[AMRadio] 505kc (was 450T amp)

Jim Wilhite w5jo at brightok.net
Wed Jun 13 15:58:32 EDT 2007

If I recall correctly the FCC is going to have a bunch of 
spectrum available down in the lower part when the NDB 
stations are mandated to cease operation, what 200-500 KCy. 
All those airport approaches are supposed to switch to GPS 
approaches in the near future, 2012 sticks in my mind as the 
terminal year for NDB operation, but it may be a bit sooner.

In the meantime there is quite an active SWL group who 
monitor the NDB stations.  They have a website for logging 
the reception of the stations and anyone can view the 
reception reports and log theirs.


In years past I maintained a couple of NDBs in the 200 range 
and they used short vertical antennas not over 25 ft. tall 
without radials.  You should have seen the loading coils on 
those.  Some stations had horizontal center fed antennas 
that were about the same height and under right conditions 
they could be heard many miles.  The long range NDB covered 
out to about 300 miles reliably.

I wonder if anyone is pressing for some of that spectrum or 
are they going to save it for something stupid like BPL?


> Our power limit so far on 600 meters is 20w ERP which can 
> take a kilowatt to get as antenna efficiency is ha ha down 
> there. But the little antennas do radiate and the signals 
> go far with easy. Still plenty of room for big tube's. In 
> the winter it only takes 25-35w output power to cover the 
> whole lower 48 states with regular CW. Way further using 
> QRSS of course. Rudy N7LF was seen in the South Pacific & 
> Alaska. Summertime takes more power. EU CW may be possible 
> this coming winter with the guys running larger tube amps 
> as they get experience with the equipment and antennas. A 
> 250TH was on my mind lately...
> Mike
> WE0H
> John Coleman wrote:
>> Cool deal but only 100 watts? And low antennas.  What's 
>> with that?  I guess
>> just to experiment with but if they open it up to all, 
>> then 100 watts is
>> hardly worth the trouble for big glass and iron.
>> John

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