by 5B4AIY » 27 Jul 2014 09:26
Hi, Petr,
I'm happy that you like the new firmware for the TRX-1, it's always nice to have some feedback.
Unfortunately there will not be any further updates. It is not possible to include the 60m band in the Rapid Band Switch feature for a number of reasons:
1. There are a number of differing licencing conditions in the various countries, which makes fully automatic band limit monitoring extremely difficult. I thought of this when I modified the Juma TRX-2 firmware and simply had to give up, you would have to have a frequency table for virtually every different administration.
2. Even without the different licencing conditions, there is simply no more memory available. This version of the firmware uses 4081 program words and there are only 4096 words available, so there is only 15 left. It was quite a programming job to get all the features that I have included within the available memory. Part of the difficulty is that the RAM map for the microprocessor is not contiguous - some areas are reserved for the microprocessor's internal use which causes fragmentation of the memory space. This means that sometimes even a minor code change which does not alter the number of program words used does change the RAM allocation map, and the compiler may not be able to find enough contiguous memory. So there is no way of incorporating the 60m frequency allocation in the Calibration & Setup menu - there simply is not enough room.
You can still operate on 60m. You would have to disable the Out-Of-Band detection by setting that option to OFF in the Calibration & Setup menu. When the VFO frequency is higher than 4MHz, then the 20m output filter is automatically selected, so the PA would be using the correct filter. Note however that the second harmonic would be at about 10MHz, and the filter will pass this frequency without significant attenuation, so an external low-pass filter or antenna tuning unit is desirable.
As for making this firmware operate in the RX-1 and TX-1, this would certainly be possible. Essentially the same code is used, except for eliminating the TX code for the RX-1, and, naturally, the RX code for the TX-1. I do not have either of these kits, so I am unable to develop these versions, as I would have to write it 'blind'. Someone else would then have to test it, and the optimisation and bug fixing would become extremely tedious and lengthy.
Nevertheless, these are excellent kits for introducing Amateur Radio, and I wish you every success. If you have need of technical assistance, I will be happy to help.
73, Adrian, 5B4AIY