Good advice.
Being a "show me" type, I took a digital scope home and looked at the
indicated vs. measured rise times for cw keying in my Orion with firmware
version 1.371.
Scope: Tek TDS210 - 60 MHz, 1 GS/s
2.5 ms per division, time measurement cursors adjustable in 0.1 ms steps
Band was 20 meters, run into dummy load Measured last of a short string of
dits at approx 35 wpm, external keying.
Results in ms, average of 5 measurements:
Indicated Measured
3 2.4
4 3.0
5 3.6
6 4.4
7 5.0
8 5.6
9 6.2
10 6.8
The measured rise times were very consistent at a given setting and
increased in 0.6 ms steps as the control was adjusted upwards. As for error,
actual values ran from 80% of indicated to 68% of indicated over the range.
So the full range of control is indeed available for external keying.
Where the manual says "available", it means "recommended", and the warning
message in the CW menu screen when a setting higher than 5 is selected is
only advisory. That's the thing I wanted to be sure about.
Since the cw sidetone is recovered from the transmit signal like the ssb
monitor (right?) it finally occurred to me to try listening to the sidetone
as I varied the rise/fall time setting. Sure enough, the changes were
clearly discernable over the full range of the control. Wish I had tried
that earlier, my question would have been answered the easy way.
So desiring a 5.0 ms rise/fall time, I just set it to 7 and called it a day.
The cw envelope has a nearly ideal raised cosine shape, really pretty to
look at.
Bob NW8L
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Barry Gross
Sent: Wednesday, November 16, 2005 10:40 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] cw settings
On 11/16/05, Bob Cunnings <cunnings@lectrosonics.com> wrote:
>
> Was an indicated setting of 5 "too low"?
>
> If so what is the person using external keying to do?
Ignore the wpm warning. 8 is about right.
Barry N1EU
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