Difference between revisions of "MX800"
| Line 12: | Line 12: | ||
= Interfacing = | = Interfacing = | ||
| − | + | Most interfacing can be done with the DB-15 port on the back, known as CN1 - Line IO. This is mapped to $HEADER on the PCB. | |
| + | |||
| + | {| class="wikitable" | ||
| + | ! DB-15 Pin | ||
| + | ! Junper Pin | ||
| + | ! Function | ||
| + | |- | ||
| + | | style="text-align: center;" | 1 | ||
| + | | | ||
| + | | Alarm output #2 - Open Collector, "short to ground" when active | ||
| + | |- | ||
| + | | 2 | ||
| + | | | ||
| + | | TX VF Loopback active or CTCSS output depending on jumpers | ||
| + | |||
| + | If you want TX VF input to be looped to the RX audio output when active set Jumper 9 to the appropriate position depending if input is high or low. | ||
| + | |||
| + | If this jumper 9 is not placed and jumper 26 is enabled, the filtered CTCSS from the receiver will be output on this pin. This can be used for other functions externally. | ||
| + | |- | ||
| + | | 3 | ||
| + | | | ||
| + | | Receiver audio from speaker amplifier. 4 ohm output. | ||
| + | |- | ||
| + | | 4 | ||
| + | | | ||
| + | | Discrimator output, DC coupled, low impedance. You need a blocking capacitor on this output or you will destroy the amp. | ||
| + | |- | ||
| + | | 5 | ||
| + | | | ||
| + | | Alarm output #3 - Open Collector, "short to ground" when active | ||
| + | |- | ||
| + | | 6 | ||
| + | | | ||
| + | | Alarm output #1 OR M-LEAD - Open Collector, "short to ground" when active | ||
| + | M-LEAD is what most hams want this will give an output when configured in MX tools that COS and PL/DPL are detected. If you want to have an external controller have a PL input you want this as the PL input. | ||
| + | |- | ||
| + | | 7 | ||
| + | | | ||
| + | | RX Talk - this enabled RX VF to the Line ouput and Repeater (TTR). This is needed if you want to have the RX output to line even if PL is not on it. Jumper 12 controls the polarity. | ||
| + | |- | ||
| + | | 8 | ||
| + | | | ||
| + | | Internal Repeater Enable - On/Off of internal repeater function, polarity selectiable by Jumper 14 | ||
| + | |- | ||
| + | | 9 | ||
| + | | | ||
| + | | Transmit Audio Input 600 ohms. Transmitter audio input to op-amps etc.Nominal line input level is -10dBm. Can handle levels between -15dBm and+6dBm. Unbalanced input with common return to analog Earth. | ||
| + | |- | ||
| + | | 10 | ||
| + | | | ||
| + | | Ground | ||
| + | |- | ||
| + | | 11 | ||
| + | | | ||
| + | | TX TALK. Enables or disables TX VF from line as well as TTR VF. Thepolarity is selectable via the internal jumper JMP18. If this function is notrequired then remove jumper JMP18 or place it in position 1&2. | ||
| + | |- | ||
| + | | 12 | ||
| + | | | ||
| + | | PTT - The standard PTT input is active low and may be driven from standard +5V logic outputs or open collector | ||
| + | |- | ||
| + | | 13 | ||
| + | | | ||
| + | | TX DC-FM Input or Wideband Input. Select the internal jumperJMP8 to configure this input as either the DC-FM input or Wide Band input.Remove jumper if not used. | ||
| + | |||
| + | DC-FM input (JMP8 in position 1-2) | ||
| + | Audio or data may be connected to this point. In order to conform to transmitter bandwidth emissions limits, this input is hard limited to the peak deviation and Bessel filtered -3dB @ 3400Hz for minimum group delay distortion. Input impedance is >10k ohms. Input sensitivity is nominally 1Vp-p but depends upon RV2 adjustment. If this input is not used then jumper # JMP8 on the Micro Controller board should be removed to avoid any pickup of stray signals, or alternatively do not connect any wires to this pin. Avoid the use of ribbon cables longer than 30-50cm as this may result in excess coupling or crosstalk. | ||
| + | |||
| + | Wide Band input: (JMP8 in position 2-3) AKA direct modulator input mode | ||
| + | Wide band audio or data may be connected to this point. WARNING: In order to conform to transmitter bandwidth emissions limits, the signal MUST be prefiltered and level controlled, failure to do this WILL result in non-compliance of the TX emission spectrum. This input mode is not normally used except in special cases. | ||
| + | |||
| + | |||
| + | |||
| + | CTCSS Input: (JMP27 in positions 1-2) | ||
| + | TX Subtone audio may be injected into this connection point. Input sensitivity is Fixed at 1Vp-p. AC coupled | ||
| + | |- | ||
| + | | 14 | ||
| + | | | ||
| + | | COR (called RX MUTE). | ||
| + | The RF mute status may be monitored by reading this voltage. +5volt logic signal indicates mute status. This output is not CTCSS dependent. Output impedance approx 100ohms. The polarity is selectable via the internal jumper JMP17. | ||
| + | |- | ||
| + | | 15 | ||
| + | | | ||
| + | | RX Audio 600 Ohms output | ||
| + | Receiver audio output from op-amp. Default nominal line level is set to -10dBm. Unbalanced output with common return to analog Earth. | ||
| + | |} | ||
= DCS Decoder = | = DCS Decoder = | ||
Revision as of 19:15, 6 June 2017
Information on the MX800 Base Station from Spectra Engineering
General Info
Most amps now are wide band, but I've seen a number that do not have the discrete driver transistor. They have a Mitsubishi power module as the first stage and three tuning capacitors. When peeked for maximum power (~60W) they have a 2% bandwidth. As they were tuned for 218 MHz from the factory it's worth retuning for amateur band operation. This will improve the match, which is important when followed with a duplexer.
These 218 MHz amps are not happy doing less than about 25W. Some have displayed spurious emissions when operated out of this 25-50W envelope.
The below was a soft amp. I've found the power out to drop off to less than 50 W (40W normal) at 225 MHz. The MX800 doesn't appear to have a loop power control. Not sure what causes this, but I'll need to test further.
Interfacing
Most interfacing can be done with the DB-15 port on the back, known as CN1 - Line IO. This is mapped to $HEADER on the PCB.
| DB-15 Pin | Junper Pin | Function |
|---|---|---|
| 1 | Alarm output #2 - Open Collector, "short to ground" when active | |
| 2 | TX VF Loopback active or CTCSS output depending on jumpers
If you want TX VF input to be looped to the RX audio output when active set Jumper 9 to the appropriate position depending if input is high or low. If this jumper 9 is not placed and jumper 26 is enabled, the filtered CTCSS from the receiver will be output on this pin. This can be used for other functions externally. | |
| 3 | Receiver audio from speaker amplifier. 4 ohm output. | |
| 4 | Discrimator output, DC coupled, low impedance. You need a blocking capacitor on this output or you will destroy the amp. | |
| 5 | Alarm output #3 - Open Collector, "short to ground" when active | |
| 6 | Alarm output #1 OR M-LEAD - Open Collector, "short to ground" when active
M-LEAD is what most hams want this will give an output when configured in MX tools that COS and PL/DPL are detected. If you want to have an external controller have a PL input you want this as the PL input. | |
| 7 | RX Talk - this enabled RX VF to the Line ouput and Repeater (TTR). This is needed if you want to have the RX output to line even if PL is not on it. Jumper 12 controls the polarity. | |
| 8 | Internal Repeater Enable - On/Off of internal repeater function, polarity selectiable by Jumper 14 | |
| 9 | Transmit Audio Input 600 ohms. Transmitter audio input to op-amps etc.Nominal line input level is -10dBm. Can handle levels between -15dBm and+6dBm. Unbalanced input with common return to analog Earth. | |
| 10 | Ground | |
| 11 | TX TALK. Enables or disables TX VF from line as well as TTR VF. Thepolarity is selectable via the internal jumper JMP18. If this function is notrequired then remove jumper JMP18 or place it in position 1&2. | |
| 12 | PTT - The standard PTT input is active low and may be driven from standard +5V logic outputs or open collector | |
| 13 | TX DC-FM Input or Wideband Input. Select the internal jumperJMP8 to configure this input as either the DC-FM input or Wide Band input.Remove jumper if not used.
DC-FM input (JMP8 in position 1-2) Audio or data may be connected to this point. In order to conform to transmitter bandwidth emissions limits, this input is hard limited to the peak deviation and Bessel filtered -3dB @ 3400Hz for minimum group delay distortion. Input impedance is >10k ohms. Input sensitivity is nominally 1Vp-p but depends upon RV2 adjustment. If this input is not used then jumper # JMP8 on the Micro Controller board should be removed to avoid any pickup of stray signals, or alternatively do not connect any wires to this pin. Avoid the use of ribbon cables longer than 30-50cm as this may result in excess coupling or crosstalk. Wide Band input: (JMP8 in position 2-3) AKA direct modulator input mode Wide band audio or data may be connected to this point. WARNING: In order to conform to transmitter bandwidth emissions limits, the signal MUST be prefiltered and level controlled, failure to do this WILL result in non-compliance of the TX emission spectrum. This input mode is not normally used except in special cases.
CTCSS Input: (JMP27 in positions 1-2) TX Subtone audio may be injected into this connection point. Input sensitivity is Fixed at 1Vp-p. AC coupled | |
| 14 | COR (called RX MUTE).
The RF mute status may be monitored by reading this voltage. +5volt logic signal indicates mute status. This output is not CTCSS dependent. Output impedance approx 100ohms. The polarity is selectable via the internal jumper JMP17. | |
| 15 | RX Audio 600 Ohms output
Receiver audio output from op-amp. Default nominal line level is set to -10dBm. Unbalanced output with common return to analog Earth. |
DCS Decoder
The DCS decoder works, but the CTCSS led doesn't turn on if it's received. The only indication is the M-LEAD which can be configured to be ALARM-1 or M-LEAD. This output is open collector (shorts to ground) when squelch is open and a configured CTCSS or DCS tone is received.
IC18 is the output latch for the LEDs and pin 12 will go high when M-LEAD is active. This is a convenient place to get an active high for DCS/CTCSS active.
MX800-F 220 MHz Technical Brief
Docs
Software
MXtools is the software used to manage the radios.
MXtools V3.1.8028 - Needed for >3.6.0 Firmware.
All these need a password to program the radios, and have different access based on the password used.
'solder' - basic password, lowest access 'solderall' - more advanced password 'solderadv' - more advanced, looks like you can change the model number using this and the channels from narrow/wide 'solderusa' - not sure 'solderalllc' - looks to be the best
Firmware
The firmware sits on a 27C512 64k byte EPROM.
Release notes MX800 Firmware History.txt
Spectra mx800 27c512 firmware image v2.9.6.bin
Spectra mx800 27c512 firmware image v3.0.5.bin
Spectra mx800 27c512 firmware image v3.1.02.bin
Spectra mx800 27c512 firmware image v3.2.5.bin
Spectra_mx800_27c512_firmware_image_v3.5.7.1.bin
Spectra_mx800_27c512_firmware_image_v3.5.14.0.bin
Spectra_mx800_27c512_firmware_image_v3.6.4.2.bin
Spectra_mx800_27c512_firmware_image_v3.6.5.00.bin
Spectra_mx800_27c512_firmware_image_v3.6.8.00.bin
Spectra_mx800_27c512_firmware_image_v3.7.1.2.bin
Spectra_mx800_27c512_firmware_image_v3.7.5.0.bin
Spectra_mx800_27c512_firmware_image_v3.8.0.0.bin
