Modification HF and new TAXES
A very important point, Andrew
Having already encountered this problem, at another supplier during a free of charge replacement of material from the USA.
My provider had returned the material Free of Charge, but had mentioned the value of my first purchase.
The Customs of my Country has made me pay a second time this material yet Free of Charge.
So for your customers to return from the hardware modification not to mention hardware value
If not your customers, for the return of this modification, will pay a second time the Entry Fees on their Territory
Best regards
Bernard
To avoid the 6 weeks minimum of extra time I will make the same modification myself
Nota: Still no answers to my order date request for my order (LimeSDR Order 32049)
@Bernard My order number is 32250. C.S. were kind enough to indicate that it would ship this week. That said this was before Limeās offer to modify the boards pre shipping. I would suspect that unless you contact C.S. with your order number to let them know you wish to modify your own Lime then all orders will stay at Lime until after the 21st Feb deadline. That would seem most logical.
Easyfix1 was an easy modification with only the removal of 1 component that would be possible without professional equipment.
if we return our LimeSDR to Crowd Supply, is it not possible to implement Easyfix2?
According to the figures provided by Danny Webster the performance of Easyfix2 is ~ 6-7 dB better then Easyfix1 from 1-1000MHz.
in addition, it is still unclear form me if transmission at the HF band is possible without large attenuation of the output signal. Maybe for HF TX we also need a modification.
@Cornie The options available are no modification or removal of an inductor.
Please understand that there are a great many different ways that matching networks could be optimised, depending on what is important to you. As such itās not simply a case of, for example, compromising on net performance across the entire operating frequency range, so as to optimise for those who are simply interested in general coverage reception. Since this would then rule out use of higher order modulation schemes used in modern wireless systems.
Itās a balancing act and we have to consider all the many different uses.
This will hopefully make it easier to find discussion related to ham radio use with LimeSDR and other Myriad-RF platforms, along with general discussion on the topic, such as antennas and software etc. also.
Again, in the āearly-goā the V1.2 board seemed to have a little better receive to about 40m and then fell off sharply - it played fine in the 20m band and up. When I received my V1.4 board it just seemed a little less sensitive at 40m and just like my V1.2 board had very weak 80/75m reception, and was about the same on 20m and up. But having removed the MN18 coil from both boards and doing consecutive checks across the entire HF band with both receivers with the modified RX1_L Port, both appear to have equivalent performance now - you really canāt tell them apart on the HF band. The VHF frequencies I normally check into (2m band, 162.475 MHz weather, and some police frequencies) both receivers are of equivalent performance there, too, based on my observations.
Sorry Andrew, but based on the measurement data that Lime has made available until now this makes just no sense. If you have more measurements that might lead to other conclusions, then please make these available.
I think we are still waiting for the input loss ā VWSR measurements of the unmodified RXn_L, easyfix1, easyfix2, RXn_W, RXn_H and the TX ports. And TX output power as function of freq.
According to the measurement data provided by Lime the Easyfix2 modification is by far the best compromise for 100 Khz - 1000 Mhz. It has with 6-7 dB better sensitivity compared to Easyfix1 and also better sensitivity then the broadband fix from +300kHz - 1000 MHz
Easyfix1 has the worst sensitivity from 100kHz to 800 MHz. If you think it is a good compromise then what are the advantages that you see, other than that it is simple and most users can make the modification by themselves?
Data above 1000MHz is lacking but here the unmodified RXn_W could be used.
I have worked 25+ years in mobile communication research on high order modulation schemes but I donāt understand why any of the proposed matching circuits would rule out the use of higher order modulation schemes. Can you explain?
Cornelis
I have been following this thread and must say that I am worried where it is heading to.
Your reply to @Cornie deepens my worries.
It looks that the original claim that LimeSDRās range would start from 100 kHz, is downplayed.
The solution of removing one coil is not enough to get the LimeSDR up to standards regarding performance in the lower HF and MF frequencies. Easyfix 2 will give better results and should be considered, because it will bring LimeSDR close or at least closer to its advertised working range.
I agree Easyfix2 is better and I wonder why the mod option is only proposed for RX1_L.
Why not on RX2_L too ?
I may have not understood the whole issue but if the mod is done on the 2 channels RXn_L inputs to get HF, it still gets 2 RXn_W and RXn_H unmodified, isnāt it ?
Iāwill not be able to mod my device by myself.
Iām a radio anthousiats, not an electronic expert, I donāt have skills and knowlage to do it.
Iām donāt know if I will wait or cancel my order, for now Iām little disappointed.
Kinda depends on what you want to do ā¦ one for HF, the other for VHF/SHF ā¦ or mod them all for HF ā¦ seems like a waste to kill off the SHF ability.
With the easyfix1 or 2, on channel 1, only one input is modified, so RX1_W and RX1_H remain the same if I understand correctly.
So the mod will not kill SHF on channel 1 but you wiil need to use RX1_W or RX1_H for this frequency range.
Thatās why one could modify channel 2 the same way to be able to use both channels on HF too with itās RX2_L input.
BUT, if the fix on channel 1 on RX1_L input actually kills SHF on RX1_W and RX1_H I agree that only one channel must be modified to keep channel 2 usable on these higher frequencies.
Thanks andrewback, itās what I was wondering so I think Lime should modify the boards for the _L input for the 2 channels.
Each user will be able to select the best RX port on each channel for its application.
One of the reason I backed the board because of the 2 RXs. I was waiting for HF on the 2.
So I hope Iāll be able to get a modified board that works that way.
Thatās the way I plan on doing mine longer term. Iāve modified the RX1_L Port and (for now) the RX1_W Port for the HF fix. But longer term Iāll reinstall the MN23 coil on the RX1_W Port (yep, I kept all the removed parts) and Iāll have RX1_L for HF /VHF and then will use the RX1_H and RX1_W Ports as-is (unmodified) so I have complete coverage from HF (with RX1_L) to VHF/UHF/SHF (with RX1_H and RX1_W) without too much loss in overall performance to my Lime. Iāll do the same thing for RX2_L (modify it) and then keep the RX2_H and RX2_W Ports unmodified.
It remains to be seen what the TX Ports will look like until I play with those some more first on my V1.2 hardware and then on my V1.4 hardwareā¦Stay tuned on thatā¦
Hi marty, itās the exact setup I would like to get on my board.
But, as I understand the update Lime has published on CrowdSupply, they only give option to get a modified board for HF on channel 1 on RX1_L input. They donāt speak about the channel 2. I emailed them and Iām waiting a reply.
Because I will not be able to mod the board by myself for RX2_L.
If they can do the mod on RX2_L too Iāll keep my order, if they canāt I think I will cancel.
