For those interested in using their LimeSDR on frequencies >3.8Ghz:
150 units only
So… is there something I don’t understand or basically LimeSDR + LMS8001 board does the same USRP B210 does but better and much cheaper?
as the datasheet say up to 10 GHz but for the most hobbyist the 10 to 10.5 GHz Band is quite important so is it possible to use this chip a bit “out of spec” or do we have to look for an other solution.
The interesting thing is later in the application example it says if I read it right that if only one Chanel is used the chip than somehow capable to go up to 12 GHz.
Measurement updated — see Chapter 7:
I’m also told that:
With modification in the matching components on the board it would be possible to reduce the RX gain variation and improve the NF for the 10 - 10.5 GHz band to some extent, if needed. The TX performance in 10 - 10.5 GHz are not likely to be enhanced. The PLL inside the LMS8001A chip operates with no degradation up to 8.3 GHz, and with some degradation up to 9.2 GHz.
However, initial versions of the LMS8001 are specified for up to 10GHz use due to the packaging.
Well, if I got this measurement document right it means that you can shift 1-3 GHz signal from LimeSDR only into two predefined bands: 5 GHz or 10 GHz (and vice versa), but any other frequency (say 7 GHz) would require modification of matching networks on LMS8001 Companion board in order to get decent performance. That does not sound flexible
Andrew, after your reply above I am still not certain of the answer to DL4APT’s question:
- Will the unit work for receiving at 10.5 GHz?
- Will the unit work for transmitting at 10.5 GHz?
I had ordered two units but will cancel the order if the answer is no. There is amateur radio spectrum at 10.368-10.369 and if the unit is not usable in that band then it has no use to me.
Thanks in advance for your reply!
I asked for clarification and was advised:
Measurements show (as provided in the documentation) that for downconversion (receiving) at 10.37 GHz down to 2.5 GHz the approximate performance is:
Gain = 7.5 dB, NF = 14.5 dB, Input IP3 = 10 dBm, Input 1 dB compression = 0 dBm
For upconversion (transmitting) 2.5 GHz to 10.37 GHz:
Gain = -13.5 dB, Input IP3 = 15 dBm, Input 1 dB compression = 7 dBm
So it works, it shifts the signal in frequency, but it depends on the application if performance would be good enough.
This is without modifications to the board. As mentioned, the receive performance might be improved to some extent by changing the matching on the board.
What is estimated retail price of the LMS8001A IC alone?
It’s not been announced as far as I know and I genuinely have no idea.
Thanks Andrew for the very nice clarification note. It is just what I needed to know and means to me that I can use the Companion for my application.
I am looking forward to receiving the Companions in the mail next year
Great, can’t wait to hear about your project(s) using them!
Following from the comment by CCSH item6: and the information in https://github.com/myriadrf/LMS8001-Companion/blob/master/docs/LMS8001A_Companion_Quick_Starter_Manual.pdf
It appears that: The Evaluation board is designed such that it converts fRF = 5-6 GHz (which is referred to as 5 GHz band) or fRF = 9-10GHz (which is referred to as 10 GHz band) to FIF – 1-3 Ghz in down conversion and vice-versa. And Channels on the evaluation board are set as follows Chanel A – Up-conversion – 10GHz band; Channel B – Up-conversion – 5 GHz band; Channel C – Down-conversion 10GHz band; Channel D Down-conversion – 5GHz Band.
The main description indicates” The highly integrated, four-channel frequency-shifter can be used with all variants of the LimeSDR – from Mini and USB, to PCIe and QPCIe – to extend their frequency coverage up to 10 GHz. “ but does not indicate this to be limited to two 1GHz ranges.
It is unclear to me is the document above simply describes two examples and the board actually has adjustable contiguous coverage as indicated in (https://github.com/myriadrf/LMS8001-docs/blob/master/LMS8001A-Datasheet%204.0r4.pdf ) to 10Ghz or if it is limited in its ability to up/down convert frequencies to the two stated ranges through its implementation on the test board and has no capability between 3.3GHz and 5GHz or between 7 and 9 Ghz without re engineering the matching circuits. I have submitted a pledge and am looking forward to being able to experiment with the board but if it is limited to only two 1GHz ranges I would request your consideration of cancelling my pledge as it would not meet my use case.
Looking forward to your clarification. Cheers.
Plots for “Conversion Gain (2.0 – 11.0 GHz)” for each channel have been added to the “LMS8001 Companion Board Quick Starter Manual” in Chapter 7.
Thank you Andrew
Reading that we can understand that
For up-conversion TX
channel A is useful from approx 8,5 to 10,5 GHz
channel B is useful from approx 3,5 to 6,5 GHz
And for down-conversion RX
channel C is useful from approx 9,5 to 10,5 GHz
channel D is useful from approx 4,5 to 6,5 GHz
All with no modification of existing RF networks.
My opinion is that one who need more flat wideband solution can use
some of DBM mixers from WJ or for example
Anaren 74127, freq GHz / IF, 2.5 - 10 GHz / DC - 1500 MHz
all with proper inband or wideband LNA and proper LO
All that cost much more and can not be packed in small case,
the same old: there is no free lunch, story
I was one of the first backer s of the lime but became pretty frustrated once I bumped into the limitations posed by the “matching networks”. Sold the board and just check in for news once in a while. Seems the machting network issue (which obviously is a non issue for lime) is carried over to extension products. Too bad.
I wonder why lime did not choose a more modular approach: Have all the functionality on board and put matching networks on a piggyback board, mayby even in a way that let us use standard components to grow our own. But am not an engineer then.
Modular approach with networks on that freq (above 1 GHz) is more level of black magic than
That makes perfect sense.
i would like to get such a board … but have no credit card …
any chance to add paypal to the list?!? … then i will order one
Please contact Crowd Supply.