[Premium-Rx] Beacon Hunting

[ToddRoberts2001 at aol.com]

In a message dated 3/30/2005 7:51:26 PM Eastern Standard Time, sid at leben.com 
writes:
Not having experience in using many different receivers, I was wondering
what some of the opinions might be for under 500Kc reception of these AM
DSB beacons.  I listen on CW with narrow BW's.

Most "AM DSB" beacons you are hearing in the U.S.A. are actually transmitting 
A2A which is a continuous carrier on the designated frequency and another 
keyed carrier usually 1020Hz higher - a form of single-sideband AM. This can be 
confirmed by tuning across the beacon in the CW mode with a sharp filter. You 
will hear the continuous carrier on the designated channel, say 216 KHz and as 
you tune higher you will hear the keyed carrier 1020 Hz higher on 217.02KHz. 
If you tune below 216KHz you will not hear the other "sideband" 1020Hz lower. 
This was done to help conserve spectrum space. It will sound like a tone 
modulated carrier when listening with a standard AM detector. I have been listening 
to NDBs for over 25 years and I would have to say the Drake R8A is my favorite 
when listening to these in the AM mode. The R8A has the preamp enabled below 
500 KHz which gives very good sensitivity for beacon hunting and for hearing 
the occasional AWOS voice modulated weather observation beacon. The 2.3KHz and 
1.8KHz bandwidths and the passband tuning are just about ideal for getting 
in-between the crowded signals in the beacon band in the AM mode. An outboard 
audio DSP filter is helpful for eliminating heterodynes. For digging into the 
NDBs in CW mode there are receivers out there with better CW filters than the 
Drake and there are many choices out there for good CW receivers that will tune 
this range.  73 Todd WD4NGG