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Per Vices Noctar Woes

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#1
Hello, I've been lurking around this forum for a while but this is my first post. As such, I'll give a brief background:

I began to collect some screenshots and write up an easy-to-read guide, aimed primarily at hams and others who are new to SDR (like me) who may have been considering the Noctar but were put off by all the hoops, Per Vices' non-existent literature for the beginner, non-existent notoriety and general lack of support. This guide and review would have been my first post here on RadioReference since I don't have a blog or any way to get this stuff out.

I disregarded my gut and ordered the Noctar card from Per Vices about two months ago. The primary goal was to try and ease continuing development of a system my father had been creating for a few years before he became ill. At the moment, it's an unwieldy rat's nest of bread boards, wires, etc but works well and is very likely patent-worthy (the concept, that is). For the past 2 years I've been considering the possibility of porting some or most of the bulk of IC's and discreet signal processing components to the software domain but dreaded learning new programming languages, programming FPGAs, etc. It's bad enough having to decipher my dad's work on paper and trace wires, part numbers and all. Then there's the underlying math...

I had my eye on ordering 3 or 4 USRPs but the price tag put me off especially after taking into consideration the extra cost of daughter boards. After much consideration, I figured out a way to potentially attack this problem one chunk at a time. I decided to order the Noctar as a means to get my 'foot in the door' with Linux, gnuradio, Python/C++ and software DSP in general. I also bought a desktop PC with Intel Core i7 and 32MB ram which the card would call home. For reference, the total cost would have covered a USRP N210 (without daughterboard).The card arrived after about a week (from Canada) and by that time, I'd already set up the Linux box and had all the software installed.

Physical installation was pretty straight forward. The drivers were installed without too much of my hair being pulled out (keep in mind, I'm a new face in the Linux world). After quite a bit of tinkering with gnuradio/GRC and writing the noctar through the SPI, I began to gain some momentum.

Just as I began to get my feet wet with phase 1 of the project, the Noctar's hardware DSP went KAPUT! It took me 2 days to zero in on the problem. That's about the time reality hit home and it really sunk in when emails have gone unanswered for several days. To clarify, the card still outputs samples at full rate. The hardware DSP handles the bulk of down-sampling to a rate which doesn't tax the host computer so much. There are times when a high sample rate is useful but it's nearly impossible to do any real-time signal processing in software when so much of the system's resources are used to down-sample the stream. At the Noctar's full 250MS/S, aliasing is horrible and data becomes corrupted so half the samples MUST be dumped in order to maintain signal integrity. That means the maximum effective sample rate is actually 125MS/S, not 250 like Per Vices advertises. In short, without hardware DSP, the crippled Noctar is useless for my purposes!

Email replies were very prompt when it came to making the sale and little problems that sprung up which I needed help with. Now that the card is malfunctioning and after about a week, I think it's safe to say they're blowing me off and this project is once again stagnant.

Bottom line:

The Noctar is a great concept muddied by poor planning, design and foresight. If you're thinking about embarking on serious SDR, look elsewhere. By now, I would've been chipping away at my project with a USRP and WBX daughterboard but I got tripped up trying to save some money. I'm not a university or corporation! It may be for the better; Ettus has announced some exciting new products they plan to bring to the market soon. There are other small companies entering the scene as well such as Nuand.

Purely Speculation (based on the limited information I have):

The card most likely overheated in spite of providing extra ventilation and installing an extra (optional) fan. For comparison, my graphics card has a heat sink that's bigger than the card, itself. If you look at the Noctar, well, you get the point. This product will probably be swept under the rug like the Phi. PV doesn't even refer to it by name on their website. They call it their 'previous product'.

I'll report back if Per Vices contacts me with anything other than a 'sincere apology'.

Thanks for reading my rant,

Tom
 

foxtail

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#2
With a review like this and all the folks on this site that would read this...I'll assume that no one will be buying from them anytime soon! Sorry to hear about your luck, all the best and let us know how it turns out.
 
Joined
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#3
Quick update:

I've been further troubleshooting the Noctar and have received a reply from Laura of Per Vices who indicated I might need to reflash the FPGA firmare. I ordered a USB blaster and will report the results when concluded. I hope I can revive the dead Noctar and resume work on my project.

Tom
 
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#5
I'm still following...I like the concept of the device, as long as it works. Keep us informed.
I managed to flash the firmware and very preliminary testing shows it's alive! The I/Q streams are flipped so I'm going to have to modify the firmware and reflash. Should be a relatively quick fix but in the meantime, I flipped the streams in software for the purpose of quick testing.

I'll re-flash and put the hardware through its paces over the weekend and if all goes well, I WON'T be troubleshooting the hardware for a good while to come. We'll see...
 
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#7
Any more reports on the progress of your unit? Thanks.
None yet. I'm leaving it as-is for now and swapping I/Q in software. I'm having some reliability issues, though. I have to reset the computer several times because it locks up after a few minutes of using the Noctar. Hard to say what's causing it at the moment...

foxtail - I have to ask, out of curiosity, are you affiliated with Per Vices?

T
 
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Messages
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Location
Texas
#9
(...) I'm waiting for the hackrf to hit the shelf.
I've had my eye on this as well but always gravitated more toward the BladeRF. Both show good signs of continuing development although my next purchase would probably be a newer-model USRP. At some point, I'm going to need a reliable system that just works. It's one thing to write DSP code and debug. It's an entirely different matter when your debugging is compounded with flimsy firmware, drivers, hardware, etc.

The HRF is open-source and is the least expensive in its class - last time I looked. It'll be interesting to watch these products mature with time (if there is serious ongoing development, of course).

T
 
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Feb 12, 2014
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#11
Without knowing much about the computer you purchased, I just wanted to say that it is possible that the motherboard could have a bottleneck issue since the card seems to push 8Gbps across the PCI-e bus. Many name-brand computers use cheap motherboards to cut down costs. Even though it says i7 and you got 32GB of RAM, you may not be able to use it to its full potential because of hardware limits.

Also found this in the Noctar user guide. hope its helpful:

"At full bandwidth (no decimation), some computers have trouble
running GNU Radio without dropping bytes, especially with
waterfall plots. This is a problem as we use 16 bit integer sizes. Dropping a byte (8 bits) irrevocably corrupts data. If you find
yourself encountering this problem, increase the decimation to 2 or
higher will avoid this problem."
 
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#12
I replied in the other thread with this info. I am sympathetic to the frustrations, and there are indeed flaws in the product. These frustrations are compounded by the difficulties of being a small company with limited resources.

Definitely not a card for the faint of heart ;) but exceptional once tamed...

---

I have personally used multiple Noctar cards and one of the older Phi cards. They have worked great, and I look forward to the new line of radios.

That said, they put off a ton of heat and have inadequate cooling. You MUST compensate for this if using for any non-trivial lengths of time. I hope more dissipation is built into future versions of this hardware.

The other major problem is the kernel drivers on Linux. It does not efficiently communicate with the HW over PCIe spinning a single core to saturation for each tx / rx path. Reduce sample rate if you’re not running a top of the line processor with at least 4 physical cores per radio. (otherwise, you _will_ have to tune for some workloads)

I feel like this card is in same situation as the original PlayStation 3 launch. The cell processor was such a new architecture and technique that it took a while for developers to really make use of all its capability.

The Noctar radios cover huge band at awesome sample rates and transmit too. They are worth the price at even the screwed-by-upstream-suppliers price point, and I am continually impressed by the power of these devices.

TL;DR: you MUST compensate for some design shortcomings; resulting SDR setup is high performance, exceptionally low latency, useful for a wide range of purposes.

---

P.P.S. There were some mailing list threads about using GPU offload for more processing on full rate wideband sources. The frustrations above describing problems dealing with 250Ms/sec are recurring potentially well addressed by an on-board GPU.
 
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#13
... increase the decimation to 2 or higher will avoid this problem."
Increasing the decimation to 2 will halve the sample rate which the original poster wanted to avoid. But I can confirm this does resolve the problem on less than high performance processors/systems.
 
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#14
The other major problem is the kernel drivers on Linux. It does not efficiently communicate with the HW over PCIe spinning a single core to saturation for each tx / rx path. Reduce sample rate if you’re not running a top of the line processor with at least 4 physical cores per radio. (otherwise, you _will_ have to tune for some workloads)
I tend to agree although I have no control over that. Ironically, I disabled hyperthreading in bios which resulted in a performance and stability boost. This forces 4 physical cores rather than 8 virtual. This leads me to believe that:

1. There is significant overhead involved in running 2 threads per CPU core
or
2. The OS and/or GR aren't optimized for the same.

All of this carries a steep learning curve and as much as I wanted to avoid it, I'm going to have to chip away at it little by little. Now I understand why the Ham Radio Science fellow stopped at unboxing the Noctar! I bet he would've been ticked off if he had to pay for his. Just sayin'.....
 
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#15
... Definitely not a card for the faint of heart ;) but exceptional once tamed, ...
Have you modified the Noctar's firmware or have any experience with Quartus II? I have a copy of the Noctar firmware files but the collection is pretty unwieldy. I'm looking through the various files and trying to piece this stuff together.
 
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Aug 29, 2014
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#16
tomisius,

How is progress with the Noctar?

I'm considering purchasing a Noctar. I'm currently using a USRP B200. However, the USB 3.0 interface seems too unreliable at the higher TX+RX bandwidths I need. PCIe may be the answer.
 

foxtail

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#17
After all that you read in this dialog...."you did read this didn't you?"...you still want one of these cards? Having to cut down your pc cores for it to run right is not something you should have to do! That's like buying a corvette with a 4 cylinders engine...why. Anyways...good luck with your purchase.
 
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