SDR transceiver for digital and other stuff - Page 1
Forum section: electronics / rf-microwave

author: pipe2null
author_rank: Regular Contributor
timestamp: December 17, 2019, 05:10:38 am
content: Hello all!I'm a total newb on the RF side of things, but I am taking the plunge. Fortunately, I have a few specific projects in mind, so I have a rough idea on what functionality I need although I'm more than a bit shakey on specific specs. I've been digging around attempting to narrow down on a specific purchase. It goes without saying that I am already buying an RTL-SDR blog v3. When I'm done playing with it, it's going on the window sill as a dedicated FM tuner for local stations to stream on my local network.But I'm pretty sure I need an SDR transceiver for upcoming projects. Generally speaking, I need to dev, test, debug, and monitor various wirelessly connected devices, nothing terribly fancy toSTARTwith, just arduino's. Some projects will have devices with different roles/FW talking to each other and I want to dev/test/debug them individually via desktop. Other projects will be more of a base station/slave device type arrangement, my desktop intended as the base station and general dev machine. Most of my grab-bag-o-parts for RF communication all use 2.4GHz, but there are other devices I want to hack on that use 400ishMHz, and who knows what else I might find that I want to mess with. The website fcc.io is so informative... Heh. I am not specifically interested in lower frequency stuff or listening to HAM stations (or getting my licenseat the moment), but since I haven't messed with it before, I have no idea what I might get into down the road and I do not want to limit myself.Before you tell me to just go mess with the RTL-SDRfirst(whichISgood advice): I have family members who keep bugging me wanting to know what I want for the holidays. While I strongly doubt anyone is going to buy me a mid-range SDR as a present, it sure would be nice to find a pack of antennas under the Christmas tree that just-so-happens to work (correct connectors out of the box, etc) with the SDR that I'm getting anyway...So, I'm trying to finalize my SDR transceiver decision within the next week as result.Other basic info: I am on Linux and am familiar with the pros/cons of open source. I still have Windows sitting dormant on another partition, and I want it to stay dormant, but if there is no other way to do something......... Well, I kept Windows around for worst case scenarios. Also, I have zero FPGA experience, but I'm open to learning down the road a bit.General SDR transceiver Use Questions:Are there any issues I should be aware of using GNU Radio for digital Rx/Tx, or would I have to use one of the APIs? (yes, I'm total newb on subject...)Can an SDR with multiple Rx/Tx (MIMO) be used independently? Specifically, I would like to have one (ideally duplex) Rx/Tx set continuously running as a base station (arbitrary homemade protocols) while I use the other set for dev/test/debug on a different frequency. Same question: can Rx channel be used independently/different frequency of the Tx channel?If you have any feedback on the following, please share. Narrowing down my transceiver purchase decision:I have looked athttps://en.wikipedia.org/wiki/List_of_software-defined_radiosBudget wise for an SDR transceiver, I really need to keep it under $500 including a starter set of antennas. If it turns out to be really important, I can be a tiny bit flexible on budget, but not by much. This is especially true since I am seriously looking at buying a spectrum analyzer for my home lab... I'm not 100% committed to the SA purchase yet, but I'm pretty close. That said, if my laptop had a mini pcie slot available, I do not believe I could resist picking up a Fairwaves XTRX (https://www.crowdsupply.com/fairwaves/xtrx) simply because it would be freakin cool to have something like that installed internally on my laptop... Perhaps some day, but not today...I really do not want to buy a second transceiver if I can avoid it, at least not for a long while. If I can use sets of Rx/Tx channels simultaneously/independently as base station plus general purpose RnD on different frequencies, then I would much prefer an SDR with that capability. If I absolutely HAVE to get 2 separate SDRs, then my per unit budget gets cut in half and so does the HW capability.I alternate development between my desktop and laptop, so at least my initial/primary SDR needs to be USB connected.The SDR must cover at least the lower MHz range through 2.4GHz band, and just about all of them do. I wouldLIKEit to cover 5GHz plus low frequency too, mainly so I am not limiting myself, but that is a lower priority. The more bandwidth the better: doing sweeps is not really a primary use for me, but it's something that I'll be doing on occasion.At some point down the line, I probably should try and get some FPGA coding experience, and an SDR with the capability and space for user loadable "code" would provide a good practical opportunity to do so, but that is a further off and much lower priority goal.HackRF:I scratched HackRF off my list since I hesitate due to no subsequent hardware revision in all the years it has been around, plus there appears to be better spec hardware for similar or lower prices. Don't get me wrong, I think the HackRF is awesome for a list of reasons, but I don't think it really fits my needs.LimeSDR:This unit keeps popping up, and I keep going back to their website. But I have heard something about overheating issues (https://www.eevblog.com/forum/rf-microwave/limesdr-versus-hackrf-one/msg1395442/#msg1395442), and I've not found much chatter on Eevblog about it in recent months. Has anyone been using one of these lately that could provide some input?BladeRF:Please correct me if I am wrong, but this SDR seems more appropriate for FPGA related SDR work, which I am not ready for/capable of yet. Plus, it is getting a bit beyond my price range. If there are really good reasons to go with bladeRF over something like the Lime, I might consider it though.If the MIMO SDR channels will not work independently like I asked about above, then it sounds like I have to get separate SDRs, so the cheaper models:PlutoSDR/ADALM-PLUTO vs LimeSDR-mini:A hacked Pluto can do up to 6GHz, but the USB3.0, BW, and ADC of the mini Lime ...I keep going back to the LimeSDR, but I have no idea if it is a good choice for my intended purposes (andtemporarytotal RF newb status) or if there are other SDRs I should look at before making a decision?Any feedback would be much appreciated!

author: OwO
author_rank: Super Contributor
timestamp: December 17, 2019, 05:55:43 am
content: LimeSDR is good as a usb-to-RF dongle, but not much more. The FPGA on it is seriously underpowered and has no access to any significant amount of memory, so this precludes doing any but the most trivial DSP. PlutoSDR is good for FPGA DSP experimentation (it has a Zynq that has access to DRAM with 1GB/s of usable throughput), but the USB interfacing is not well implemented and it's a pain to use as a USB-to-RF dongle. XTRX is a nice idea on paper but has a fatal design flaw - there is no on-board DDR memory and PCI-e access is far slower. "PCIe x2 Gen 2.0: 8 Gbit/s"? That's a fraction of the memory bandwidth I can get on a puny Zynq (with both DDR channels populated as opposed to just one on the Pluto), and I can easily max out the DDR bandwidth just doing FFTs, and even then it still isn't fast enough to transform the 60Msps input in realtime without gaps.The Pluto does have a few serious limitations (very little flash memory and no SD slot so can not run real Linux distros; only half the memory bandwidth because only half the DDR channels are populated; 512MB also really isn't enough when you have lots of dedicated DMA buffer regions AND also want to run web servers serving 100 users), so I designed my own:https://github.com/gabriel-tenma-white/sdr5(note: design not yet fully verified, don't build from this without looking it over)It really depends what you ultimately want to do with your SDR: do you just want to use it as a *software* defined radio where all processing is done on a PC? Or do you want to play with FPGA DSP as well? If it's the former, go for the Lime, and for the latter, go for the Pluto, or build your own using the AD9363.

author: pipe2null
author_rank: Regular Contributor
timestamp: December 17, 2019, 07:24:02 am
content: Hmmm... Well, my intention is to use the SDR as a general purpose debugging tool for wireless devices, with a side purpose of being a base station for a subset of those devices, plus whatever other "practical-to-myself" use I can get out of it. Learning FPGA is certainly "practical-to-myself" but I need the SDR as a debug tool and base station long before I can get into the FPGA side of things. Up to the moment I've been avoiding making the SDR itself another project (to add to a VERY long list of projects that keep piling up...).I haveassumedperhaps incorrectly that the SDR would have to be connected to a PC all the time and I have not really considered the possibility as a standalone device. Without having any experience in this area yet, I have no idea how to determine for each model where the line is drawn between on-device processing and what is simply dumped to the PC for PC software solely to deal with. Quite obviously, the more on-device, the better. But I need an SDR that does not require me to learn FPGA prior to using it as the debug tool I need initially.Way down the road, it would be a really great project for me to push my base station code to the SDR's FPGA (if that is the correct way of looking at it?), so it would be really nice if whatever equipment I invest $$$ in has enough capability/head room for that future project, and more if possible. But I need to develop a clue what the heck I'm doing long before then...So it sounds like LimeSDR will fit my current needs well, but lacks any real head-room for down the road projects, and the Pluto might be useful to me down the road, but doesn't really fulfill my current needs...Are there any other SDRs I should take a look at that are above entry level in capability, preferably MIMO if the channels can be used independently, but does not require professional-grade technical expertise to get started using it?

author: vk4ffab
author_rank: Frequent Contributor
timestamp: December 17, 2019, 08:15:07 am
content: There is a third option GNU Radio and do it all in software on a pc and just use simple low cost hardware.

author: m3vuv
author_rank: Super Contributor
timestamp: December 17, 2019, 09:17:12 am
content: nothing mentioned about getting a ham licence for tx i see,i think that should be top on the list before the hardware!!

author: 9aplus
author_rank: Regular Contributor
timestamp: December 17, 2019, 09:40:37 am
content: @pipe2nullHere can share some of my experience... I am an old HAM licensed since 1974. was 10 y/oldStarted with SDR-s about 5-6 years ago... Before that have some info about TV USB stick-s but considered them not serious enoughMy first SDR was SDRPlay RSP 1, still own and use 2 unitsThan purchased for reference RTL-SDR v2, still own and use from time to timeThan participated in first LimeSDR USB campaign, today use and own 2 units, no cooling problem if properly handledAnd last one was LimeNET micro campaign, was not happy with delivered configuration - no duplex hardware on campaign board,still trying to find good use of this one. Tested in USB 2 mode, working good enough on RX even on 7 MHz with some LNA4HF assistance,on TX hope Simon can resolve issues with SDR Console, now TX is working from 28 MHz and up. Now preparing some PiSDR configurationto remote run of this one using old ICOM PCR1000 like front end, taking signal from 10,7 IF.Please keep in mind that Lime needs proper band filtering in front, and low pass filtering on TX.SDRPlay can be used good AsIsRTL-SDR have limitations but for that price level it is excellent hardware.All around SDR is learning curve in HW and SW, if you can accept that, you can go and explore...73

author: pipe2null
author_rank: Regular Contributor
timestamp: December 17, 2019, 10:11:07 am
content: @9aplus: Thanks for the info. I'm definitely going to spend some time on the listening end of HAM. I was actually looking at an SDRplay Duo for a bit before I headed toward a transceiver instead for learning/developing with digital wireless. FYI the Duo is on a holiday sale for about $220US until 12/25.@m3vuv: I mentioned license in OP. Tx is only for debug of wireless devices located literally a few feet away, so whatever the lowest setting the SDR exposes, that is what it will be. When I refer to "base station", it is still only communicating over roughly 15 feet max radially, so, again, the absolute minimum Tx power. If my needs and/or interests change, getting a license for more general use is something I've considered, but it doesn't make any senseat the moment. I probably should have made "at the moment" bold in my OP. Sorry, I should have been more clear about that.@vk4ffab: True, on GNU Radio. And to start with, I'll have to do it all in software mainly because I'm new to RF and have no experience with FPGA. By the time you get antennas and the cheapest transceiver, its already costing a couple hundred. Going with something like the Lime will be a couple hundred more but I at least have the impression that the hardware characteristics as a USB-to-RF dongle are worth it. But now the price tag is getting around $500, which is ok, but if I'm spending that much, I need to make sure I have some head room not just for current projects, but some down the line projects as well. Plus, I'm also looking at picking up spectrum analyzer as part of my overall setup, so more reason I need to make sure this purchase is not just a short term solution. The worst thing for me would be if I spend $500, use it for 6 months, only to find out I should have purchased a different SDR, or spent a little bit more up front to make sure I had at least a little room to grow, so to speak. I can afford one purchase, I cannot afford to have $500 collect dust on the shelf while dropping another $500-ish or more to buy what new-found experience will tell me I should have bought in the first place. Heh, that is my personal Murphy's Law, and I've long since grown tired of kicking myself after I realize I just spent twice as much attempting to save money than I would have spent if I had just purchased the right tool for the job in the first place. Case in point: Buy a miter saw BEFORE you start building shelves, workbenches, and other projects that have lots of angled cuts... Heh.The more I consider OwO's reply, the more I think I really should make sure my SDR has MIMO and the FPGA side of things has some room to grow... Heh, great... Now I've thought of 3 more projects to add to the list...Thanks alot OwO!Anyone know of an SDR transceiver that is roughly on par with LimeSDR but has a better FPGA/DDR story (see OwO's comments for what I'm referring to), but not quite into the professional price range?

author: m3vuv
author_rank: Super Contributor
timestamp: December 17, 2019, 10:30:32 am
content: any tx on bands other than licence free requires a licence no matter what the power!!

author: vk4ffab
author_rank: Frequent Contributor
timestamp: December 17, 2019, 10:33:41 am
content: Quote from: m3vuv on December 17, 2019, 09:17:12 amIts not needed for what he is doing. It will be covered by the LIPD or Scientific class licences in his country.Quote from: pipe2null on December 17, 2019, 10:11:07 amPersonally, if it was me, i would get a hackrf one, to use as a transmitter and an rtl dongle as the receiver. Actually this is what i did lol then built filters and amps to suit for 2m and 70cm ham use amoung other things. Then added a better sdr receiver and home brewed some cw transmitters.

author: 9aplus
author_rank: Regular Contributor
timestamp: December 17, 2019, 10:37:12 am
content: For TX, he can also use close circuit with att and dummy loads....Regarding Spectrum A for starter you can use SW working with all SDRPlay units,but soon you need some signal generator too. Here use some moRFeus and EraSynth+

author: OwO
author_rank: Super Contributor
timestamp: December 17, 2019, 11:44:24 am
content: I'd personally probably just get a Lime mini ($160) if I was starting out, and by the time you actually need to do serious DSP on a FPGA you'll probably be on custom hardware anyway. $500 is a lot of money and I think I spent a lot less than that developing my sdr5 (the one linked above) even with 2 iterations to get it working.On a PC and at large bandwidths (> 1MHz) MIMO isn't very useful because you won't be able to do much with the data other than a simple weighted sum (beamforming). Better use a directional antenna instead.Also I wouldn't spend much money on antennas; it's much more fun to design and build them yourself. Lots of ex🅱️ensive antennas out there are simply woo and perform nowhere near spec. Long time ago I built a yagi-uda antenna by folding copper foil into triangular rods and then soldering them together. For UHF there are lots of biquad antenna designs on the internet which perform as stated. You can build these with nothing more than blank PCB, some coax, wire, and a SMA connector. For HF/VHF I recommend building magnetic loop antennas.

author: pipe2null
author_rank: Regular Contributor
timestamp: December 18, 2019, 01:03:56 am
content: Thanks! You've given me quite a bit more to check out and consider. All of your feedback is much appreciated!My current and future SDR needs require a transceiver, at the absolute minimum Tx power (1m-5m radial distance max) and only at license free frequencies, but I'm not going to spend money on a "crippled" or under-performing device for my lab. If my needs change down the road, the first step will be to get my license,no argument there. A basic set of antennas should suffice, although I like the idea of simulating and building my own and I'll be building an "EEVblog #1178 - Build a $10 DIY EMC Probe" at the very least. I am getting an RTL-SDR for "my apartment", but the purpose and use of that purchase is completely mutually exclusive of "my lab".At the end of the day, I'm expanding the capability of my home lab to include RF (license free,for now) Rx/Tx forgeneral purposeRnD of digital devices and simplistic homebrew wireless digital protocols. To date, I have not spent a single penny on anything application or protocol specific, nor anything that doesn't fit the "general purpose" criteria. Even the components used in the devices I've built so far have come out of my "general purpose" part supply. In a word, "Legos".While building up my lab as economically as I can while still enabling the maximum capability, I've cut corners on equipment that is easily replaceable cost-wise like buying a cheap soldering rework station and using an adapted PC power supply on top of my bench. But I went with a new (hacked) 350MHz oscilloscope since it is both dependable and will cover all current and future needs, at least until I need something on par with high speed USB. I'm very likely to pick up a spectrum analyzer for the same reasons, a (hacked) SA will cover all current and future needs, at least until I need something in the 5GHz range.I need to do the same with an SDR transceiver. Since the minimum cost of a transceiver with a basic set of antennas is hundreds of dollars, I cannot consider it "easily replaceable", so the equipment I buy needs to cover all my current needs, plus a substantial portion of all future needs, at least until my needs grow to the point something well into the $1500+ professional range is required (at which point I should have enough acquired knowledge to build my own, as OwO pointed out.)I freely admit my ignorance on the subject, and I'm working to correct that. But to really learn this stuff, I need to upgrade my lab with an SDR transceiver that will cover my current and much of my future needs. I have the impression the LimeSDR covers my current needs pretty well, but doesn't have a good FPGA story to fulfill future needs (I should probably learn FPGA before designing my own board that uses FPGAs.).This is where I'm stuck making a final purchase decision:An SDR transceiver on par with LimeSDR but with more "room to grow" appears to be what I should be targeting AFA my general purpose lab is concerned. BUT I do not have sufficient knowledge (yet) to identify which SDR model fits the bill.

author: bson
author_rank: Unknown
timestamp: January 01, 2020, 06:54:38 pm
content: What's the certification on those SDR transmitters? It would seem like FCC Part 15 compliance is a hard requirement for any unlicensed operator. I have a strong gut feel they're ALL Part 97 "kits", meaning he will have to go get an amateur radio license to transmit. If they were restricted to Part 15 they'd be too limited to be marketable to licensed users, and in a cursory glance at product pages I found no mention of type licensing or regulatory compliance of the ones I looked at. Meaning we're talking Part 97.

author: on7yi
author_rank: Contributor
timestamp: January 08, 2020, 12:35:16 pm
content: I don't know why nobody mentions the redpitaya in this post. I actually own three of them as well as a plutosdr.What is nice with the redpitaya is that it comes with 14 or 16 bits sampling depending on the model which is much better than the usual 12 bit sampling offered by the LIMESDR and the PLUTOSDR. The fact that the hardware is commercially available hardware and distributed everywhere is also quite nice. Last but not least the software of Pavel Demin is really exceptional in terms of quality. That software is HPSDR compliant which means that the GPIO pins of the redpitaya can be used to directly control a number of external devices such as filters, pre-amp, attenuators etc... I paid 200 euros only for the last 14 bit device that I bought NEW on eBay. If you blow your redpitaya you can easily buy a new board to replace it, or if like I did when I blew up the Zynq 7010, you can easily repair it based on the development schematics that are published by STEMLAB. It is not really open hardware like the Pluto is but it is not closed hardware either, all in all enough information is available so you can modify, repair and even upgrade your board yourself. I personally upgraded a board from 14 to 16 bit, changed its clocking frequency from 125 Mhz to 122.88 Mhz, upgraded the FGPÄ from a Zynq7010 to a Zynq7020 using cheap components available on AlieExpress as well as modified the rf-frontend and rf-backend to optimise rf-performance. All this without too many issues, no need for re-flashing via JTAG ports as the software is stored on an, SD Card. Lots of documentation is available on the web and many people implemented some of the mods to optimise the performance of the redpitaya board as an SDR transceiver, so it is a well proven track for building a home made transceiver based on SDR technology. My redpitaya work beautifully well with PowerSDR and QUISK for SSB but for digital communications I prefer the SparkSDR/WSJTX combo. I tested linhpsdr but the development is not finished yet so I won't comment.What is not so nice is that the redpitaya board must be optimised to sqeeze the best performance out of it, so it is definitively not a turn key solution like the HiQSDR, Odysey 2 or Hermes Light II boards are. I won't get into details here, but the output power is limited to 5-10 dbm max depending on the model. On the 14 bit model the inputs are high impedances so some rf transformers are needed to lower it, on the 16 bit models the inputs are natively low impendence but an external anti-alias filter and an excellent shielding of the board are mandatory to work in HF. For VHF/UHF, band-pass filters are mandatory for working in the band of interest with the 16 bit model or the modified 14 bit one. Pending the usual limitations of under-sampling, the 16 bit redpitaya model or the modified 14 bit one receives quite well up to 2.4 Ghz but the redpitaya can not realistically be used to transmit SSB signals above 500 Mhz as the spurs produced and unwanted aliases produced are just too hard to filter even with a saw/baw filter; in transmit mode some classical upconverter technology is mandatory above 500 Mhz. Even below 500 Mhz, there are the usual "frequency gaps" linked to under-sampling technology where the RP can not transmit/receive at all. One of these 3Mhz gaps falls in the upper part of the 70cm band for modified 14 bit model clocked at 125 Mhz, but with the 16 bit model clocked at 122.88 Mhz it is not an issue.The AD9361 chip of the plutosdr is nice, but its rf performance is quite limited in terms of (a) third order intermodulation - see videos on YouTube about that - and (b) in terms of isolation of the local oscillator when the pluto is used in full duplex mode and when operating on nearby TX/RX frequencies (so transmit and receive at the same time on nearby TX and RX frequencies), in this scenario there are unwanted and undesirable spurs in the receiver that depending on the use-case can be bothersome (or not) to receive weak signals; it looks like the TX local oscillator leaks into the receiver, so when TX frequency is too close from the RX frequency, it may be an issue. I am not convinced the PlutoSDR is the best hardware base for building a home made SDR transceiver but it certainly works very well if one accepts those two drawbacks. I remain quite satisfied considering that I bought my PlutoSDR for 90 USD!!!! and considering that this boards covers the frequency range between 70 Mhz to 6Ghz !!!!. My PlutoSDR hardware works quite well with SdrAngel and SDR Console 3 software, however neither software is HPSDR compliant which in practical terms means that you will need to think of a custom solution to switch your filters, route your rf signals based on your specific use -case. Output power is in the oder of 0 to -10 dbm depending on the frequency.Regarding the use of the redpitaya and plutosdr with GNURADIO, both the redpitaya 14 bit model and the PlutoSDR can be easily interfaced (source and sinks available) with it. Unfortunately, unless I am mistaken (which is always possible), to date, there is not yet any software to easily use the latest 16 bit redpitaya model clocked at 122.88 Mhz with GNURADIO.Same story regarding SoapySDR, if your favourite SDR program (ie GqRX or alike) supports the SoapySDR interface, you should have no problem using the 14 bit redpitaya model or the PlutoSDR with it . There are notable exceptions though; So far QUISK and linhpsdr support only SoapySDR in reception mode, so it is not possible to support the PlutoSDR in transmission mode with QUISK and linhpsdr. Again, the software available for the 16 bit version of the redpitaya clocked at 122.88 Mhz does not at the moment of writing these line support SoapySDR. It is worth mentioning that SdRAngel is the only LINUX based application that supports both the plutosdr (in native mode) as well as the 14 bit redpitaya model (via the SoapySDR interface).Having played with the RTLSDR (8 bit) in the so called "direct conversion mode", I would really not recommend using the HackRF for building a quality SDR ham radio transceiver in HF, the dynamic range is just not sufficient in reception mode given the huge dynamic range in HF as well as given the interfences caused by unwanted down-conversion of VHF/UHF signals in HF bands above 17 Mhz. However, why not in VHF / UHF, 8 bit could work, but then the plutosdr (12 bits) is a much better choice for many reasons. If money is an issue, in HF better use a good old Audio 24 bit sound card a la "SoftRock" and QUISK supports the SoftRock interface and audio soundcards.

author: OwO
author_rank: Super Contributor
timestamp: January 08, 2020, 01:54:06 pm
content: Yes, the AD9363/AD9361 is pretty bad linearity wise, and you *will* need preselector filters for your band, otherwise my experience is the FM broadcasts modulate with each other filling up the spectrum, and wifi signals are seen regardless of what frequency you tune to. Unfortunately it's the best you can get when building your own SDR, because the LMS7002 (used in the Lime) is unobtainium (at a reasonable price at least). If I was designing a product I'd design in the AD9363, then once there is enough volume negotiate with Lime and say "give us the LMS7002 at X price and we will switch".

author: on7yi
author_rank: Contributor
timestamp: January 08, 2020, 02:31:26 pm
content: It's really incredibly bad indeed. I attempted to shield my pluto in an aluminium enclosure making wholes only for a type USB female type A OTG connector, two 5mm leds, a 5mm flip-flop switch, the two sma connectors and some GPIO connector (5mm X 3cm opening). The WIFI signals are coming in strongly in the 2.4 Ghz band but the FM signals are better attenuated by the enclosure. I am afraid I will have to throw away the whole enclosure and make a new one with only 3 5mm wholed, 2 for the 2 SMA connectors and a 3rd one for the USB connection.That is why for my home made SDR transceiver in VHF/UHF/SHF, I have decided to stick with the redpitaya and use discrete mixers (no integrated chip), local oscillators and band-pass filters in order to get a better rf performance in VHF/UHF/SHF than the one I could get with the AD9361/63 or even with the LMS7002. It's not going to be a compact set-up for sure but at least I will get decent rf-performance in terms of intermodulation and isolation. I will also be able to carefully chose the components myself to better control the desired rf-performance. I have done some preliminary tests at 2.4 Ghz using an IF of 50 Mhz, a LO of 2.35 Ghz based on a signal generated by an ADF4351 and using an 8 pole cavity bandpass filter designed initially for wifi channel 1 (much better performance than saw and baw filters). This set-up ate up space during my tests and I had wires everywhere but it performs MUCH better than my tiny plutosdr board; no intermodulation problem (ghost wifi and FM bands signals ) and no LO isolation problem when working in full duplex, no image rejection problem either. Moreover its HPSDR compliant which is not to be neglected.

author: Kalvin
author_rank: Super Contributor
timestamp: January 08, 2020, 02:40:34 pm
content: Have you tried adding ferrites to the USB cable and GPIO signals. The 2.4 GHz Wi-Fii will most probably sneak into the enclosure using the USB cable or GPIO signals. Check also that the seams of the enclosure are tight.

author: on7yi
author_rank: Contributor
timestamp: January 08, 2020, 03:29:21 pm
content: Indeed I still need to try all that before I decide to change enclosure, good point

author: on7yi
author_rank: Contributor
timestamp: January 08, 2020, 04:11:26 pm
content: I guess what I want to say is that I would be the first one to buy an integrated board based on the Zynq 7010 or Zynq 7020, with two physically distincts DACs and two physically distincts ADCs but no AD93X or LMS7X (for the lowest possible cross modulation between the 2 X input and 2X output ports), equipped with an SD card reader so it is able to run Alpine Linux and the open source software of Pavel Demin, with an ADF4351 to provide a local oscilliator synchronised with the clock of the FGPA and the ADCs/DACs and 4 discrete mixers (one for each port), then I would be the first one to buy that board provided that it is open-hardware. The programmation of the ADF4351, the filtering pf the outputs should be left to the end-user based on his user case.

author: OwO
author_rank: Super Contributor
timestamp: January 08, 2020, 04:40:09 pm
content: You would need either a very high speed ADC ($$$) (to use a high IF) or use a quadrature mixer (and use two ADCs per channel). The latter approach is more common because you don't waste ADC bandwidth. However the only good quadrature mixers on the market with good IP3 are ADL5380 and ADL5382, but they both require sine wave LO drive (datasheet doesn't mention this but it's in an appnote), otherwise shitty image rejection results. The ADL538x are NOT a good match for the ADF4351. You would need a switched filter bank of at least 4 filters to cover all the bands, but the mixer requires a differential drive so you have to either convert to single ended and back, or duplicate the filter bank (and length match everything). It's a shitshow all around. Yes, I investigated all possible ways to build a SDR (hint, the "5" in "sdr5" on my github is the number of major design approaches we've experimented with). In the end we decided the AD936x is the least evil and can be tamed with good shielding (shield cans over the baluns soldered on the PCB are mandatory) and pre-selectors, and gives best possible cost/performance in a constrained form factor and power budget.

author: OwO
author_rank: Super Contributor
timestamp: January 08, 2020, 04:53:24 pm
content: Let's see...-sdr1- this was back when I just started with electronics and PCB design, used a ad8348 quadrature mixer and two ADCs. Shitty choice of parts (ad8348 has bad IP3).-sdr2- really wanted good interference rejection so I went with a high IF approach to avoid the IP2 issue. Used two stages of downconversion because I couldn't build sharp enough filters. In the end the filters still ended up being too shitty, and with the way high IF receivers work there was no way it's going to be frequency agile so it's ugly all around and I scrapped the project.-sdr3- aforementioned ADL538x + ADF4351 + two ADC approach. Only realized after prototyping that square wave drive was unacceptable for the ADL5380, so this went nowhere.-sdr4- this was then I discovered the AD936x, and made a first attempt at a BGA board. It was a simple AD9363 + FPGA + USB PHY board, and worked well with GNU radio giving 30MB/s throughput over USB. Around this time I realized that you can't do much shit on an FPGA without access to lots of fast DDR memory, so I decided a Zynq was the only way to go.-sdr5- latest SDR design with Zynq + AD936x. You might think it's a pluto clone, but you can bet if the pluto did the job I would have just bought some plutos. The main differences are (as described on the GitHub):* Full 32 bits of the DDR3 are routed (for 2x memory bandwidth and 1GB memory)* Support for Zynq-7020 and Zynq-7010 in 400pin BGA package* Integrated RF frontends (LNA, PA, SAW filter) for two ISM bands (860/915MHz and 2450MHz)* Shielding* 4 layer board to reduce cost* SD slot for running real Linux distrosThere are 6 RF ports on the board, 3 rx 3 tx, or more specifically:* 1 broadband rx (no filters, all frequencies supported)* 1 900M band rx (SAW filtered)* 1 2400M band rx (SAW filtered)* 1 broadband tx (has a wideband gain block. AD936x tx power is WAY too low.)* 1 900M band tx (ACPM-7868 PA)* 1 2400M band tx (SE2576L PA)

author: 9aplus
author_rank: Regular Contributor
timestamp: January 08, 2020, 05:31:04 pm
content: @OwO following your SDR5, when ready really like to buy one sampleIn the mean time here fighting with of LimeNET micro...Just tested RX side with ICOM PCR1000 like 10,7 MHz IF/preselectorConclusion: Regarding RF what is possible with LimeSDR USB it is not necessary possible with mini or NET microRPI CM3 8GB is limiting factor, Soapy Remote is working with CubicSDR but not with SDRAngel, GNU radio is up and running.

author: on7yi
author_rank: Contributor
timestamp: January 08, 2020, 11:45:46 pm
content: Yes of course I saw the specification of your SDR5, pretty impressive and very professional, I like the idea that the pre-selectors are integrated on your board, and I would be happy to try it out should your board be available commercially or if there is a PCB assembly company willing to sell partially assembled board. It would be great if your board could be compatible with the software of Pavel that was writen for the Zynq7010 clocked at 125 Mhz and the Zynq7020 clocked at 122.88 Mhz and if that is not possible for design reasons, it would be great if it could be HPSDR compatible?All I am saying is that for ham radio experimental purpose, it is probably enough to obtain a very good rf performance in VHF/UHF/SHF, to have a simple non expensive board with a Zynq7010 and two pairs of DACs/ADCs clocked at 122.88 Mhz (so basically a redpitaya like set-up with a baseband of 60 Mhz ) but integrating on the board itself a local oscilliator (ADF4351 or something else) and 4 mixers (one per port). This would be simple cheap and would allow to easily experiment up to 2.4 Ghz provided the right external filters are used for the right use-case. The use of IQ mixers and doubling the numbers of DAQs and ADC etc... is all nice and great to save on filters, but do we really need it for our hobby ? It may not allow to easily build a multiband VHF/UHF/SHF transceivers as your sdr5 will allow do it it but it will certainly allow to obtain very good rf performance at an entry level on at least one VHF/SHF/UHF band at the time.

author: OwO
author_rank: Super Contributor
timestamp: January 09, 2020, 04:56:39 am
content: Yes, the high IF approach. If I can find an ADC that fast for a good price I'll certainly revisit it, since I have a bit more experience now and can probably design the IF filter without messing it up. (Back in the day I thought hand-wound small air inductors are the rage, since they have high Q and are "adjustable", but in reality they cross couple like crazy and completely mess up filter response and rejection.)You can use my zynq_som_2 (in the sdr5 repo) as a starting point if you want to design custom Zynq SDRs. It has all the DDR/power/USB stuff already and you just need to add the ADCs.

author: on7yi
author_rank: Contributor
timestamp: January 09, 2020, 11:30:39 am
content: No time to design a board for the time being, it will come after I retire in 10+ years or so. For the time being, I prefer to buy boards from gifted engineers like you and then limit myself to add the external components that are needed to obtain the best possible performance for ham-radio purpose.If you are going through the hassle of designing an SDR board based on the Zynq and the AD93XX, then why don't you go the extra mile and foresee a version of your board that is FULLY suited and optimized to needs of Hams ? By that I mean with selectable filters for ALL VHF/UHF/SHF ham bands in the input and output rf-pathes, and very important that delivers 30-35 dBm so the design of the external PA is simplified ? If you carefully think about it, we (Hams) don't have yet in VHF/UHF/SHF the equivalent of an Odyssey II, hiQSDR or Hermes Lite 2 board in HF. We are of course happy and grateful to have the LimeSDR , the Pluto etc.. but these boards have not been optimised for our specific usage. What is also important is to think of the software from the very beginning, look at the saga and the time it took to have SdrAngel work properly with the LimeSDR, better secure the support of your board from Edouart and/or Pavel from the very beginning of your project.Have a look at this project:https://github.com/xaxaxa-dev/vnaI assembled the "two port version" of that product from a spare PCB kindly given to me by the author and I was really impressed by the smd RF components that he chose and by his pcb design; the quality of the final product is quite outstanding in terms of dynamic range in the 2-3Ghz range (70-80dB) for the price paid.Looking forward to buy your board or to assemble it as an early adopter

author: OwO
author_rank: Super Contributor
timestamp: January 09, 2020, 12:53:13 pm
content: Yeah, sdr5 isn't actually intended to be a commercial product or a general SDR; it's an experimentation platform for designing modems, used for the development of OwONet which is going to be a physical layer optimized for wireless mesh networks. But If I end up with extra samples I might be able to send you one. Hopefully I can make some progress in this area this year; was busy with the S-A-A (NanoVNA V2) project for the last few months.

author: srce
author_rank: Regular Contributor
timestamp: January 09, 2020, 10:34:50 pm
content: Quote from: OwO on January 08, 2020, 01:54:06 pmWhere are you looking? Digikey has LMS7002 for £83, whereas AD9363 is £92 and AD9361 is £213.Price aside, how would you compare the two?

author: pipe2null
author_rank: Regular Contributor
timestamp: January 10, 2020, 01:22:33 am
content: OP's $0.02:+1 for OwO's sdr5, I would have bought one (or more) if it were available for purchase.For the original intention of the thread: With all the feedback y'all have given (thank you all again!), I've refined my intended use and initial SDR related projects quite a bit, so I have specific uses for all three SDRs within the next month or two depending on how much time I have for different projects. I ended up buying an RTL-SDR Blog v3 kit, a LimeSDR, a LimeSDR-mini, plus a grab bag of LNAs/filters/(RP-)SMA adapters and cables. Plus a cheapo $15 RF noise generator to get a crude idea of the frequency response of DIY filters. There is a pretty good chance that I'll also end up with an SA-TG or a VNA (single path) in the not-too-distant future...FPGA wise, I finally did enough reading to get a general lay-person's overview and determined that I really should (need to?) build FPGA dev experience. I seriously looked at buying a $600 Chinese knock off USRP B210, but I have the impression you have to have a commercial software license to code for the Spartan 6 XC6SLX150? Either way, it makes sense to me to target something that includes ARM core(s) like the Zynq on a device that also includes an SD card reader for a full OS. I skipped the pluto due to all the problems I keep hearing about, plus it is SISO.@OwO: There seems to be a really big gap in the RF/FPGA capability of available (remotely affordable-ish) SDR models between those on +/- par with LimeSDR and those models similar to the USRP embedded series (B310 etc). I ended up getting the LimeSDR for messing with MIMO but more in the hope that there are enough available FPGA logic cells/resources available to do something "useful" from an FPGA beginners point of view (and NO, toggling an LED is NOT "useful" to me... Heh), but it does not have the headroom I wanted to grow into as my skill and experience increases...So: A second +1 for your sdr5!

author: srce
author_rank: Regular Contributor
timestamp: January 10, 2020, 09:56:26 am
content: Quote from: pipe2null on January 10, 2020, 01:22:33 amFor filtering and more power for the Lime SDRs, you might want to look at theLimeRFEwhich is just about to be released.

author: 9aplus
author_rank: Regular Contributor
timestamp: January 10, 2020, 10:07:26 am
content: LimeRFE is on the market since mid 2019.For my taste to much $$$ and still lack of SW support.

author: srce
author_rank: Regular Contributor
timestamp: January 10, 2020, 12:03:13 pm
content: Yep, it is pricey - but may be a useful reference point it you want to create your own cutdown version, as the schematics and layout are open source.

author: radiolistener
author_rank: Super Contributor
timestamp: January 16, 2020, 05:55:56 am
content: Quote from: OwO on January 09, 2020, 12:53:13 pmOwO, did you think about simple DDC SDR based on 16 bit ADC + FPGA + 14 bit DAC?RF frontend can be done just with RF transformers (like Minicircuits TC4-1T), with two SMA connectors.It can be implemented as a module with ability to install low phase noise crystal or TCXO option.Such module can be used as DDC SDR receiver just out of the box, as DDC/DUC SDR transceiver, as a spectrum analyzer or vector network analyzer. With working bandwidth 0-61 MHz. It will be very popular for good price.In addition it can be extended with external expansion board with down-converter for 100 MHz - 6 GHz range. And power amplifier module. Also STM32 module with touch display can be attached to use it as a portable transceiver. Amateurs can use it to develop their own gateware and firmware. And such module kit will be a nice solution for SDR.Such product on taobao and aliexpress will be a big step forward from current rtlsdr and hackrf things. And the price will not be expensive, it can be below 100 usd.The gateware can be based on open source openhpsdr Hermes or Metis project:https://openhpsdr.org/hermes.phphttps://github.com/TAPR/OpenHPSDR-FirmwareThe software for PC is already here, for example PowerSDR, HDSDR, and many other.As I know you're working on the team who develop different RF things. It will be nice if your team start to selling such modules. The main goal is to make cheap and simple SDR with impressive parameters. DIY kits for that will be even greatWhat is your thoughts?

author: radiogeek381
author_rank: Regular Contributor
timestamp: January 17, 2020, 03:19:07 am
content: I'm a little late to this discussion (perhaps too late), but....I've been developing software for the Ettus USRP series for 7+ years now, and have never found the need to do any FPGA modifications. One can cover a whole lot of DSP learning and serious applications with the Ettus UHD library or GnuRadio.The USRP entry price might be daunting. (My daily SDR is an Ettus N200 with a UBX40 module, this is a $2K+ adventure. But I also have a B200 that is quite useful.) On the other hand, the software support is very good, the library is professionally written and maintained, and the engineering and manufacturing are commercial quality.My N200 has been used as an IF radio for 10GHz contests since 2012. It has bounced around in the car, been dragged up hills, over beaches, and onto roofs. The case is witness to the traumas, but the radio works very well after all these years. In between 10GHz contests, the N200 is on HF 24/7 as a WSPR beacon/receiver.I'm running a software defined all-mode transceiver program (SoDaRadio) that works from HF through the microwave bands. No custom FPGA hardware, all the "magic" is in the software running on the linux host -- IF conversion, filters, demodulators, modulators, resamplers, and spectrum displays.For those who need to build FPGA custom logic, the USRP software suite supports the RFNoC (RF network-on-a-chip) framework. Again, I suspect there are many FPGA customization projects that would be better off figuring out how to perform the function in software. But, most of the USRP models provide RFNoC support. All allow some FPGA customization.Finally, the USRP series was originally developed as a platform for GnuRadio, and much of the current development of GnuRadio continues to involve Ettus engineers.

author: radiolistener
author_rank: Super Contributor
timestamp: January 17, 2020, 08:35:17 am
content: Quote from: radiogeek381 on January 17, 2020, 03:19:07 amFPGA is needed for the function which is cannot be handled in software, because when ADC working at 122 MHz with 16 bit output, there is a 2 Gigabit realtime data stream which cannot be processed in software even with powerful PC. The goal of FPGA is to produce IQ sinewave (LO) with low noises in digital domain, mix it with input data stream and apply low pass filter and decimation. In such way FPGA reduces data stream with high quality down conversion which is not affected with images and mirror channels. All further processing is done on PC in software. Of course it can be done on FPGA, so PC will not be required, but software processing on PC is more flexible.FPGA just allows to implement most heavy math processing part in hardware, so calculation will works extreme fast, much faster than very powerful PC can do.

author: mallets
author_rank: Newbie
timestamp: January 18, 2020, 07:02:31 pm
content: QuoteThis hasn't been my experience using bladeRF(V2, AD9361) and GnuRadio. Selecting a 1Mhz channel from an incoming 40 MHz I/Q stream (which is close to a 1280Mbps data stream) hardly pushes my old quad core CPU, this includes generating a digital LO, multiply and a simple LPF + decim block. Most of these blocks can be optimized even more, like pregen. lo samples and simpler filter taps. Also, most recent RF chips and high speeds ADCs/DACs now include NCO + decimating/interpolating filters so you can just work only on the data you are interested in. I think people really underestimate modern CPUs when it comes to DSP. For fast DSP, check outKFRLIB. Hell, a raspberry pi 4 seems capable enough to do all the above and then some. Only downside to software processing is the unavoidable latency imo. That too is mostly due to the USB + FIFO buffers RTT. And software like SRSLTE can run a LTE base station off consumer hardware.

author: radiolistener
author_rank: Super Contributor
timestamp: January 18, 2020, 07:31:34 pm
content: Quote from: mallets on January 18, 2020, 07:02:31 pmAD9361 already includes down converter circuit and produces IF on the output. But if you use DDC with usual high speed 16-bit ADC which working at 122 MHz, it produces on the output 122 megasamples per second each sample 16 bits length. In order to process it, there is needs to produce 122 MHz I/Q LO, mix it with input 122 MHz stream and apply filter and decimation to 122 MHz I/Q stream.The data flow from the ADC is 244 megabytes per second. It means that PC should produce LO sine wave stream with about 732 megabytes per second. Mix it with input stream which is 244 megabytes per second and apply filter to the result stream which is about 732 megabytes per second. All this should be done in realtime and it doesn't include demodulation, this is needed just to produce IF data stream which is needed for SDR software. PC is unable to handle so crazy data flow in realtime. This is where FPGA is used to handle it. Even for FPGA this task is too hard.After DDC IF consists the data stream with I/Q at about 1-20 MHz sample rate. It can be easily processed on PC with SDR software.So, the main goal of FPGA here is to reduce data flow from crazy 122 MHz x 16 bit taken from ADC to usable 1-20 MHz I/Q stream, which can be used for SDR software processing.

author: radiolistener
author_rank: Super Contributor
timestamp: January 18, 2020, 07:48:00 pm
content: Quote from: mallets on January 18, 2020, 07:02:31 pmthese RF transceiver chips usually using 12 bit ADC with mediocre specification. Also they using noisy NCO. So, you will get typical worse performance of the TV dongle with noises, images and spurs...If you want to get the best specification, you're needs to use dedicated high speed ADC clocked from low phase noise oscillator... Also it requires FPGA to implement good LO NCO and DDC. In such way you will get much clean output with less noise, no spurs and better dynamic range.And this is where is difference between cheap SDR dongles with low specifications and professional SDR DDC/DUC equipment with high-end specifications.Quote from: mallets on January 18, 2020, 07:02:31 pmThe downside is worse dynamic range and IMD. Also it has noisy and spurious NCO for LO, so the output consists of higher noise, spurs and images which are missing on the input signal. It is acceptable if you want just a simple LTE base station. But if you want to get receiver with the best specification, you will needs to use dedicated ADC.

author: OwO
author_rank: Super Contributor
timestamp: January 19, 2020, 05:50:39 am
content: Downconversion is a very simple task which takes about 2% of the multipliers in a Zynq-7020 and even less percentage of the fabric. If designed well it can run to 300MHz easily. GNU radio struggles to downconvert a 20Msps stream on my i7 laptop with 7000 passmark (it can do it, but pegs one core and gets the CPU fan to maximum). The rest of the DSP that I need to do for wideband communications (FFT for OFDM, FFT + brute force search for DSSS, etc) are where most of the work is. IMO the "software" in "software defined radio" is what's keeping it back and preventing it from being adopted in real world commercial applications, and it should really be called "reconfigurable radio" from the beginning instead.

author: radiolistener
author_rank: Super Contributor
timestamp: January 19, 2020, 09:08:29 am
content: Quote from: OwO on January 19, 2020, 05:50:39 amyes, it's simple for typical NCO with spurious and noise performance at about 100-120 dB which is acceptable for typical 12 bit ADC receivers. But for 16 bit ADC these noises become very annoying and significantly degrade ADC performance. High dynamic range NCO needs a lot of table memory. Good FIR filter with high dynamic range, running at 300 MHz needs a lot of hardware multipliers and fast enough FPGA. CIC+FIR leads to worse dynamic range and bad image performance, especially when decimation ratio is not high enough (let's say 5-20).For example, here is response across all filters in DDC receiver on FPGA (ADC clock 61.44 MHz, CIC+CIC+FIR):What is the noise floor and spurious performance of your NCO, what is decimation rate and type of LPF and it's attenuation which you're used on Zynq-7020? I tried to design DDC which will be acceptable for my case (I want to get about 130-140 dB performance with no spurs, no images and low noise from DSP), but it looks that this is very hard or even may be impossible with cheap Cyclone 4 or Cyclone 10LP FPGA, due to lack of resources...I want to get something like that (this is real FIR response):OwO, what do you think about FPGA+16 bit ADC (at 122.88 MHz)+14 bit DAC module for selling on the market? I think, with a good price it can be the same popular as NanoVNA project... It needs minimal RF front-end, impedance match to 50 Ohm can be done with RF transformer for better noise figure... So, the total price should be pretty low.

author: OwO
author_rank: Super Contributor
timestamp: January 19, 2020, 12:47:07 pm
content: This is the filter response of one of the channelizers I used (this one is for FM):~1000 taps, 1% bandwidth, 18 bit coefficients. The filtering/decimation has to be done in one step (no multiple stages) because of the architecture used (first a window is applied to the input, then a FFT is performed to split into channels), but with this approach you get 1024 channels for the cost of one coefficient ROM, one coefficient multiply, and a 1024-point FFT. The channels can be overlapping to ensure no aliasing. The same amount of FPGA resources can barely implement 8 channels with the traditional approach of downconversion then FIR filtering. You could have more filter rejection by going to 25 bits coefficient, but the FFT that follows would also need to use two DSP48 per real multiply to get 25 x 35 multiplies, which would implement 25 bit twiddle and 35 bit data. That would be something like 34 total DSP48s for 1024 channels, which is 15% of a Zynq-7020.I'm most likely going to be designing a 14 bit ~100Msps high-IF SDR, unfortunately no 16 bit ADCs for now because they are way out of budget. To get a reasonable price break with one of the major manufacturers will require at least 1k units/month, which something only covering HF will not sell anywhere near enough. I'm not going to commercialize this project, but expect some open source designs using cheap ADCs.

author: OwO
author_rank: Super Contributor
timestamp: January 19, 2020, 01:42:47 pm
content: And this is the actual performance of the channelizer as a whole with 18 bit coefficient and 17 bit FFT twiddle, in vivado simulation:The channelizer is being driven a full scale sinusoid. The graph seen here is a listing of the output channels. The overlap factor is 16 so the sinusoid falls into the passband of just under 16 channels (passband % of nyquist is determined by the filter coefficients). The peak noise/spur floor is 10dB so the minimum dynamic range is 107dB. This is mainly bottlenecked by the FFT twiddle size, which has to be 17 bits to be able to fit into the 18 bit multiplier without errors. If you use 2 DSP48 per multiply you can get 24 bits twiddle.EDIT: in this use case (which was used with sdr5 for recording many FM stations at once) the decimation factor is 1024/16 = 64. The input sample rate is 20.48MHz (I/Q) and the channelized sample rate is 320kHz (also I/Q). The passband is 180kHz wide. The channel pitch (spacing) is 20.48/1024 = 20kHz.The window multiply and FFT are running at 20.48 * 16 = 327.68MHz. There is a "channel selector" afterwards so that only selected channels have to be written to DRAM. For higher sample rates the overlap factor can be reduced, which means coarser frequency step but narrower channels.

author: chris_leyson
author_rank: Super Contributor
timestamp: January 19, 2020, 02:36:18 pm
content: Philip Covington (N8VB) launched the QS1R SDR about ten years ago, uses LTC2208 16-bit ADC and Cyclone III for the backend processing. QS1R is no longer manufactured I think partly because a Japanese gentleman purchased two receivers and the front end design has now become part of the ICOM 7300 allegedly.https://www.eham.net/forum/view?id=topic=117125.15It's a shame because the QS1R is a nice receiver. The Verilog source is available for those who are interested, sorry can't find link my googlefu isn't working today. Backend uses a pair of CIC filters followed by FIR filters and I think the CIC filter word length maxes out at 128-bits.I like OwO's approach using FFTs for the filtering would be a useful exercise to try it out in Matlab/Octave. FFTs have to overlap-add or overlap-save.I think if I was building something from scratch I would base on the QS1R frontend followed by LTC2208 and a Zync FPGA.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 19, 2020, 09:01:21 pm
content: Quote from: chris_leyson on January 19, 2020, 02:36:18 pmI have a QS1R and I also have a local saved copy of the FPGA source. It's a bit too big to post here but I guess if anyone is interested I could find a way to share.

author: OwO
author_rank: Super Contributor
timestamp: January 20, 2020, 03:23:10 am
content: I would like the QS1R HDL sources.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 20, 2020, 06:42:12 pm
content: Here's the download link (14MB):https://drive.google.com/open?id=1-VNvkPUesYm4ZxJaJRJpXitoWBdJVn6O

author: julisdr
author_rank: Newbie
timestamp: January 29, 2021, 07:13:40 pm
content: Hi OWO,I'm very interested in the sdr4 board since it's more adapted for what I have in mind (mix it with a jetson nano for gpu procesing) but don't know if it's available for purchase even or finished. it seem from the github project that only the RX part is done since in picture only the rx chain is soldered.Have you plans for sell it?. if not I'm considering to made my own with a cheap AD9363 from aliexpress for saving money since the price for official distributors is more than the rest of the board!! .¿any advice?.Thanks.

author: Gerhard_dk4xp
author_rank: Frequent Contributor
timestamp: January 29, 2021, 09:59:54 pm
content: Quote from: on7yi on January 08, 2020, 12:35:16 pmI'm working on a 432 MHz transverter for the RP. No-tune with SAW-filters, PIN attenuator, crystal oven, 17 dBm ring mixers, 0.5W tx power, F=0.6 dB currently. The SKY 67150 eval board delivers 0.3 dB. No idea why mine is worse. I have even swapped parts with the eval board. Must be the Rogers layer.The 100 MHz crystal oven is multiplied twice, IF for 432 would be 32 MHz. There is a 100 MHz outputfrom the oven to feed the Red Pitaya ADC. Makes no sense when the transverter is stable and the RP is not. There is also a tuning voltage port to the oven, so I can lock it to GPS or whatever.The board is just 2.5 * 2.5" in size, but will need at least another respin at JLBpcb.When done, I'l describe it in DUBUS.