AND AUTOSQUELCH IN THE RANGER WITHOUT DRILLING HOLES FOR SWITCHES
by Russell E. Clift, AB7IF
Tired of having to drill holes in your Ranger for a new mod?
Try this. The SWR and Roger Beep functions are open collector outputs pulled to ground by the CPU when the specific function is activated. There are a few more, such as NB and ANL (3 steps), and a voltage function from the Dimmer that can also be used for various mods. Keep in mind that the transistors are not power devices, if you wish to control some circuit needing a larger current sink use a fire train, ie., another device which will handle the load. For example, you can use the SWR or Roger Beep for talkback from the front panel by removing the wire from the connector on the mainboard and simply soldering it to the cathode of D78. Do not cut or remove D78, just connect the wire from the function used to the side opposite the band. Do not connect to the banded side! The green wire from CN607 to the mainboard plug is roger beep, right behind the mike plug 3 inches, a 6 pin connector; black (ground on one end, green (the RB signal control line we want) on the other end. If you use SWR function, go to plug from CN608, just behind antenna output, two coax wires with a common ground. The hot opposite the shield is the one you want to use for a transistor low, activated when SWR is lit on the LCD display. I use both functions because I also have auto squelch, that mod next. Don't forget to open D115 to clean up the audio quality of your talkback. Do not replace the zener D115 with a cap. or resistor or whatever like you have seen out there, just leave it open. A few hundred picofarads here may slightly improve sound but it also affects recieve and PA audio, and I like the recieve sound of my Ranger so I leave the D115 circuit open. If you love SSB like I do but also like the chicken radio talkback with connex, but hate the distorted (lack of carrier for AM detection which is how TB works on Ranger and Galaxy radios) TB on SSB and drilling holes in your new radio, you will love this idea.
Now for autosquelch.
Look at the 3 pin connector from the squelch control, up front just to
the right of center. Wires are violet, grey, and white. Look on bottom,
center pin is grounded. Cut foil to unground. Look to unused pad just
beside 3 pin conn., you will see it goes to 22k to ground. Jumper center
pin to this point. Now at this point you will connect the wire (green)
from the CPU board to roger beep (you removed it from the 6 pin conn.
to RB) to this junction of center pin to 22k to ground. You now have auto
squelch by activating the no longer functioning rober beep. The problem
is: with RB lit you have normal squelch, with RB out you have auto squelch.
So, to invert this like I did (I like things to be on with indicator not
vice versa), connect the green wire to the base of a 2N3904 transistor.
Connect the base to the 10k going to 8 volts. Connect the emmiter to ground,
collector to the center pin on the 3 pin squelch pot. connector. Now you
have autosquelch on when RB is lit, and talkback on (previous mod) when
SWR is lit. COOL!
For better AM recieve
change the detector diodes D34,35 to a better quality SK9975, or use ECG
or NTE 583 (germanium only here, no silicon). While you can reduce the
reciever sensitivity to help overload by changing R78 from 2.2k to 6.8k,
I don't think it is a good idea if you are into long distance communication.
For power limit removal just solder the base of TR32 to ground, looking at the foil side you will see the base lead is closest to the wall, next to a handy close point to ground. Note that some people just clip TR32. I add this info for completeness, this limiter clip or the base resistor to it are always clipped when I see one come in for repair, but keep in mind that doing this limiter removal to the Ranger of any Galaxy radio is hard on the circuitry and can cause problems as well as part failures.
For faster scan and
function speeds replace X601 (a 4 MHZ ceramic resonator) with an 8MHZ
crystal, but remember speeding up the CPU makes it run hotter, and going
to fast will make it prone to locking up.
For you 2970 owners another choice exists. Use the RB or SWR signal to turn the power amplifier on and off. Locate the 2 pin plug going to the linear unit. one wire is the hot 8 volts for transmit. Connect this to the emmiter of a PNP 2N3906, tie the emmiter through 4.7k to the base. Connect the base through 10k to your chosen open collector output either RB or SWR. Connect the collector to the wire going to the linear. Now when you push the front button you will allow or not allow the transmit 8 volts to activate the relay inside the linear unit. More Cool! No holes in the covers and selectable high or low power!
Russell Clift AB7IF Copyright 2001 Russell E. Clift