CURRENT FW.VER: 0.53

"RS4K" is a home made controller for the UHF_RX_TX_Modules, wich are part of ERICSSON RS4000 NMT Radio Base Station.

The controller have three modes of operation:

1.DUPLEX MODE + Internal Repeater Logic (UHF Repeater, integrated CTCSS, CW ID, 1750Hz access, simple DTMF administration)

2.DUPLEX MODE + External Logic (Repeater with external controller ; Echolink repeater ; Duplex Link ; etc...)

3.HALF-DUPLEX MODE (UHF Transceiver ; Echolink Link Station ; Half-Duplex Link ; etc...)

---25.nov.2009 - ver. 0.30 - Big part of UI is ready...15.2kB ROM Used, Basic code is now over 1800 lines, much still remains to be done...

---10.dec.2009 - TCXO is ready with TOYOCOM Oscillator +/-2.5ppm (i think i bought enough of these wonderfull oscillators).

---17.dec.2009 - Added an "Optional Galvanic Insulated Interface" for the signals: SQL, PTT, Audio Input, Audio Output.

---15.feb.2010 - ver. 0.44 is tested, the control of the synthesizers is ready, the algorithm for RSSI/NOISE/CTCSS squelch, auto selection and switch-over of RXA/RXB is tested. Some of the results: approximately 2000 checks of incoming signals per second, switch-over between RXA/RXB can occur more than 400 times per second, wich is enough for a good diversity. The hysteresis of squelch and switch-over between RXA and RXB are user configurable. The difference in squelch levels of RXA/RXB can give a priority to one of the receivers. Code is 2200+ lines and used ROM is 17KB. The prototype have new LCD (less than 15mA for LED illumination).

---17.feb.2010 - New version of HW: repeater_ISIS_HW_rev3.5.PDF Changed: some pins, result of impact with another project, now builtin I2C can be used in future, even if I have no any plans for I2C or SPI devices in my project ...hah... but who knows. Another change: PLL_LD signal is integrated by HW, before this was done by SW, now i know: one capacitor can be equal to 30 bytes of firmware.

---22.feb.2010 - ver. 0.46 is ready. Time Out Timer is implemented for all modes of operation. The tail, "courtesy" tone and "TOT expired" tone are OK, so ... IT WORKS :) The first QSO is already a fact. I still have a lot of work on CW ID and other things ...

---23.feb.2010 - Added an optional DTMF decoder based on MT8870 IC. I was thinking about a simple remote administration by 1750Hz tone, but now i hope to have enough program memory for implementation of real DTMF remote administration. There are three options for DTMF radio channel - first and recommended (JP1 ON) - by external second receiver on another band, or an old mobile phone with handsfree connected to DTMF Remote Admin Input (most of them have an option for auto-answer when the handsfree is in use). 2'nd option(JP2 ON) - the external PTT IN is active also in repeater mode and can be used for external VOICE ID logic, telemetry or whatever you like, but the best application is to connect an external second receiver on it (SQL to EXT.PTT input and audio to EXT.AUDIO input). Now you can have a UHF repeater with two input frequencies - 430 MHz and 1296MHz for example (or 50MHz, or 144MHz). I like 1296MHz, usually there are not much stations on 1296MHz, so this can be a stimulus for someone to build 1296 MHz transverter, or just to get the new Alinco DJ-G7 :). DTMF administration will be possible only from this second RX. When a DTMF tone is detected, transmitter will be switched-off, so your codes will not be repeated at the output on UHF band. The 3'th option(JP3 ON) is to use the input frequency for DTMF administration. repeater_ISIS_HW_rev3.6.PDF

---28.feb.2010 - Change: fan multiplexing. repeater_ISIS_HW_rev3.7.PDF

---05.mar.2010 - ver. 048 - New function: Scan for "VFO" and "CHANNEL" modes with three options - "pause on busy", "wait untill busy", "stop on busy". Scan is available only in HALF-DUPLEX mode. For now scanning of 10MHz band with 25KHz step takes less then 4 seconds and it can be even faster. Half of EEPROM memory is used for 124 Channels (+4 special).

---14.mar.2010 - ver. 0.49 - VSWR calculations are done with integer maths, TX power level is now limited according to VSWR. I try to burn out my final and i didn't succeed :), so the limiter work well. Added: STATUS WARNING TONE - if courtesy tone is enabled then "status warning tone" can be enabled also. If there is any warning condition like: VSWR>3.0:1 ; PA TEMP>65 deg.C ; DC < 11.5V , etc... courtesy tone "BEEP" is followed by "BOOP", the tone sounds good - "BEP BOP" and i hope it will not disturb the users, but the repeater keeper will know that there is some WARNING CONDITION. He can send *#4636# (*# INFO #) and STATUS will be returned on CW with message like "VDC 24.2  SWR 3.4  TEMP 45". If "STATUS WARNING TONE" is enabled and supply voltage is under "DC threshold" then courtesy tone is "DOUBLE BEEP" (BEP BEP) , wich mean: the repeater operate on a BACKUP BATERY.

---02.apr.2010 - ver. 0.51 is OK. Almost all settings in MENU >>> SETTINGS was added. Used ROM:27K=42% (3600+ lines).

---06.apr.2010 - ver. 0.52 with CWID and settings for interval (2-60 minutes), tone(500,600,700,800,900 Hz), speed and message(max.127 symbols). I push the CW sending to the limit just for fun :) and I was happy to see error free decoding with "CwGet" at speed 175 WPM! Unbelievable ... with my portable TH-F7E, placed few centimetres away from PC microphone. Used ROM: under 30K. >Screenshot<->Screenshot1<

---30.apr.2010 - ver. 0.53 tested. Minor changes in CWID. 

Lite version of the controller RS4K with less hardware on the board will be used in future project for the conversion of UHF Module into a simple D-Star repeater(only to repeat D-Star signals).

I beleive that the "lite version" will work also with D-star node adapter by Satoshi Yasuda - 7M3TJZ/AD6GZ, i hope to test this some day... 

I have an idea for a few changes in the radio portion of the module, which will turn it into a "linear transponder" or repeater for various signals (QAM, PSK, FSK, ASK, SSB etc.), but probably it will never be realized.