开云体育

Hi Guys:

I was playing with my Mastr II on 6 meters, getting ready to
devise a way to get PTT from the CAS line (no controller yet).

I tried a 2n3904, but found that it loaded the CAS line. I then
remembered, from repairing TNC's, that they use a 2n7000 FET.
Knowing that the FET has a very lite loading, I tried it. It
works very well, and absolutely no false triggering.

Hoping that this may help someone, here is the scoop:

The 2n7000 has the pin-outs (with the transistor facing you):

1 2 3

Source Gate Drain

-Take the SOURCE to a good ground
-Take the GATE directly to the CAS line
-Take the DRAIN directly to the PTT line

That's it! Works well, and the CAS line doesn't drop at
all in voltage. Just remember to follow standard "anti-
static" precautions.

Now, if I could find a simple solution for the TX audio, hi!


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

Transmit audio can come from the last pin onthe ifas board (I think) labled
rx pa on the schematic you can run this into the mic hi input but do it
through a sutable capacitor to keep the dc off It sounds decent but your
volume switch becomes your repeat audio control.

good luck

tom n8ies

Tedd Doda wrote:

Hello Tedd
I have been using a master II on 2 meters for a long time with a
controller. It should not be difficult to get your recieve audio to the
transmitter, but it will sound tinny if you take audio from the volume
control( before deemphisis ). the easyiest way is to use the speaker
output... 73 Elmer KB3WG

From: "Tedd Doda" <lazer@...>
Reply-To: Repeater-builder@...
To: "Repeater list" <repeater-builder@...>
Subject: [Repeater-builder] Mastr II CAS to PTT (simple)
Date: Mon, 29 Mar 1999 12:57:12 -0500

From: "Tedd Doda" <lazer@...>

Hi Guys:

I was playing with my Mastr II on 6 meters, getting ready to
devise a way to get PTT from the CAS line (no controller yet).

I tried a 2n3904, but found that it loaded the CAS line. I then
remembered, from repairing TNC's, that they use a 2n7000 FET.
Knowing that the FET has a very lite loading, I tried it. It
works very well, and absolutely no false triggering.

Hoping that this may help someone, here is the scoop:

The 2n7000 has the pin-outs (with the transistor facing you):

1 2 3

Source Gate Drain

-Take the SOURCE to a good ground
-Take the GATE directly to the CAS line
-Take the DRAIN directly to the PTT line

That's it! Works well, and the CAS line doesn't drop at
all in voltage. Just remember to follow standard "anti-
static" precautions.

Now, if I could find a simple solution for the TX audio, hi!


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...



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On Mon, 29 Mar 1999 16:55:36 -0500, tom oliver wrote:

Transmit audio can come from the last pin onthe ifas board (I think) labled
rx pa on the schematic you can run this into the mic hi input but do it
through a sutable capacitor to keep the dc off It sounds decent but your
volume switch becomes your repeat audio control.

Thanks Tom. I'll try that next time I open the radio!


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

On Mon, 29 Mar 1999 20:04:22 PST, ELMER HOKEY wrote:

I have been using a master II on 2 meters for a long time with a
controller. It should not be difficult to get your recieve audio to the
transmitter, but it will sound tinny if you take audio from the volume
control( before deemphisis ). the easyiest way is to use the speaker
output...

That's what I'm using now. Took the spk/hi terminal, through
a 2.2uF cap into a 10k pot, feeding the mic/hi terminal. I
find the TX audio "rough"? I thought it would be a smoother
response, but I guess it's easier than taking the descriminator
audio, amplifying it, then using the PL input, hi!


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

Oh Tom I just wanted to say, on the Master II audio, that I don't think
either side of the audio output is grounded....

73 again Elmer KB3WG

From: "Tedd Doda" <lazer@...>
Reply-To: Repeater-builder@...
To: "Repeater-builder@..." <Repeater-builder@...>
Subject: [Repeater-builder] Re: Mastr II CAS to PTT (simple)
Date: Tue, 30 Mar 1999 09:30:59 -0500

From: "Tedd Doda" <lazer@...>

On Mon, 29 Mar 1999 20:04:22 PST, ELMER HOKEY wrote:

I have been using a master II on 2 meters for a long time with a
controller. It should not be difficult to get your recieve audio to

the

transmitter, but it will sound tinny if you take audio from the volume
control( before deemphisis ). the easyiest way is to use the speaker
output...

That's what I'm using now. Took the spk/hi terminal, through
a 2.2uF cap into a 10k pot, feeding the mic/hi terminal. I
find the TX audio "rough"? I thought it would be a smoother
response, but I guess it's easier than taking the descriminator
audio, amplifying it, then using the PL input, hi!


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...



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