New product from the Chinese, a Kiwi-thing + RPi

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New product from the Chinese, a Kiwi-thing + RPi

cathalferris
I was perusing the usual Chinese shopfront websites after John Seamons (KiwiSDR designer) was complaining about the existence of unlicensed clones of his design, when I came across something rather interesting:

https://www.aliexpress.com/item/4001289323087.html

It would appear that some enterprising engineer has developed the KiwiSDR hardware concept, and fitted it into a hat that mates appropriately with an RPi. It would appear that the engineer has used the KiwiSDR code and pushed it onto a 16bit ASIC and the RPi3b is the interface board. Utterly unknown if this device works..

I'm going to trial one of these as a WSPR reporter, see if the sensitivity is anything like the real Kiwis I have here. I'll have to rig up a better cooling system for the ASIC, >60 degrees does not look good, but that is within my engineering skillset.

Normally I'm quite averse to getting a clone, but this one does look like an improvement in ways over the original Kiwi. The form factor change and the plug-and-play interface to the Pi makes for a more compact and possibly much quieter solution. I also already have two Kiwis.

I also know well that there's zero support due from John on anything to do with this, given that the Pi branch is guaranteed to stay beta and I have no intention of using any of John's services that he provides to genuine Kiwis. It's as a curiosity for myself

From my own point of view, if this works as intended, I can do all of my WSPR listening and decoding on one device, with less noise and more self-contained. That would be a win.

I would happily paypal some monies to John if it does work as intended.
Cathal Ferris (EI4IWB)
Two standard KiwiSDRs listening to 14 bands of WSPR from an outdoor AAA-1d
Rob
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Re: New product from the Chinese, a Kiwi-thing + RPi

Rob
Holger Oe9GHV has installed one of those KiwiPis at his site and MERGed it with his KiwiBBs, and we now have a spot and noise comparison between them for almost24 hours.  

The RF inputs are identical, and Gwyn has created a Grafana page which charts some of the noise and SNR differences between them. 

If I am interpreting the graphs, the KiwiPi named KIWI_4 is 2-4 dB quieter than the KiwiBB KIWI_0 on 20M, and there is a corresponding 2-3 improvement on SNR reports.  If that is true, the KiwiPi is a major improvement in RF performance.

Email me at my personal address in the WD -h help screen and I'll send you links to Gwyn's pages.

On Sun, Sep 6, 2020 at 6:56 AM cathalferris [via wsprdaemon] <[hidden email]> wrote:
I was perusing the usual Chinese shopfront websites after John Seamons (KiwiSDR designer) was complaining about the existence of unlicensed clones of his design, when I came across something rather interesting:

https://www.aliexpress.com/item/4001289323087.html

It would appear that some enterprising engineer has developed the KiwiSDR hardware concept, and fitted it into a hat that mates appropriately with an RPi. It would appear that the engineer has used the KiwiSDR code and pushed it onto a 16bit ASIC and the RPi3b is the interface board. Utterly unknown if this device works..

I'm going to trial one of these as a WSPR reporter, see if the sensitivity is anything like the real Kiwis I have here. I'll have to rig up a better cooling system for the ASIC, >60 degrees does not look good, but that is within my engineering skillset.

Normally I'm quite averse to getting a clone, but this one does look like an improvement in ways over the original Kiwi. The form factor change and the plug-and-play interface to the Pi makes for a more compact and possibly much quieter solution. I also already have two Kiwis.

I also know well that there's zero support due from John on anything to do with this, given that the Pi branch is guaranteed to stay beta and I have no intention of using any of John's services that he provides to genuine Kiwis. It's as a curiosity for myself

From my own point of view, if this works as intended, I can do all of my WSPR listening and decoding on one device, with less noise and more self-contained. That would be a win.

I would happily paypal some monies to John if it does work as intended.
Cathal Ferris
RPi4 pulling from Kiwi-BBG with MLA-30 and a Kiwi-BBAI with indoor AAA-1c, in suburban Limerick Ireland
No callsign yet, just lots of in-depth SWL and receive tinkering..



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jks
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Re: New product from the Chinese, a Kiwi-thing + RPi

jks
In reply to this post by cathalferris
Not that it matters I suppose, but I'd like to clarify a few things. To be precise I don't object to the Kiwi "unlicensed clones" per se. I mean, it is open source after all. What I object to is the unlicensed use of my "brand". Specifically the name "KiwiSDR" and the Kiwi bird logo that I use myself under license from bluebison.net I don't want confusion in the marketplace such that people stop buying my stuff causing me to lose what little royalty I (and others) are getting from Seeed.

The latest device is at least calling itself "RaspberrySDR" (prior devices didn't), but still using the Kiwi bird logo. Although he's now holding, well, a raspberry I think. It's true that I don't have all the proper international trademarks to legally enforce my position. I'd be broke if I did and we'd also not have the 400+ software updates all my time has gone toward over the last six years. So it's more of a moral question. A quality that is curiously lacking in modern Chinese culture. Although fully understood if you're any sort of student of Chinese history (I personally have great respect for the Chinese from that perspective).

That 16-bit LTC2208 is a wonderful part. 10 dB better SFDR than the 14-bit LTC2248 used in the Kiwi (usual disclaimer applies about quoting ADC specs). But that part is also $80-90 (USD) through reputable, US-based distributors that provide traceable guarantees against counterfeiting and parts recycling (i.e. removed from old equipment in the Shenzhen electronic scrap yards). Recycling is not necessarily a bad thing. But my business model can't compete against it. The Kiwi ADC is $23 on a good day.

The end result of all this is that future Kiwi software features, that are not already bound by existing open source terms, will now be closed source. And distributed as "binary blobs" just as many of the closed source graphics card drivers are in your favorite Linux distro. Those features will be unavailable to the clones.

In addition the clones have been banned from participating in any of the kiwisdr.com value-added services such as the listing and map webpages and the reverse proxy service. Mostly because these services cost us real money to run. As with the free software updates they are an ongoing benefit of your original Kiwi purchase price.
Rob
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Re: New product from the Chinese, a Kiwi-thing + RPi

Rob
Hi John,
We all appreciate the tremendous amount of work you have been and are putting into the KiwiSDR and want to encourage you to continue your good work.
Our preliminary results suggests to me that the 16 bit ADC does very little to improve the WSPR  performance, so we hope we are on the path to proved there is no functional benefit to the KiwiPi.
Let us know how we can better support you!
Rob

 
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Re: New product from the Chinese, a Kiwi-thing + RPi

cathalferris
In reply to this post by jks
Hi John,
Thank you for responding.

I hope I make it clear that I want to continue supporting you if I can at all. How would I best identify the clone to you so that there's no issues from your side? Just ensuring that it is not attempting to register when it gets online? I know it relies upon my honesty on this, how do I ensure what I do is the right thing?

Where it may get slightly awkward is I hope to again put either a Pi or a properly-cooled BBAI under one of the KiwiSDRs I have, so I would appear to have more than one Pi-branch of code running at my QTH. If you do see a KiwiSDR with a Pi under it, it will not be the cloned one, it'll be the real one. I have no desire to put the cloned one online as it's exclusively for WSPR listening and decoding anyway, so wouldn't be using any of your provided services. Plus it would be unfair to have the expectation of support/services from yourself when using a clone. I also know that others would not be trying as hard to do the right thing.

Maybe in a new software revision, there might be the possibility of sending some information home as to whether the ASIC is your design or the clone (or something along those lines), and you can then blacklist that device. I suspect, though I really hope not, that there will be other oblivious buyers of the Pi device from the store that will plague the support network for assistance. I really hope that does not happen.

-Cathal (EI4IWB)

Cathal Ferris (EI4IWB)
Two standard KiwiSDRs listening to 14 bands of WSPR from an outdoor AAA-1d
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Re: New product from the Chinese, a Kiwi-thing + RPi

n6gn
In reply to this post by cathalferris
 Holger  Tom, WA2TP, and now Clint, KA7OEI have one of these operating using an image from someone in China.  As a result we've been able to make a few very preliminary measurements of noise, calibration, overload level, ADC linearity.

Without detailing the little that's been done so far, I think the current summary drift is something like this:

Calibration is approximately the same as the KiwiSDR at 15 MHz.  
It has the familiar gain shape v frequency, now doubled in frequency value.
It has significant aliased FM BCB response.
Noise floor appears very similar to the KiwiSDR, no better. Like the BBAI/KiwiSDR it seems to have lost the small characteristic noise bump just above midband, possibly attributable  noise from the BBG.
In the presence of a strong signal, noise floor lift seems to be considerably worse than the KiwiSDR (sample of one unit)

The extra two bits of ADC do not seem to be helping anything at all.  
It appears to hit top-of-ADC OV at about the same place so probably uses the same 1V reference.
The bottom two bits of the new ADC don't seem to be helping in any easily discernible way.
The main advantage to a user would be the frequency extension and whatever advantage the RPI environment has over a BBG or BBAI.
 In a typical use and location  it seems likely that it will need additional LPF filtering for protection from aliased signals.
The ADC runs much hotter and has its own heat sink.

I have 60 MHz wide noise plots which seem to reflect the (un)flatness of the gain shape mentioned above.
Glenn n6gn

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Re: New product from the Chinese, a Kiwi-thing + RPi

Powernumpty
Just in case it interests anyone my two WSPR Kiwi's are geniune capes but on Raspberry PI A bases (no Ethernet or USB Hub). The One called M0AQY is with an LZ1AQ oriented E-W and KiPi is same but N-S (and two joiners in the longer older CAT5 feed).
The N-S antenna seems less sensitive than the E-W but using the new merged reporting features I realised it was under voltage and perhaps even has dirty relays (things improved as replaced the supply and later kept changing modes). General noise levels here are variable so "quiet" is very rare.

I tend to think keeping the CPU and general heat in the build low helps reception (Johnson noise anyone). I know the Chinese clone is probably just built to make money but I think they missed a trick or two with what could have been done. They probably had a boss shouting "just bung some of these overstocked 5G bits on it and sell a bunch. (I too wondered about those expensive chips suddenly appearing in a number of SDR'S). I'd like to see an alternative path for the genuine capes where someone can take their existing cape and install it in another box with advantages of the ubiquitous PI's. I have played with the BeagleBone AI but they take too much cooling IMO (not to mention £130 here) the PI A is £23 and in my build passively cooled (or a slow fan across the outer case in summer).
Stu