[FoxHunt] IARU Transmitter question

Tue, 13 May 2003 21:31:51 -0600

Sam has brought up a very good point.

We are using the ATX-80 80 meter transmitters.
Our controllers have been modified to assert the OSC enable line before CW
keying starts. This prevents a high current condition that occurs if the PA
is keyed before the OSC is enabled.

At the end of the cycle the reverse occurs, that it keying stops then the
OSC enable line is de asserted.

When we had the original MFC code in our controllers we could observe a
large current spike at the start of the cycle. With the modified code that
does not occur.

Our code is also modified to prevent the "smoke effect" when the led is
blinking in delayed start mode (original MFC controller).

The controllers also have been modified to flash the MO code (with out
keying the TX)during delayed start to see that the transmitters are still in
sync. At the end of the cycle the led goes back to the blinking state. This
lets you know what is going on during delayed start.

Mike K5ATM can give the details on how he modified the code.

Jerry WB8WFK

----- Original Message -----
From: "Sam Smith" <[email protected]>
To: <[email protected]>
Sent: Tuesday, May 13, 2003 5:33 AM
Subject: Re: [FoxHunt] IARU Transmitter question

Byon Garrabrant wrote:
> I'm making a change to PicCon's IARU mode, and have a question I need
> answered ASAP.
>

I can't answer that question, but I do have another suggestion. Last
year for the US Champs I had to kludge a sort of VOX circuit for the 80
meter transmitters. What is needed is a seperate key line and
"transmitter on" line. The "transmitter on" signal would stay active for
the whole minute, while the key line does it's thing. This would assist
those of us using 80 meter crystal oscillators. If we let the oscillator
run all the time, you can DF to the very low level signal from close
range even when it's not transmitting.

What I did last year was use an RC circuit with a few seconds of time
delay so that whenever the key line became active it would keep the
oscillator on.

Sam N4MAP

_______________________________________________
FoxHunt mailing list
[email protected]
http://mailman.qth.net/mailman/listinfo/foxhunt