Elad FDM-DUO Accessories and Information


This modern direct sampling 5 Watt HF transceiver can also be used extensively at LF and VHF using its low power output port for Tx.
Additional hardware makes life easier:

External keypad for direct frequency entry .
Makes life simpler when making wide frequency changes than repeatedly changing the tuning step function.
Full archive with PIC code and PCB layouts here EladKeypad.zip

FDM-DUO_at_VHF.pdf When the DUO is used above 54MHz, external filtering and amplification is needed. This describes the requirements and gives some practical designs.

Coherent Comms
If the DUO is to be used for coherent communications,such as with EbNaut on LF, care needs to be taken with choice of frequency to avoid NCO and DDS rounding errors.
This note describes how to choose frequencies or mitigate the errors that can arise

EladQuickset.pdf When using the transceiver on the different bands, its internal filters and Tx port need to be selected. Doing this via the menu is a bit tedious, so a utility was written to do the selection via CAT commands. Windows. .EXE and an example .INI file are included in EladSet.zip


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