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Friday, July 4, 2008

Cleaning up my QRSS Signal

This week I worked to improve the quality of my 30 meter QRSS signal. At first I was pleased to just be in the band and visible on the grabbers. But soon I grew jealous of the very clear and clean dots and dashes of IK0IXI and others. My droopy dashes ("Italian tears") were getting embarrassing. Making matters even worse, when conditions were good, very noticeable key clicks became visible on the grabber screens. These became known among the Knights of QRSS as "shop hooks." I thought they made my signal look like some sort of Arabic lettering. Clearly something had to be done.

Yesterday I put a seven volt zener diode voltage regulator in the oscillator circuit. I also drastically reduced the size of the the capacitor that connects the oscillator to the first RF amplifier. This seems to have done the trick. The clicks are gone and the dashes no longer droop. Power out is now down from 200 milliwatts to 20 milliwatts. That's fine -- this puts me in the power range favored by the Knights.

The narrow-band nature of QRSS work makes imperfections very visible. A chirp or click that would be undetectable on ordinary CW becomes very apparent in QRSS. This morning when I adjusted the air flow from the shack air conditioner, I inadvertently sent the stream of cool air toward the beacon transmitter. With the On5EX beacon on my screen, I could almost immediately see the resulting frequency change!

The on-line grabbers are really fantastic. They give you and almost real-time ability to check band conditions. Almost all day I can see my 20 milliwatt signal arriving at ON5EX. Depending on time of day, you should be able to see my signals here: http://www.on5ex.be/grabber/grabber.html Look for me around 10140060 (+/- air conditioning).

Why isn't there more QRSS activity in the USA? Why are there so few American grabbers?

3 comments:

  1. Hi Bill,
    I knew you would get it figured out! Darn air conditioning is a nusiance :) Here in El Paso at Fort Bliss I have a swamp cooler that wasn't cutting it and my wife and I were miserable. We went out and bought two window air conditoners. Don't you know it, about 2 weeks later the housing people on post came and replaced the swamp cooler with a brand new one! Needless to say we are not hot any more.

    Can you post your schematic? I would like to see it.

    73's
    Alan, W8OAJ

    ReplyDelete
  2. Dang it! Now you're starting to get me into QRSS too:P

    ReplyDelete
  3. Lofers here in the states have been doing this for years. Check out K0LR's site and VE7SL's site

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