R58.en

Nokia Mobira R58 series (band versions RB58, RC58 and RD58)

This page is intended to be a collection of modifications for R58 series radio, to be used for both operating radios and R58's used as repeaters, duplex gateways etc.

---

CTCSS generation/encoding for non-repeater use

Requires R58 firmware 3.Yz or greater.

The RX front-end DAC can be used for generating CTCSS waveform for TX. The modification is easy and requires just two components, a polystyrene 100n capacitor and a 10k resistor to be installed on the A8 audio board beneath the P8 processor board. All settings are adjusted by the handset.

Solder points for the components

Components laid in place

Parameters:

GE:CtCSSt CTCSS frequency in hertz. For frequencies with decimals, use the nearest full hz. eg. 118.8hz would be 119 and 74.4hz would be 74

PH:CtCGEn option rFcdAc selects the RX RFC DAC output to be used as CTCSS waveform generator during TX.

PH:CtGAin sets the amplitude of the generated waveform.

PH:CtHAnG sets the TOC time in millseconds. TOC eliminates the squelch crash at the receiving station, suspending the CTCSS tone transmission prior to the drop of the carrier.

Improved CTCSS tone filtering / Parannettu aliäänen suodatus

Replaces 330kohm resistor and 100nF cap: Korvaa alkuperäisen kytkennän.

  >--- 22kohm ---+--- 22kohm ---+--- 330kohm ----- 15 nF ----> output
                 |              |         
                === 15nF       === 15nF
                 |              |
                 |              |
                GND            GND 

Capasitors can be between 10...20 nF, resistors 18...27 kohm.

Filter simulation

R58 firmware wishlist

The latest firmware is 3.Zi.

Level control does not work in RFC DAC CTCSS generation (works at least in 3.Yz).

Repeater mode needs two additional parameters: one to define minimum length of overs and another to define the number of overs to trigger the shutdown ID. This is needed to make the repeater as quiet as possible in case of kerchunking or somebody just ID:ing or calling another station with no QSO resulting.

There is a special build of the firmware with RSSI reporting to the handset MBUS line, this should be incorporated in the future mainstream builds. There is at least one SIO port available, maybe its application should be considered, too.