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May 6, 2020, Rev 7:
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February 11, 2009, Rev. 6:
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Permission granted to distribute, modify, and/or pilfer - provided appropriate credit is given, thanks!
This presentation was given at:
Am Tech Day @ SLAC, March 2008 & January 2009
Radiofest in Monterey, CA, March 2009
OpenTracker+ (OT1+) modification
OpenTracker+ (OT1+) modification
OT1+ mod motivation
Summary:
My OT1+ serial port was flakey due to excess liquid solder flux (that was conductive) being trapped between the microcontroller socket and the PCB. (This was a kit I soldered myself.) Before discovering this, I made modifications to debug the issue.
Details:
The main motivation for the modifications is that I spent quite a bit of time debugging why the serial interface would work on and off. Sometimes the OT1+ would beacon normally for a few minutes, then no beacon and no OT1+ GPS lock blink. Once in that mode, even the PC could not connect to it. After powering-off the unit for awhile, it would sometimes work again. I suspected the Q2 2N7000 FET was being blown. So I added additional circuitry to protect the FET input from static damage, among other paranoid enhancements in other parts of the design.
After 3 weeks of debug, the problem turned out to be excess liquid solder flux underneath the microcontroller socket near pin 13 (serial data in). The flux caused a low resistance path to adjacent pins or to ground - with a resistance of 1K ohm to ground measured at socket pin 13 (with the microcontroller removed). An oscilliscope on pin 13 showed a voltage swing of less than 2 volts (with GPS unit attached) - no wonder! After removing the flux underneath the socket with a solder flux wash chemical, the resistance changed to 5K ohms to ground - resulting in a full 5 voltage swing at pin 13. Serial port issues resolved!
I'm sure that Argent Data would not recommend these changes.
Someone suggested that using rosin core solder probably would not have these issues.
Peter AF6DS Oct. 2009
OT1+ modification schematic:
OT1+ modification schematic:
To prevent GPS super-cap reverse surge (when source power is removed or shorted), thus protecting the LM7805 voltage regulator and microcontroller. The R11 value was changed from 10K to 3K ohm to provide better serial port levels to the microcontroller. Additional protection circuitry added to the serial port input FET for static and over-voltage. RFI reduction, with 10K pullup resistor, to Transmit Now.
A GlobalSat BR-355 serial GPS receiver (+/- 5V RS-232 voltage swing) is being used with the Argent Data Systems OpenTracker+.
OT1+ modification photo:
OT1+ modification photo:
Surge protection diodes soldered in on top of the LM7805 voltage regulator, low-voltage drop Schottky diode "jumpered" onto +5V and Vext on JP1 (pins 6 and 8), Transmit Now 10K pullup to +5V, 3K @ R11, serial port protection circuit.
Earlier modification photo:
Earlier modification photo:
Tethering a null modem adapter:
Tethering a null modem adapter:
With a cable tie that is secured inside a hole drilled in the OT1+ case - so you can find it when you need it for PC programming.
Yaesu interfacing (to OT1+):
Yaesu interfacing (to OT1+):
HT (e.g. VX-6R) - interface capacitor recommended value change (from 10uF to 0.1uF).
HT (e.g. VX-6R) - interface capacitor recommended value change (from 10uF to 0.1uF).
Mobile (e.g. FT-8900R) cable wiring diagram and notes.
Mobile (e.g. FT-8900R) cable wiring diagram and notes.
Yaesu FT-xx00R to OpenTracker+ (OT1+) cable wiring
OpenTracker+ (OT1+) to Yaesu FT-7900/8800/8900R TNC cable wiring
----------------------------------------------------------------
AF6DS Sept. 19, 2010
Male connectors are used on both ends of the cable. The wiring is for 1200 baud operation, typically used on 2 meters.
OT1+: DB-9 Yaesu: "PS/2-type" 6-pin DIN
pin# / desc pin# / desc
---------------- ------------------------
1 TXA (out) <--> 1 PKD/DATA IN (10K ohm imped, 40 mV p-p max in)
5 RXA (in) <--> 5 RX1200 (10K ohm imped, 300 mV p-p max out)
3 PTT (out) <--> 3 PTT (ground to transmit)
6 GND <--> 2 GND
2 COR/SQL (in) <--> 6 PKS/SQL (open/unmute: +5V, closed/mute: 0V)
Yaesu Data DIN female connector pinout (looking at back of transceiver):
PKD/Data In --- 1 2 --- GND
PTT --- 3 4
RX1200 --- 5 | 6 --- COR/squelch
[Yaesu's RX1200/RX9600 signal names should really be TX1200/TX9600?]
Notes:
OT1+ hardware:
- set jumper on 'HI', not 'HT' (transmit audio level for mobile use)
OT1+ programming (via otwincfg.exe):
- check box: External Squelch (uses the transceiver's squelch line) [the wiring diagram in Yaesu FT-xx00 user manuals does not show the squelch connection being used, but it is used in this case]
- do not check: Invert Carrier Detect (Yaesu has active high squelch)
- do not check: Software DCD (use the squelch line detection instead)
- Tx Audio Level slider bar position: (1/2) midway between min and max [audio level not measured with meter, but checked tracking on aprs.fi]
- increase Tx Delay to 400 mSec, to allow time to switch to the Main band during transmit if the other band is actively receiving
Yaesu FT-8900 specifics:
- the FT-8900R default setting is to receive on the Main band (menu item #27, PCKT B), and transmits only on the Main band
- make sure baud rate is set to 1200bps (menu item #26, PCKT S)
- set Squelch level to be just above the noise such that weak stations can be detected by OT1+ (otherwise OT1+ will not know there will be a collison)
- Volume control knob does not have any effect on the data port signals, e.g. it can be turned all the way down and channel busy/carrier detection will still work
- make sure WIRES mode is not active (toggles by depressing lower-left knob)
- set Audio Mute mode to Tx [menu item #24, MUTE], to mute "Sub" band audio during Main band transmit (optional?)
Motorola MCS 2000 / KPC3+:
Motorola MCS 2000 to Kantronics KPC3+ TNC cable wiring
Motorola MCS 2000 - Kantronics KPC-3+ TNC packet cable
AF6DS 1/25/2009
Female connector Male connector 5 cond wire
DB-25 (MCS 2000) DB-9 (KPC-3+) color
---------------- ------------- -----------
Fixd Rx pin 11 <---------> pin 5 Rx Audio green
== or ==
Spkr + pin 1 <---------> pin 5 Rx Audio [not used]
Spkr - pin 3 <---------> pin 6 Gnd black
Alg Gnd pin 10 <---------> pin 9 Gnd (Mic) brown
Mic pin 23 <---------> pin 1 Tx Audio (Mic) red
(pin 13 ?)
Dtl Gnd pin 4 <---+-----> (cable shield, but braid /
| no KPC-3+ connection) shield
Emergcy pin 9 <---+
PTT pin 21 <---------> pin 3 PTT white
Note: RC network not required for mobile units, only HTs.
Pinouts:
http://johnhigham.com/aprs/instructionsmcs2000kamxl.htm
http://www.moosedata.com/Mods/motorola/gm900.pdf
http://www.kantronics.com/documents/kpc3ppinout.pdf
http://www.kantronics.com/documents/kpc-3plus_manual_RevD.pdf
Yaesu / KPC3+:
Yaesu FT-series to Kantronics KPC3+ TNC cable wiring
Yaesu FT-7900/8800/etc to Kantronics KPC3+ TNC cable
KPC3+ DB-9 male CT-39A 6-pin DIN male
pin# / desc pin# / desc / wire color
---------------- ------------------------
1 TXA (out) <---> 1 Pkt In black
5 RXA (in) <---> 5 Rx 1200 yellow (10K ohm imped)
3 PTT (out) <---> 3 PTT red
6 GND <---> 2 GND brown
Yaesu Data DIN connector looking at back of transceiver (with the CT-39A wire colors shown in parenthesis):
Data In (black) --- 1 2 --- GND (brown)
PTT (red) --- 3 4
Tx 1200 (yellow) -- 5 | 6
Note: The Yaesu FT-7900 and FT-8800 manuals have the CT-39A wire colors are specified incorrectly in the wiring table (but the wiring diagrams are correct), and they do not match actual cable wiring nor the wiring label on the CT-39A package.
ICOM IC-228H / KPC-1:
ICOM IC-228H to Kantronics KPC-1 TNC cable wiring
Kantronics KPC-1 - Icom IC-228H TNC packet cable
AF6DS & KA4PNC 5/24/2009
Male connector Female connector 5 cond wire
5-pin DIN (KPC-1) 8-pin DIN (IC-228H) color
----------------- ------------------- -----------
AFSK pin 1 <--------> pin 1 Tx Mic In black
Rx Audio pin 4 <--------> pin 8 AF Out white (but
not required)
Gnd pin 2 <---+----> pin 6 Gnd (Mic) brown
|
+----> pin 7 Gnd (PTT) green
PTT pin 3 <--------> pin 5 PTT red
Notes:
- Cable shield is connected to 5-pin DIN metal housing.
- Use separate mono audio cable from IC-228H Ext Spkr to KPC-1 Aud In.
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