HFU HF Underground
Technical Topics => SDR - Software Defined Radio => Topic started by: RobRich on September 11, 2024, 0309 UTC
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The Web-888 is more or less a LTC2208-based SDR standalone network receiver running a modified KiwiSDR-based software stack atop Alpine Linux using a Xilinx ZYNQ XC7Z010 CPU+FPGA. It supports 13 receiver channels with waterfall displays. Frequency ranges are 0-60MHz and 118-145MHz. HF+VHF antenna ports, hardware GPS module with port, Gigabit ethernet, active cooling, etc.
General details:
https://www.rx-888.com/web/
Design notes:
https://www.rx-888.com/web/design.html
Hardware:
Dimension (100mm*25.2mm*17mm) exclude SMA
Active Cooling Fan (40mm)
16-bit ADC DDC architecture SDR (LTC2208)
61.44 MHz real-time bandwidth
built-in all-constellation GPS module
dual antenna inputs
Gigabit Ethernet
reference clock input/output
24.576MHz, 0.5 ppm TCXO
8 expandable IOs for antenna switching
Software:
Alpine Linux 3.20 with Linux 6.6 Kernel
WebRX-based browser SDR experience
KiwiSDR websocket protocol for applications
WSPR, FT8 skimmers, and other decoders
13 RX channels and 13 spectrum channels simultaneously online
Binary updates with alpha and stable channels
Read-only root partition to prevent SD card corruption
FPGA DMA controller for efficient data transfer without CPU involvement
I have one on order from elekitsorparts.com:
https://elekitsorparts.com/product/web-888-16bit-sdr-receiver-64mhz-bandwidth-openwebrx-pre-installed-hf-vhf-gps-sdr/
It is also popping up on AliExpress.
Note you will need to supply your own power supply, network cable, active GPS antenna (if desired), and (AFAIK) TF/microSD card(s).
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Tech Minds has a video review of the Web-888. It is not a deep dive into hardware performance, but it does offer an overview of the software side. KiwiSDR users should feel at home.
https://www.youtube.com/watch?v=3FpntwHhY9o
Mine has shipped, so hopefully I will receive it in a week or two. I do intend to put it online.
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Will be interested in seeing one online and how it compares to the Kiwi performance wise. As well as seeing how it compares to the previous 16 bit 62MHz takes on the Kiwi (RaspberrySDR and FlyDog).
At ~$260, the price sure isn't bad, but the one thing that concerns me about these is future support of the unit. They are running modified versions of the Kiwi software and doesn't receive the same updates as the Kiwi. So, you're going to rely on whoever developed the clone to make sure it gets updates that align with browser changes, OS changes, discovered security vulnerabilities...etc. I believe folks already have problems with getting updates for one of the previous Kiwi clones.
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I had been considering a RX-888 Mk II, but the Web-888 launched in the meantime. It was not a huge markup for the added SBC and software stack, so ended up going with the network model.
About the design, it is basically a RX-888 on the receive side but more like a Red Pitaya on the SBC side. The UI is certainly largely derived from Kiwi and OpenWebRX, though.
Howard Su is one of the devs. He seems more committed to the project than some of the previous KiwiSDR clone efforts perhaps hoping more or less simply to cash in on a lack of official Kiwi hardware at the time.
Notably there is an actual public repo with dev activity. :)
https://github.com/RaspSDR/server
At least that gives the community a foundation for further development and support even if the official project is discontinued down the road.
If development outright stops and security eventually becomes an issue, owners can drop public access and repurpose the units for whatever local roles. Not sure I need 13 more SDR channels for my own listening purposes, but I would still get the benefit of real-time 0-60MHz spectrum.
The Web-888 arrived yesterday. I will try to get my Kiwi and it online maybe today or tomorrow. I need to reroute some feedlines.
Also I wanted to change out my currently basic wire LoG with my previous coaxial "shielded" LoG design for feeding my network SDRs, though that plan is likely delayed pending possible tropical weather here this week.
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Initial preview demonstration of the WEB-888 software defined radio. The firmware is the current version 2024.0901 stable release. Antenna is an 148' loop-on-ground in conjunction with an inexpensive preamp and active splitter.
https://www.youtube.com/watch?v=F7x-yB0wgOs
I still need to work on the software configuration, add various ferrites, plus perhaps swap around antennas and/or preamps. I will try to get it public in the next day or few.
(https://i.ibb.co/8B6S34x/Screenshot-20240926-141040.png)
(click to enlarge) (https://ibb.co/hMDt51d)
I have not configured location data for the Web-888, and it is not connected to GPS right now. Stats have been back and forth between the two. One might snag a station the other does not and vice versa.
(https://i.ibb.co/gFD0tvT/Screenshot-20240926-141634.png)
(click to enlarge) (https://ibb.co/Z1hQcH8)
Of note regardling zoom levels for the Web-888:
This switch controls how many spectrum clients we can support. In Shared mode, there are 13 clients with WF supported, and each client can only zoom up to zoom level 9. In Exclusive mode, only two clients can use spectrum but it can zoom up to zoom level 13.
Source: https://www.rx-888.com/web/guide/admin/control.html#share-or-exclusive
Max zoom for mine appears to be seven for shared mode, though note I am running the older stable firmware release right now, so there could be changes in later test build revisions.
Sure enough regarding zoom levels and firmware.
Feature: Maximum Zoom Level in Shared Mode increased from 7 to 9.
Source: https://www.rx-888.com/web/downloads.html#changelogs
Updated to alpha release. Max zoom level is nine in shared mode now. :)
Public Web-888 SDR listings:
https://www.rx-888.com/web/rx.html
There are four listings at the moment. Mine should add shortly, though it might be up and down for awhile pending various changes.
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Stay safe, sounds like that storm is going to be a doozy.
Looking at those already online, they look decent.
Does it have other configuration modes like the Kiwi does for a wider bandwidth such as ±10.125kHz at the expense of a reduced number of available channels? Also, I often use zoom level 14 on the Kiwi as I like to see the carrier(s) and their offset(s), especially when DXing AM, so that would be something I'd like to see with these too, even if it reduces the number of available channels.
Overall they look and feel very much like the Kiwi.
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My KiwiSDR v2 with 148' loop-on-ground:
http://21084.proxy.kiwisdr.com:8073
My Web-888 SDR with 31' vertical:
http://web888.servehttp.com:8074
I had them both on the 148' LoG, but I prefer having access to different antennas for my own personal use.
Both are on an AC line conditioner but not an UPS at this time, so YMMV on them staying up tonight considering the tropical weather here.
Also I likely need to tweak the WiFi router bridging my SDRs to my WiFi network, such as perhaps enabling SQM with some rather constrained limits since the SDRs are not really bandwidth intensive devices.
Waterfall access can be configured for exclusive mode. That increases max waterfall zoom levels, but it also limits the full waterfall to just two channels.
The only FPGA mode (for now?) is 13 channels with 12KHz max audio per channel.
Thanks for the positive thoughts, nitroengine. :)
Bands are moving through my coastal county right now. Been listening to the wind, but I still have power (for now?). I am inland somewhat, so at least my neighborhood is spared the storm surge. The immediate coast and islands could very well be underwater. I am hoping people out there evacuated.
Enabled SQM on the bridge router for both WiFi download and upload. Tried streaming channels from both SDRs while running speedtestcppp on the router to load up the network bridge. Seems okay for now.
I *thought' my Web-888 was on my 31' vertical, but it has been on my 30' inverted delta loop. o.0 I noticed a lack of attenuator after my preamp, and that would typically overload many receivers at night using my 31' vertical.
Swapped to the 31' vertical, tweaked attenuation, and the end result is the Web-888 is still favoring the 30' inverted delta for SNR ratings. Anyway.
For awhile I had an active splitter feeding my 148' LoG to my Kiwi and Web-888, but it affected SNR, so that is not going to work. I get the feeling I will be deploying another LoG for the Web-888 at some point.
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Received my WEB 888 last week. Been running 11 simultaneous instances of WSPR reporting, 160m through 10m plus a random channel for SWBC listening. DRM and SSTV work well with no tweaking required. Amazing.
Paul, W9AC
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Hello from Germany (Dresden),
I also received my Web-888 from AliExpress a few days ago and I think the little device is great.
It generally runs with the current Alpha software without any problems.
Only my antenna situation is a bit suboptimal in the attic. It is currently running with a YouLoop.
http://web888.jimjackii.de
Regards, Steffen
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Hi Steffen! Welcome to the HFU community. :)
I am running alpha releases as well. I have even compiled a test binary with link-time optimization for perhaps a slight performance boost. It builds, but I have not yet tried deploying the binary on my Web-888 for testing.
There is still development work to sort out with some of the more advanced features, but most standard features work okay in my experience.
Assuming local RFI noise is not too overwhelming, you might consider adding a preamp with your attic YouLoop if not already done. The YouLoop is well into negative gain on HF and lower, plus its impedance curve variances from 0-30MHz are rather extreme.
My Web-888 is still on the outdoor freestanding 30' inverted delta loop. Near the Web-888 I have a cheap TQP3M9037 RF preamp with a 10dB attenuator on the output for now. Daytime SNR is not great here, but the setup suffices for casual listening, while nighttime SNR is usually decent even compared to my KiwiSDR 2 with 148' loop-on-ground and preamp.
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Hi Paul! Welcome to the HFU community, too. :)
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Take a look at the WellGood loop. Based on the legendary Wellbrook ALA1530.
https://www.george-smart.co.uk/projects/wellgood-loop/
As mentioned, if using a YouLoop, you'll probably want to pair it with an amp.
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Hello RobRich,
thanks for the welcome.
I have a preamp on my YouLoop and the SNR isn't particularly good, but it's more than adequate for occasional listening. So far I'm satisfied with the Web-888, it runs stably for me.
I also have an OpenWebRX+ installation on an Intel NUC with an AirSpy HF+ Discovery on the same YouLoop with amplifier. Both have roughly the same reception.
Regards, Steffen
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Getting back into the hobby and have a web-888 publicly available. Took a while to get some hardware and noise issues ironed out but it's finally online. Still have some minor noise but I'll be working on that.
http://blerp.proxy.rx-888.com:8073/
the_axis
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Waterfall max zoom has been increased in build 2024.1228. I have deployed the build, along with own LTO optimized websdr.bin binarry, on my public Web-888.
Increase max zoom to 14 on exclusive mode and 11 on shared mode. For exclusive mode support, please update full image which contains Linux Kernel update.
Source: https://www.rx-888.com/web/downloads.html
Updated. The 2024.1228 build is working as intended.
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I think I'm going to pull the trigger on buying one of these from AliExpress, along with the GPS antenna. My Ham-it-up upcoverter is way too sensitive to temperature fluctuations and causes too much drift. I'll just use the NESDR SMART for VHF/UHF, which seems fine, and maybe sell the upcoverter on ebay or something. Perhaps the upcoverter would function better in a box, but I can't imagine it would make it that much more stable. You can literally hear the drift when tuned to WWV when the heater kicks on. Not good! I'll let you all know when I get the new SDR and I'll put it online.
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I did order the WEB-888 from AliExpress. Says it shipped out on the 18th. It was cheaper than on eBay.... and all coming from China either way, as none of these units ship from the USA.
In preparation for this I bought an SD card and an active GPS antenna.
EDIT: Came in TODAY! I wasn't expecting this till Feb, but it arrived in 5 days. I wasn't ready for it as I haven't got all my parts in to assemble the new antenna I'm going to build for it. My ears don't hear well below 3-5 MHz as I'm using a TV 4:1 balun for my temporary dipole. I'll day this.. it's ACURATE!
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So, I've tried a mobius loop antenna, which was way too quiet without a preamp. I settled on an inverted L, though I'm not sure a 9:1 unun is correct, given it's not a pure end fed antenna. I'm not sure you can make an L a broadband antenna. It is disturbing how much noise is present in the lower bands, like from 160-40m. But when it's clear, it's CLEAR. I'm going to keep refining this as per numerous articles on this topic. I have HORRIBLE noise below 500kHz, which I suspect is from the dirty power supply and from the HVAC motors from my house and the neighbors'.
Aa far as the VHF tuning, I built a 1/4 wave groundplane centered on the phone portion of the aviation band, and it performed perfectly!
I'm VERY impressed with this SDR. I don't like how it's missing some features that the Kiwi has. I'll leave that for another topic. But, so far, I'm pretty happy with this purchase.
Listen in sometime at http://75.134.33.242:8073/ . No guarantees that this IP address will always be valid, but feel free to give me some feedback on the reception. Currently, I have it set up to do 0 to 30 MHz.
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An inverted-L can be "broadband" in the sense a moderate-sized version can cover much of the HF spectrum. It is likely to also suffice at low frequencies since atmospheric noise swaps even relatively small antennas down there.
I would have to perhaps research it further, but IIRC, even an inverted-L at like 22' vertical by 22' horizontal or so actually shows decent lobes across a considerable swath of HF spectrum. Efficiency drops considerably at lower frequencies, but most receivers have plenty enough gain to offset the differences.
The 9:1 unun should suffice. Oftentimes it is often more about improving common-mode isolation than improved impedance matching for HF receiving antennas; withing reason of course. Considering it is an unun, you might want to experiment with an 1:1 galvanic isolation choke behind it if not already present. Also if just using a ground rod or similar, opting for a few on-ground radials might further improve efficiency.
VLF noise is a common issue even with a clean power supply and good galvanic isolation of the antenna. Unless you are perhaps in the middle of nowhere on a large rural plot, expect plenty of low-frequency noise these days.
That said I am in a neighborhood and often note plenty of NDBs plus even an occasional longwave broadcast, but reception of those tends to fair *much* better with my Airspy HF+D and 31' vertical. The HF+D has rather impressive dynamic range, selectivity, image rejection, etc. for a sub-$200 receiver.
Pending controversy over US government shortwave broadcasts aside, on a technical note, I can probably up amplification on my 148' LoG if Radio Marti discontinues on 6030. Right now it is my worst offender for overload here even with my 148' LoG well into negative gain numbers. o.0
My online SDRs are slightly down on the SNR charts for now. Awhile back I replaced my cheap preamp with the following:
https://www.sv1afn.com/en/product-category-5/high-linearity-pre-amp-(lna)-for-hf-receivers-30-khz-30-mhz.html
It is much cleaner overall, especially from an electrical noise standpoint, but it can sometimes overload a little when Radio Marti 6030 is on the air, even with currently (IIRC) 10dB attention on the input side. That attenuation tends to drop my SNR measurements by a few dB. Anyway.
Next I need to toss the current inexpensive active RF splitter for hopefully a little further signal cleanup. It appears somewhat electrically noisy at lower-HF and below. A passive splitter on a mix 73 binoc core for feeding my online SDRs should likely suffice for my purposes.
Speaking of preamps, I have a couple of inexpensive W7IUV-style preamps from AliExpress needing further evaluation. Not exactly a high-end preamp design compared to more modern designs, but the rather simple circuit is still quite popular. Naturally they have the usual cheap counterfeit 2N5109 transistors considering the low price point, but I have a few vintage (IIRC) RCA 2N5109 transistors available for swapping.
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How is the weak signal reception performance on WEB-888 SDR? You seem to be saying that on the LF band, the other SDR performs better. Would be correct?