JUMA Amateur Radio Forum

Hi Erich, Oops! Unfortunately you seem to have discovered one of the design limitations of the Juma TRX-2 power amplifier. This PA, along with many others, is not rated for continuous 100% duty cycle operational modes such as RTTY, PSK-31, Olivia, JT-65 etc, at anywhere near maximum power. Even oper...

Hi, Erich, The Ingenia loader was originally written to execute under Windows XP, but with the advent of the later operating systems, (Win-Vista, Win-7, Win-8, Win-10) it is necessary to ensure that the compatibility options are set appropriately in order for it to execute correctly. As you seem to ...

Hi, Glen, You are correct, the microprocessor comes already loaded with the firmware. As you will have seen from the previous posts on this thread, there appear to be some microprocessors which either do not have the flash-writer or else it is corrupted. I presume that you have tried the various tes...

Post deleted - see later addition with firmware plus bootloader attachment.
Adrian, 5B4AIY

Hi, Erich, I am attaching a ZIP file with the file in it. Test the communication between the transceiver and your RS-232 interface using a terminal program on your computer, make quite sure it is working correctly before updating! Some USB to RS-232 convertors have been found to have problems. The o...

Hi, You will find a plot of the frequency responses of both the old and the new filter in another post of mine on this website, and that shows that the new filter is significantly narrower in both the CW and SSB modes compared with the original. To save you having to search for it, I am attaching th...

Hi, Uwe, The capacitors used in this kit for the low-pass filters are ceramic, and it looks as if this one had a poor dissipation factor, and has absorbed power and burnt out. The best replacement is to use silver mica capacitors for all the capacitors in the filters, but as they are expensive I can...

Hi, Uwe, In version 1.04 of the original firmware, to restore the factory defaults when prompted, briefly press the 'AUTO' button. I am surprised that this is yet another case where the flash writer code is either missing or corrupted and does not execute. Unfortunately, yes, you will have to use a ...

Hi, guys, It is perfectly possible to both control and read the status of the amplifier via its RS-232 serial port. Indeed, some time ago I developed an experimental version to do this from the Juma TRX-2 transceiver, and it was quite satisfactory. It was also possible to control the amplifier and r...

Hi, Paolo, Yes, unfortunately if you have a +5V signal at the junction of R4/R5 when there are no leads connected to the T/R socket, then it means that TR1 has failed and must be replaced. It also shows that the I/O port sensing the KEY signal is working. If there had been no voltage at the junction...