JUMA Amateur Radio Forum

Since I cannot leave anything alone for very long, there is now an updated version of the firmware for this transceiver, version 1.07x. This introduces a slightly modified feature, an anomaly fix, (hardly a bug), and some general improvements in the operation. The enhancement allows you to adjust th...

Hi, The output power of the transceiver can be adjusted by means of the carrier level control R28 on the main board. It is normally set to give an output of 10W, but this can easily be reduce to 5W by re-adjusting this potentiometer if you wish. The output power can also be set with the on-board att...

Hi, Robert, Perhaps these notes will help. Let's examine how the bias adjustment for the PA-100D works. If you print out the schematic for this, titled: "JUMA PA100 100W LINEAR AMPLIFIER RF AMPLIFIER BOARD SCHEMATICS", then you can see what's happening. It is important to realise that the ...

There is now a new version of the Juma TRX-2 firmware available, version 1.07w Build 10. This new version fixes some minor bugs, as well as introducing some new features. As before this is 'NOT' an official update, but merely my customisation of this beautiful little gem. If you are updating from on...

First a Happy New Year to everyone. Next, since I can never leave anything alone for long, and as I had some time on my hands over the holiday, I was revising the alarm sub-system code and I noticed that it was possible, under certain circumstances, to disable the High SWR alarm. This was never my i...

During my testing and verification of my firmware modifications, I managed to crash the operating systems of both the TRX2 and the PA100D, and these notes may be of interest. There has been previous mention of a lockup of the PA100D, but I could not find any mention of how it can be provoked. In my ...