There are a couple things you can check if it appears that the keying
transistor is not being turned on. If you're using a COM port, check
the voltage between the base and emitter of the keying transistor,
which should be in the range of 0.6 to 0.7 volts DC. If its low, you
can reduce the value of the 1K base resistor to turn the transistor on
more fully.
With an LPT port, you can make the same base-emitter voltage check.
Also, check the voltage from LPT pin 1 to ground - this contributes to
the minimum key down voltage measured in the first paragraph. If its
more than 0.5 VDC or so, I would suspect your LPT card is hosed.
Many newer computers come with what are called "bidirectional" LPT
ports. I have no technical details on these ports, so I don't know if
there are any issues which would preclude successful keying. Anybody
have any knowledge on this?
Hope this helps - 73, Dave/K8CC
______________________________ Reply Separator _________________________________
Subject: [na-user] CW control with NA
Author: reisert+list-na-user-outgoing-owner@ve7tcp.ampr.org at SMTP
To: <na-user@contesting.com>
Date: 2/18/97 11:46 PM
Attachment file number 1, file name
Creation date: February 18, 1997 23:46:18
Document Type: ASCI, Document Class: MEMO
Author:
Comment: [na-user] CW control with NA
Level: 1, Number : 1
Here's hoping that some of you have already seen in the past and solved
my current problem...
CW control using NA10.?? on my 486-50, in the key-down mode, gives me
about half-power and a tone that's not clear. Like when I turn the
speed up all the way on my MFJ keyer instead of use the "tune" button.
When I used the same program and interface on an ancient Compaq 386-16
(now deceased), I had no keying problems; clear tone; full power out.
I suspect that I have a nasty-looking ground on the 486, but haven't yet
checked. Anybody experienced something similar, and care to give
details about how to proceed?
Thanks in advance -
Dave (WL7DB in Kenai, Alaska)
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