Topband: Inquiring minds want to know....

[David Olean]

Hello Topband propagation experts,

I have been messing around with listening to low frequency navigation 
beacons and wondering how reception on 200 kHz relates to 160 meters.  
Not sure there is a correlation.  I have been listening on my 1942 
Bendix aircraft radio, an MN-26C, which covers 150 to 1500 KHz. Well it 
is amazing how many NDBs I can identify. I found about 85 beacons in two 
nights of haphazard listening.  I also located a bunch of them that I 
could hear during the daytime. The daytime stations are close by for the 
most part, although there is a 25 watt beacon in Yarmouth, NS that comes 
in great over a distance  of several hundred miles.

So I was tuning around at 1 PM local time and picked up a fairly weak 
station that signed "OJ" on 239 kHz. I looked it up and it is located in 
northern Alberta and runs 500 watts. I was amazed that I could hear it 
over a 2000 mile path at almost mid day.  I noted that it peaked up best 
on my 330 degree beverage wire. It was also audible on my 290 degree 
beverage wire, but noticeably weaker.  I checked again at 4 PM to see if 
"OJ" was getting any louder. I could not detect it. (?)  I checked again 
as the night progressed and never heard it again.   I began to doubt 
what I had heard. There is another beacon signing "OW" about 3 kHz below 
239 kHz, and located in Ottawa, ON. I had already located it and logged 
it. I wondered if I had miscopied them and got confused, but I cannot 
get OW to peak up at 330 degrees. I do hear OW during the day, but it is 
3 kHz below, and peaks west or NW, but is not audible at 330 degrees 
where OJ was peaking.  I also am pretty sure I was copying OJ as I 
listened to it for about ten minutes and there was no QRM from other 
stations.  If you have ever listened to these beacons, you will note 
that mistakes are very possible as several beacons can be on the same 
frequency at night and tend to make copy problematic as the MCW signals 
combine to produce strange Morse characters. At 1 PM, that was not 
happening. OJ was in the clear and easy copy. Weak, but easy copy.

All this reminds me of the discussions about Marconi's first 
transatlantic transmissions and how many people think it was a fluke or 
maybe "smoke and mirrors".   What the heck happened that I could hear a 
long wave signal over 2000 miles away at mid day?

73

Dave K1WHS

ps. If anyone is interested in my Beacon list, I have a WORD document 
with all these NDBs listed that are audible here in Maine. Typical DX at 
night are 25 watt stations in Iowa and Georgia. I also hear a big NDB 
station in the Caymans.  With so many beacons sharing frequencies, it is 
hard to copy stations beyond about 1000 miles due to QRM.  Sometimes QSB 
can be your friend and you can copy other stations when a closer one 
fades out.