@jherbert I didn’t mean to criticize u.Fl connectors in general, just saying that there may be a good reason why one adapter cable costs $10 why the other only costs $2. I got a “bare PCB” LimeSDR and so it is quite inevitable that I will be taking the cables on and off a few times until it comes into an enclosure.
I see. I just ordered ten of these in China for about 8 Euros. I will leave them on the board and use the smas to connect wherever is necessary. So I don’t see any problems there. I also had ordered an Antenne kii, which I probably won’t need.
Where did you order the antenna kit?
I ordered the 4 antenna kit from crowd supply.
The chinese vendor is 10pcs cable SMA female bulkhead jack to IPX U.fl PCI card 1.13mm 6" pigtail
Hi Simon, I’d just like to clarify that these are the schematics for the boards that people will be receiving and are not a special version done for GSM development. Not sure where you got this idea from?
Guess it was wishful thinking. 
I had hped for a board I can use on shortwave bands. That hope is gone now. very frustrating.
I asked whether the filters would be present on the boards we’ll receive and was told they would not. Selling boards with the filters in place but advertising a frequency range covering up to 3.8GHz is very naughty as the filters compromise the range. What use would the boards be for radio amateurs with the filters in place?
If the filters will be present then I’m definitely not interested in the long term unless I can find a way of removing them.
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If you look at https://www.crowdsupply.com/lime-micro/limesdr then clearly there’s a conflict if the filters are in place:
Here are just some of the applications that are possible with the LimeSDR:
• Radio astronomy
• RADAR
• 2G to 4G cellular basestation
• Media streaming
• IoT gateway
• HAM radio
• Wireless keyboard and mice emulation and detection
• Tire pressure monitoring systems
• Aviation transponders
• Utility meters
• Drone command and control
• Test and measurement
Any chance someone could post a wide-band frequency response curve for each of the receiver inputs (Low, High, and Wide) so we could see what response to expect? This information would answer a lot of questions for us. Thanks!
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I can’t give you a curve but signals on 88-108MHz are at least 15 to 20dB down compared to the AirSpy, so there will be some mass removal of components when the boards arrive. Problem is, these are as small as fly droppings!
A nice after-market add-on would be a series of saw filters maybe.
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My personal interest in the limeSDR which prompted my purchase is for HF /VHF and UHF amateur radio use including diversity combining to steer a null in an array at HF using two receive inputs and phase combining in software. I also have a professional business interest in the hardware for satellite communications modulator / demodulator use which I was going to contact Lime Micro on . In both cases the mobile basestation specific Bandpass filters added to the low noise RF front end will make the board unusable for these applications . As referred to by Simon the broad range of uses described in the Lime Micro marketing material for this board and some associated quoted specifications are misrepresenting the product and clearly have misguided a large number of the people including myself who collectively funded the next steps on the mass market commercialisation of this product. I recommend that the Product Managers at Lime Micro / Myriad have a re think about the inclusion of these band limiting filters on the main board and consider their inclusion ( as well as other application specific Bandpass filters ) as a range of optional sub boards including a broadband bypass no filter option or as part of the low noise amplifier boards they are developing .
Best Regards
David Price , CEng MIET , PA4MSA
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David, Simon, et al.,
I’m a member of the RASDR radio astronomy group, and have used myriadRF (with LMS6002D transceiver chip) for radio astronomy (amplitude and spectral work, observing hydrogen at 1420 MHz). With the 6002D chip, we use the wide-band, 10dB noise figure internal LNA, together with an external low noise LNA very successfully for radio astronomy, even with relatively small antennas. Thus the LimeSDR (with LMS7002M), having (lower) 5-7dB noise figure input should work well for a variety of applications. One also has benefits from on-board decimation, DSP, etc. These SDRs just need a low noise-figure preamp, and sometimes a bandpass filter. For HF, I suspect that a prefilter for QRM will be more important.
I want to extract the audio chirps from meteor bounce signals in a couple of weeks. Anyone know how to do this, beginning with FFTviewer, or with the Windows software in the LimeSuite?
Thanks,
David, N4HBO
David,
With my software you can do this - either:
- send audio to a Virtual Audio Cable and then to the software of your choice, or
- just record the audio output (to be added soon).
When you have a LimeSDR board I can give you a private build - same as Marty has.
SKYPE: sdr-radio.com
Thanks for your observations on FM broadcast band signal levels, that’s really unfortunate! Regarding modification, in addition to removal of tiny components (which is hard enough), one will probably need to add a jumper which will be even more tricky. This user modification of the LimeSDR is a risky proposition. It’s quite possible that one could wind up making their LimeSDR unusable (damaged circuit traces, etc.). At the moment, the choices are either settling for somewhat degraded performance at most frequencies or attempting a risky modification. Having frequency response curves (or tables) would allow users to decide whether the current design is adequate for their needs.
Hi,
Here’s a photo of the board, the filters are between the connectors and the Lime chip. Good luck!
Like you, I don’t want to modify the circuitry myself. If performance is inadequate (for me) AND Lime Microsystems offers no factory modification option, I would be inclined to sell it rather than risk modifying it myself. Once I receive it I will decide whether it meets my needs.
Chuck,
Let’s wait for the powers that be to make a decision - if the filter is indeed part of the shipped board then there will be some very unhappy customers, also I recommended this board to users of my software, so I’ll not be the most popular programmer in town 
. Myself I’m sure I must know someone in the industry who can modify the filters.
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I don’t think anyone “wants” to modify the board, but I, for one, would be much happier if I had quasi-linear frequency response from the board itself, allowing me to decide what filters and for which bands to add, so I will modify the board if there’s no other option.
Now the problem about modifying and really getting the wide bandwith (as advertised) with reasonable linearity is - as I see it - that someone competent has to design the modification. It would be great if the good Lime folks would do that, but so far they - quite curiously - seem rather privy about some key aspects.
Surely the design files are there, for everyone to see, but I think it would have been reasonable to openly state, on the front page, that there are certain limitations - by choice, especially if the frontline says 100 kHz – 3.8 GHz.
It starts feeling a little uneasy, but I guess we’ll see…
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It is an interesting point of reference that Lime Micro is also marketing a set of standalone SAW based Bandpass filters for the mobile basestation bands . As stated about this is IMHO the right way to go . Ie maintain the broadband flexibility of the Lime Micro radio transceiver chip on the Lime SDR board to address the largest market use and provide the necessary input Bandpass filtering for a specific end use using a range of selectable standalone passive filters to be connected at the input to the board . Examples of filters already marketed by Lime Micro Are shown via the following link.
https://myriadrf.org/blog/new-rf-front-end-modules-project/
Food for thought ?
David Price. , CEng , MIET , PA4MSA
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There extra modules are very exciting (horrible expression), especially the LNA.
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