I
have done the same thing but have used a 7404 TTL level inverter. But if your COS level goes any higher then about 5.5vdc you will blow
the 7404. I also like using the NTE2358 Digital transistor it has all the bias
resistors build in and is a snap to hook up and put in service.
Gary N0PBM
-----Original Message-----
From: Richard
[mailto:[EMAIL PROTECTED]
Sent: Friday, November 14, 2003
8:52 AM
To:
Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder]
COS Logic Circuit
That circuit actually
should work fine. All it is doing is reversing the logic of your COS
signal. When COS is present (+5V), 0V will be present at the output, +5V will
be at the output when COS is not present.
-----Original Message-----
From: Bruce Morgan
[mailto:[EMAIL PROTECTED]
Sent: Thursday, November 13, 2003
7:59 PM
To:
Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] COS
Logic Circuit
I have a question about logic
circuits. I have a Yaesu FT 1500 that has the data port on the back and I
want to use the 1500 as a temporary receiver in my repeater while the acutal
receiver is out for repairs. Here is my problem, the data output port has a COS
pin out (Carrier=5 volts, none = 0 volts) My contoller port says, Receive COS
(pull this input low when receiving).
So I need to turn my positive logic
signal to a negative logic signal. I found this circuit to do the the
opposite of what I need ( http://www.repeater-builder.com/pix/cosswitch.gif
) Can I and if so how can I modify this to produce the positive logic with no
signal and negative logic when a carrier is present.
Or is my line of thinking completely
out of line?
Thank you.
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