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Latest Posts

Topic Author Posted On
Swapping out xtal - power on or off? KE0KCG 5 days ago
The safest thing is to power the radio down, but chances are your procedure is OK, too. Be careful of possible high voltages inside the radio.

73 Martin AA6E
How exactly does a CW rig work? KE0KCG 5 days, 1 hour ago
Chris -

For CW reception, the receiver mixes the incoming signal (a pure RF frequency, with on-off keying) with another frequency, called the "local oscillator" -- or in older rigs, the "beat frequency oscillator". (A mixer generates a signal having a frequency equal to the difference or sum of two input signal frequencies.) The local oscillator is more-or-less the frequency that your receiver tuning dial reads. (I'm simplifying here.) If you tune 500 Hz off from the incoming signal, you will hear a 500 Hz tone, with the same on-off keying. As you tune slowly back and forth, the tone frequency will vary according to the offset from the incoming signal.

I hope that helps a little.

73 Martin AA6E
The "hissing" noise is probably corona discharge. This will occur with a grounded conductor (especially with a sharp point like a lightning rod) when there is a high electrical field from an overhead cloud. I don't think there's anything you can do to attract or repel lighting by changing the conductors around (eg. grounding them). The main thing is to consider what will happen *when* you get struck or there is a nearby strike -- what path the current is going to take. You need good grounding at the base of the tower and preferably lightning arrestors (like Polyphasers) in your coax lines and rotator lines. (At the tower base is good, and possibly also at the entry to your house.) The hope is to direct the juice directly to ground ASAP, protecting your equipment and your house.

Effective lightning grounding is a tricky business. The typical amateur will try to do something that "looks right", but there is no simple way to know if you've done it properly until the big one comes. (And don't believe everything you read on the Internet!)

73 / GL Martin AA6E
Anybody able to explain this energy wave? KJ6YYC on 23/12/16
Apparently it was an instrumental artifact. Not real data. (Note added to youtube video post.)
feedline in pvc K7WXW on 16/12/16
"Traditional" ladder line (often called open wire line) was made from uninsulated copper wires together with ceramic or other insulators spaced every foot or so. RF burns would be an issue. If you use the fully insulated modern type, the hazard is less, but you still wouldn't want to handle wire carrying much power. You could get zapped from capacity coupling with the wire. Keep in mind that ladder line is often used in high-SWR situations, where the voltage maxima can be quite high (kilovolts) even for moderate power. Treat it with respect!

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