Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by K2WH, Jan 18, 2019.
Can they be modified to use on 630 meters and is there a source for them ?
Good question. And the antenna, and tuning elements?
Here in this part of the US most are at 25 Watts thereabouts, if that's the power level you are looking for. There were a few, longer range NDBs, but it's been a decade or better since the one or two down by the coast of Texas were taken out of service.
Bear in mind, many of these units may have limited "AM" capability, and may have no "mic" input as a tone generator was all that was necessary.
Many private fields in this part of Tx had NDB marking them. They have grown fewer and fewer looking at the NAV charts. A friend of mine had a hobby of tracking them down via RDF techniques.
Many of the NDB transmitters used a mixing technique to obtain the modulated CW. An additional exciter operating 1 KHZ off channel was keyed on/off and mixed to produce the tone that is heard.
As WB5WPA stated most are 25 watt transmitters and are very robust. It would not be too difficult to modify one to use on 630m cw.
And, chasing down NDBs was a fun hobby of mine for many years. Slowly they began to vanish to the point where they're are few in service nowadays.
Indeed they can....and are....being used extensively by the denizens of our new bands.