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LD-5 / LD-11 Page

Tips for Users of these Radios (incl. Firmware Updates)

DISCLAIMER:  We are  not affiliated  with  LNR Precisions in any way. 

This is an unofficial page with the sole intention of providing users of the LD-5 and LD-11 transceivers with information that will help them to better enjoy using these two radios. - DJ0IP


The SKY-SDR, ALT-511, LD-11, and LD-5 are all related products, built in Bulgaria by the same Engineering Team.*  The following information comes from that Engineering Team:

  • LD-5 was their first generation product.  There is no further development planned for this product.
  • LD-11 was their second generation product, using single-threaded firmware.  There is no further development planned for this product.
  • SKY-SDR (and its twin: ALT-511)  are their third generation products,  with nearly the same hardware as the LD-11, but using dual-threaded firmware.

* LZ2TU and LZ1JY (Hardware); RA9YTJ (Software)



The original user manual that came with the LD-11 was very sparce, leaving users with a lot of unanswered questions.  Operationally, the LD-11 is 99% identical to the SKY-SDR.  Nick, LZ1JY has taken the SKY-SDR User Manual (which I wrote) and edited it such that it is usable with the LD-11.


For your convenience, I will present the new manual here as a download.




LD-11 User Manual (Preliminary) Ver. 1.0.1
This is the latest version of the LD-11 User Manual.
PDF-Dokument [763.1 KB]

FIRMWARE  UPDATES  for  LD-5 and LD-11


DISCLAIMER:  The information presented below is posted to assist users of these two great radios in updating the firmware.  It was provided to us by the Bulgarian Engineering Team who built these radios.


To the best of our knowledge, the information is accurate, but

  • Use at your own risk!
  • We are not responsible for any problems or damage that                    may occur by using this information to update these radios.

The procedure for updating the firmware in the LD-5 and LD-11 is exactly the same.  In the document below showing Step-by-Step, how to update the firmware, if it says "LD-11" and you are updating an LD-5, simply substitute "LD-5" where it says LD-11.


Latest Firmware Release:

  • LD-5:    v.1.87.fw
  • LD-11:  v.1.07.fw


  • When you turn the radio on, it briefly shows the logo and the firmware release currently running on the radio.
  • New updates are  "inclusive"  meaning you may update any previous firmware revision directly the the latest revision, without having to update individual releases in between.
  • (i.e., you can go directly from 'v.1.03'  to  'v.1.07'  without      having to first update to 'v.1.04', then 'v.1.05', etc.).




Download the file below and then 


Once you have familiarized yourself with the process, you can then commence with the procedures.


Important:  the update procedures are the same for both radios, but the firmware itself is very different.  Be sure you download the correct firmware for your radio.



Download Step-by-Step Instructions:

Firmware Update Procedures for LD-5 and/or LD-11
These Step-by-Step instructions will guide you through the process of updating the firmware on an LD-5 or LD-11 transceiver.
Firmware Update Procedures.pdf
PDF-Dokument [204.9 KB]


Download Firmware:

LD-5 Firmware Update to v.1.87
This is the latest firmware release for the LNR Precision LD-5.
UPDATE LD-5-v1.87.rar
Komprimierte Archivdatei [170.3 KB]
LD-11 Firmware v.1.07
This is the latest firmware (v1.07) for the LNR Precision LD-11.
Komprimierte Archivdatei [358.8 KB]


This (v.1.07) is the latest and probably last version of firmware for the LD-11.

This version is similar to v.1.06, but has the following improvements:

  • Better Filtering on all bands.
  • Better Filter Shape Factor on Receive.
  • Lower Noise Floor, most aparent above 21 MHz.
  • Improved Unwanted Sideband Rejection.
  • Improved Carrier Suppression on SSB.
  • Increased modulation depth on AM.
  • New deviation algorithms on FM, based on filter width and deviation percentage.
  • Improved balance of audio (both RX and TX) on DIGI modes.


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