Where did the 100 KHz go?

I would think that a WBC2-1TL could work well … if it is the same size as what is used in RX_W (TC1-1-13MA – 4.5Mhz to 3GhzHz) …

I use a WBC2-1TL (200Khz - 500Mhz) in a UHFSDR and 1.79Mhz Rx is no problem …

They are not quite the same size … but i bet it would fit …

You can remove 10nH coil at RC_W input and using original transform

I’m glad I’m seeing this conversation now rather than when I drop nearly €400. Getting a refund from a crowd-sourced project is pretty much impossible.

Dear Andrews
Your article from the 18th February, 2014

LMS7002M announced and new module in the works
By Andrew Back
18th February, 2014

Last week Lime Microsystems launched their second generation field-programmable RF (FPRF) device, the LMS7002M. This improves on the tried and tested LMS6002D by providing a dual-transceiver which is 2×2 MIMO capable, with frequency coverage extended all the way down to 50MHz, and that is based on a 65nm CMOS process which gives reduced power consumption.

Just a few of the key features of the LMS7002M include:
• Continuous coverage from 0.05-3.8GHz
• Programmable RF modulation bandwidths of 0.1-108MHz
• Transceiver Signal Processor (TSP) integrated between digital converters and IQ interface
• 550mW typical power consumption in full 2×2 MIMO mode

For further details see the product page, which includes a link to a comprehensive datasheet.
As with the LMS6002D, Lime will be making detailed documentation for system designers available without the need for an NDA, such as a programming and calibration guide.

Are you, the creator and the builder
You specify above: “Continuous coverage from 0.05-3.8 GHz”
My LimeSDR is not delivered so you can easily make the appropriate changes to the product

I have never ordered a LImeSDR for optimum reception at 700 MHz!
But i placed order for a LimeSDR coverage of 100 KHz to 3.8GHz

I expect from you a fast solution so that the LimeSDR can operate in reception and in good conditions in the part of the spectrum HF from 100 KHz and that on two inputs of reception

Bernard MALET

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Hi @Bernard, an update is in progress and repeatedly posting the same and similar remarks at different places across the forums is not helpful. Thank you in advance for your patience :slight_smile:

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Just a reminder of what Lime Micro promised in terms of broadband gain and NF performance on the 1.4 boards

They need to confirm whether they are meeting this offer spec.

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Yes, just cancelled my pre-purchase with crowdsupply. Money was refunded!

It is planned for when the diagnosis and the modifications to make, to obtain the 100 KHz?

I’d like to get a feedback on this as soon as possible as well. I suppose this information will help me decide whether to keep or cancel this order.

Considering their fulfilment centre is in the US we’ll all be better off if we cancel instead of returning it.

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The main reason to cancel rather than return is that from what I can see, crowdfunding is not the same as buying. The same ‘fit for purpose’ and sales description legislation doesn’t apply, as you didn’t buy something, you invested in a company and got a reward for your investment.
This is just my interpretation, but I have seen a number of cases that support this.

From a very Helpful Crowd Source Email that I received yesterday, 8th Feb. It explains that Lime are looking into the subject and also some options. Thank you to both Crowd Source and Lime for the information.
I was in touch with the team earlier today about this very issue and
they are looking into the reported change in frequency range. Their
initial guess that the report is incorrect due to some sort of set up
error and they intend to update all backers with their findings soon.
They only found out about this report yesterday and are working
quickly to get to the bottom of it. Your order is likely to be shipped
in by the end of next week, if not this week. If you’d like, we can
hold your order until the LimeSDR team posts their update. Of course,
it’s not a problem to cancel your order now as well. Please advise.

Quick Question … and this is just in theory …

the Lo lowest settable freq is 50Mhz ?
The ADC bandwidth is 56Mhz or so …

Then in theory, the LimSdr could Rx audio down to DC if there was no DC decoupling …

I wonder what is “Extended by TSP NCOs” exactly …

A quick update:

Lime engineers have done tests to compare v1.2 and v1.4 hardware — using @SimonG4ELI’s software — and found no difference in performance. If anyone has both those hardware revisions and is seeing a difference, all we can assume is that there is a configuration error.

Performance with v1.4 boards should be the same as demonstrated with v1.2 boards during the campaign.

A more detailed update, with measured performance and recommendations for optimising the performance below 100MHz, is forthcoming.

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Andrew,

What configuration settings are we capable of modifying beyond what SDRConsole allows us? I have PIA, TIA, and LNA gain settings at max and have also tried different combinations that are max’ed out to achieve similar results to my V1.2 board - to no avail. Are there other gain settings ‘under the hood’ that we should know about now so we can correct these errors?

Please advise at your soonest with that info - I’d like to see a baseline with my V1.2 board if there is a way of adjusting it either in the open or ‘under the hood’ so I can report this, too.

73s de Marty, KN0CK

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Screenshots of the software would help I think.

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@andrewback is this valid for all receiving ports? Or is this only for RX1/2_L and RX1/2_W?

So I guess now the proper question is if someone has confirmed (can confirm) good performance at low frequency with LimeSDr 1.2 and Simon’s application?

Also @andrewback as you seems to have properly working LimeSDR 1.4 + Simon’s Console app I think it can be used as a reference if you don’t mind providing some data to a community?
Can you please describe your exact RF test setup?

Thanks
Dimitar

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I didn’t do the testing — that was left to people far smarter than I and with access to much fancier test equipment :slight_smile: But as I say, data is forthcoming.

@SimonG4ELI good idea, I’ll request screenshots.

@martywittrock can remind me where you shared details of your experiences with HF and v1.2 hardware. I seem to recall you were happy with the performance at the time and, based on general feedback from beta testers, I understand the decision was made not to change the matching networks from what v1.2 boards had.

In this post

@RicardasVadoklis said that:

Currently we are using components on LNA inputs to fine tune for some cellular bands. On the final version of the LimeSDR we shall match the receivers for the optimum broadband performance.

But they did not remove the components on LNA inputs from v1.2 to v1.4. Am I correct?

No @andrewback, @Bernard is right. I received my LimeSDR (v.14s - sadness) today, and a few hours later I found this thread… Like @Bernard I placed order for a LimeSDR coverage of 100 KHz to 3.8GHz. It seems to me that the problem is hardware, and not just configuration. We are talking of the input filters and these are not changed by software, isn’t it?

Obviously I have no way to change the filter components (SMD stuff), so I nearly quote @Bernard and I expect from you a fast solution so that MY LimeSDR can operate in reception and in good conditions in the part of the spectrum HF from 100 KHz and that on two inputs of reception.

I hope to have news soon…

I did mentioned on the other subject that there is no filter on the RF ports at all. There are 1:1 transformers with the matching network and there is a pair of RF switches. The design is OK and according to the LMS7002 evaluation board. The transformer used is a good approach and I do not suggest to remove it. The data sheet does not show clearly the transformers performance down to 100khz but from the graphs, there should not be a problem using them also on low frequencies.

I download the S parameters from the manufacturer and just by quickly looking the figures it seems that used transformers are good from 1Mhz. There is a data starting 300khz up to 4Ghz and it is complex as this is a 4 port device.
I may try to simulate the performance together with the matching network to get the picture how it looks like but this is probably done by designers and they should have the simulations with the S parameters, i hope they have used such approach. This will save me or others from spending time on simulations.

It is strange that Simon has the problems on 100 Mhz, so it may lead to the sw configuration problem rather than hardware problem. The fron-tend is so simple that there is not much to do around it.