Proper dah spacing?

Discussion in 'Straight Keys - CW Enthusiasts' started by K2CAJ, Jan 11, 2019 at 5:59 PM.

ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: l-assoc
ad: Left-2
ad: Subscribe
ad: L-MFJ
ad: MessiPaoloni-1
  1. K2CAJ

    K2CAJ XML Subscriber QRZ Page

    I just bought a bug (a Vibroplex Original, it's so awesome) as part of a New Year's resolution to get into CW.

    I followed the instructions to calibrate it, which required playing dits into an Ohmmeter until they showed 50% deflection. Since I didn't have an analog Ohmmeter, I took a spare Arduino and wrote a program to measure duty cycle directly. It's fascinating to see how fine adjustments effect the cycle.

    Having done that, I played a string of DAHs. I am told that a proper DAH is three elements in duration, and if I am not mistaken (???) that implies a 75% duty cycle on a long string of them. Is that right? Because if I play the DAHs at the proper "clock speed" relative to the dits, I measure a duty cycle in the 50s, and it's hard to reach the low 60s. I don't think I can even hit 70%.
  2. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    Don't you find the digital meter display becomes problematic when near high RF fields? I always keep a good analog meter around for this reason.

    Don't overthink it. Listen to your own sending and make it sound like W1AW. Then everything will be adjusted correctly.

    Incidentally, the OT who taught me to use a bug told me, "Tap the dah key, don't press it!" Good advice which helps me to this day.

    It sure is a lot easier to learn to send CW with a straight key than a bug. Lots of people nowadays like to start out on electronic keyers, since that's what most people end up using anyway.
    Last edited: Jan 11, 2019 at 6:15 PM
    W7ASA, WN1MB and M6GYU like this.
  3. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Calibrating a bug for dahs?

    You need to calibrate your finger and ears for proper dah length! :)
    KP4SX, WN1MB, WB5YUZ and 2 others like this.
  4. AG6QR

    AG6QR Subscriber QRZ Page

    That is right. 75%.

    It's good to make it sound like W1AW's code practice sessions, but your own ear can sometimes fool you when listening to yourself as you're sending.
  5. W7CJD

    W7CJD Ham Member QRZ Page

    I suggest find a key you can do it by feeling, not by hearing.

    ..try different types of keys.

    Finally, one will feel right to you.

    I started out by a telegrapher telling me not to use my wrist, rather to balance on my firearm and use my forearm.

    ..that said, I like a tiny portable handmade key best of all.

    I should add, I first got the feel of sending code by mimicking the sound with my voice.
  6. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    This thread is about using a bug. (?).
  7. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Here is one old timer, Denice Stoops, "DA" sending the closing message at the annual "Night of Nights" at KPH with a "speed key".

    K1ZJH, K4RKY, WB5YUZ and 1 other person like this.
  8. K2CAJ

    K2CAJ XML Subscriber QRZ Page

    Well, it sounds fine (I included a beeper with the Arduino circuit) and it feels fine as well.

    I was just surprised to find that when I measured the actual duty cycle of what I was keying, it wasn't anywhere near 75%, and I couldn't even make the gap that short at 15-20WPM. This isn't specific to the bug, either: I tried the same with a straight key, and I can't hit 75% unless I go really slow.

    I suppose it is a matter of developing technique, and drinking less coffee.
  9. N5XH

    N5XH Ham Member QRZ Page

    Have you pondered the possibility of a software problem?
  10. K3XR

    K3XR Ham Member QRZ Page

    Would not get too stressed out over spacing etc. I hear few really bad fist on the air, there are a some. Remember at least 50%, of the hobby, involves listening and that will help as much as anything with sending good CW. Good Luck.
    WN1MB likes this.

Share This Page

ad: KF7PMW-1