Re: Users of 2 metre Amateur Band?
"I've got a circuit somewhere for a PIC-based generator that does all the CTCSS tones as well as 1750Hz (and 1800Hz which some Continental repeaters used). The tones (and silence) are selected by a single push-to-make switch that cycles through the options - you replace your old toneburst on/off switch with a push-to-make button or a biased toggle-switch."
Fine, but how do you know what tone you have selected? You need a physical indication...
"The biggest problem with CTCSS-ing old radios is working out where to inject the tone; you can't just put it straight into the mic input like a 1750Hz tone because it's not in the communications-audio spectrum and will be eliminated by the audio low-pass-filter (which should remove anything below 300Hz) - best place for injection is after the speech-processor/clipper.
Good point.
Yet another reason to abandon repeaters...Apathy rules
Another factor that I think is counter productive is the proliferation of commercially sponsored digital modes. There seem to be so many and what do they all do? Apart from sell more rigs?
John
There's a fifth horseman and his name is apathy
|