Juma TRX-2 v5.00a Build 6

Software developed by Adrian

Juma TRX-2 v5.00a Build 6

Postby 5B4AIY » 28 Nov 2018 12:37

Juma TRX-2 firmware version 5.00a Build 6 optimises the operation of the transceiver when equipped with the new active roofing filter. This filter was introduced a few years ago, and improves the performance compared to the original by having narrower bandwidths, steeper skirts, and greater stop band attenuation, all of which significantly enhanced the receiver's performance.

Having now used this filter for some time I found that as the maximum bandwidth of the receiver is essentially determined by this filter, the WIDE bandwidth selection was now redundant. Setting the SCAF filter's bandwidth to anything wider than about 3kHz is pointless, as the roofing filter's maximum bandwidth is 2.5kHz in the SSB mode. This version of the firmware takes this into account, and now the transceiver has only two bandwidth selections, NARROW and WIDE. The NARROW SCAF filter bandwidth can be set from 500Hz to 1,293Hz primarily for CW, and the WIDE bandwidth from 1,293Hz to 3,000Hz, for SSB.

This has had some additional compatibility issues with the Kenwood TS-480 emulation mode. A 'real' TS-480 can have its receiver's upper cut-off frequency set by means of the Set/Read DSP High Frequency SH command. The Kenwood command to set the upper frequency is: SHnn; where nn is replaced with a two-digit number from 00 to 11 and had the following meanings: 00 = 1,400Hz to 08 = 3,000Hz in 200Hz steps, and then 09 = 3,400Hz, 10 = 4,000Hz, and finally 11 = 5,000Hz. If this were implemented precisely then the NARROW filter would never be selected, consequently for the Juma TRX-2 the emulation now sets the receiver's bandwidth from 00 = 500Hz to 11 = 2,700Hz in 200Hz steps. When reading the current bandwidth with the SH; command the response will be: SHnn; where nn has the same meanings as for the Set command.

Similarly, to retain compatibility with F6DEX's CAT program, to change bandwidths the commands are: =WN =WM and =WW but the WM and WW commands will both cause the WIDE bandwidth to be selected.

The Yaesu emulation is also modified to include an additional extended command. Whilst these extended commands are not part of the Yaesu command set, many CAT programs allow the user to save and use custom commands. In which case, to set the receiver to its WIDE bandwidth the binary string is: 01 00 00 00 E8, and to set it to its NARROW bandwidth: 00 00 00 00 E8. Each symbol is an 8-bit byte. For a full description, see Annex-C, Yaesu CAT Command Emulation in the User Manual.

This version of the firmware also fixes a very subtle bug in the status change beep tone logic. Under certain circumstances the beep would be cut short, this has now been fixed.

As there are no EEPROM mapping changes, this version can be safely loaded over the previous version, but, as always, it is a wise precaution to make a note of your existing calibration and configuration settings prior to loading this firmware. There are pages at the back of the User Manual set aside for this data.

NOTE! The only essential precaution to take prior to loading this firmware is to ensure that before loading this new version that you select either the old NARROW or the MID bandwidth and then save this configuration. If the WIDE bandwidth was selected, then when you first load this new firmware and run it, the receiver bandwidth will show up as the transmit bandwidth until you select either the new NARROW or WIDE bandwidth and save this selection. This will not cause any problems other than an erroneous display and bandwidth selection, but is clearly undesirable.

For those wishing to retain three bandwidth selections even with the new filter, obviously you can still use the previous firmware, but bear in mind that the Wide selection does not really affect the receiver's bandwidth, and is essentially redundant.

73, Adrian, 5B4AIY
Juma TRX2 Operation Manual v5.00a Build 6 (Text Only).pdf
Revised and updated User Manual.
(384.52 KiB) Downloaded 88 times
Juma TRX-2 v5.00a Build 6 (C-Source + HEX Load Files).zip
Optimised for use with new roofing filter.
(325.44 KiB) Downloaded 82 times
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