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 the bandwidth of the transmit filter. It was previously fixed at 2600Hz, but can now be adjusted between 2500Hz and 3750Hz. For operation on a noisy crowded band, a lower value is probably better; for a local ragchew where speech quality might be desired, then a wider bandwidth can be used.
The anomaly was discovered whilst making this modification. The previous firmware's out-of-band indicator would display, for example on 20m, when the carrier frequency was set to exactly 14.000000MHz rather then 13.999999MHz, also, it would appear when the frequency was set to exactly 14.350000MHz, instead of 14.350001MHz. Since I now had to take into account the variable bandwidth of the transmit filter when using either the USB or LSB mode, this anomaly has now been fixed, and in the CW/CWR/Tune modes the out-of-band indcation will appear when the carier frequency is in fact outside the bad edge rather than at the band edge as before.
I had also had comments that the indicator could be easily ignored, so to remind you it now blinks.
Other minor improvments are the use of a 50-sample running average for the voltmeter display to suppress jitter, as well as the use of real power for the graphic power meter rather than simply RF voltage. Internally there has been a considerable restructuring of the code to simplify the higher levels, as well as the removal of some redundant variables as a result of this restructuring.
As before, this is NOT an official update, but merely my customisation of this little jewel. Since no additional EEPROM is used, nor is the mapping altered, there should not be any checksum error when initially powering up after loading this version, but it would still be worthwhile saving your existing calibration and user setting via the serial test suite. Of course, if you have not updated the firmware before, then the first time you run with the new version there will indeed be a checksum error and you will have to re-calibrate your transceiver as the measurment sub-system is completely different from the original.
The updated user manual reflects these changes, and now has an added section which is the Quick Reference Guide. If you would like to use this new version, please drop me an email, and I'll be happy to send it to you. I can be reached at: adrian04@cytanet.com.cy
73, Adrian, 5B4AIY