Megan (jehoshabeath) wrote,
Megan
jehoshabeath

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Zero-beat practice and a noise reduction lesson

Yesterday I got some good practice zero-beating. To zero-beat is to set the radio to transmit on the same frequency as the other station (the one whom you wish to contact). As you turn the dial to listen through the frequencies, CW signals sound sort of like passing traffic. As I come up to them they're very high pitched, and as I pass by them the tones sink deeper until they disappear. In my case, in order to find the frequency where they're transmitting, I just need to find the spot where their tone matches the tone that my radio makes when I send/practice CW. So as I tuned through 40 meters last night, I took time to try and zero-beat each strong signal that I heard. I would stop, tap the key (my new Nye Viking key!) and listen to see if my sidetone (off-the-air) matched the station on the air. If so, I found the frequency where the other station was operating. If not, I had to move up or down in frequency until I found the right spot. This is a very basic radio procedure, but it's something that I still haven't gotten the hang of yet. Thus, I practiced :)

But as I tuned through the band, I noticed that the signals were all drowned out by a high noise level. Hmm, maybe it's just not a good night? Or maybe something in my room is causing excess noise...? I turned off the overhead light - no difference. I looked at the air conditioner, but decided to let it run. (Nope, don't care whether it generates noise or not, I'm leaving it on!) Then, I noticed my laptop...

Note to self: unplug the macbook while scanning the band for QSOs.

Yep, power supplies can sure be noisy - that includes laptop power supplies! With the macbook unplugged, the noise level dropped considerably. I guess that's what happens when I use a little vertical antenna indoors. It's probably picking up a whole bunch of other interior noise, as well. At any rate, after that I was able to catch the end of a conversation about flying between a k1 and a k5 station. W1AW was probably the clearest station that I heard, not counting one down around 7.020-something that was too fast for me to copy. It wasn't a good night for call sign & QSO copy practice, but it still was good to practice zero-beating and investigating noise reduction techniques here in the shack.
Tags: cw, radio equipment
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