for mini-ITX NAS-style cases. Through the reviews that are available I found one good choice which is also the same case that iXsystems uses for the FreeNAS Mini, the Ablecom CS-M50. Unfortunately the Ablecom isn't sold in the US directly. It is primarily sold to OEMs in large quantities. I stumbled around for a while until a kind person clued me in that Supermicro sells the Ablecom CS-M50 as the Superchassis 721TQ-250B. It is even linked from the page for the A1SAi-2750F motherboard and I didn't notice it or assumed it would be yet another crap case.The summary is the Ablecom CS-M50, aka Superchassis 721TQ-250B is a very nice case with real hot swap drive support. The most detailed reviews are actually for the FreeNAS Mini. You can also find some reviews searching for the Ablecom CS-M50.
The one problem so far is that the front panel USB ports are USB 2.0. The A1SAi motherboard has header connectors for USB 3.0, which use a different style header connector. Currently, I've got no front panel USB ports. I've emailed Supermicro support.
Other People's Builds
Here are some of the sources that I used in making my decisions:- My FreeNAS Build with The Supermicro A1SAi-i2750f (reddit, billakay)
- /My FreeNAS Build with Supermicro A1SAi-2750F (FreeNAS Forum)
To Do
- Determine what combination of hypervisors and operating system
- Linux Host + VirtualBox
- Linux Host + KVM
- VMware ESXi
- FreeNAS native FreeBSD
- Solve Front Panel USB port connectivity problem:
- Ideally there is a board from Ablecom, Supermicro or someone else that will give me USB 3.0 front panel ports.
- Alternatively, an adapter cable that gives me USB 2.0 ports would be preferred.
Things I've Learned
- The Supermicro 721TQ-250B case is the same as the Ablecom CS-M50 and is available at retail in the US.
- The AST2400 IPMI BMC controller with fully integrated keyboard, video, and mouse, iKVM is very nice. I could have configured the system out of the box without ever attaching a monitor to.
- The Supermicro/AST default Username and Password for IPMI is UPPER CASE and CASE SENSITIVE. I mistakenly thought I couldn't access the BMC until I configured it through the BIOS. The whole problem was the the default username and password were both all upper case.
- As a result, the system is INSECURE out of the box. Change your IPMI/BMC username and password from the default as soon as possible.
- IPMIView from Supermicro/AST is pretty nice. It is a standalone Java Application. However the web browser interface is just as good or better for a single system.
- The BIOS watchdog feature causes the system to be reset every 5 minutes. Nothing is logged to the event log. Don't set it, at least until you understand how to use it. I think the Linux kernel is setting the hardware watchdog.
- An improperly seated SO-DIMM, caused the system to hang at BIOS POST, with the code B4. However there were no beeps and I couldn't find a description of text error codes. The manual only gives the beep codes.
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