[ARC5] NDB IDs

[Kenneth G. Gordon]

On 30 Oct 2012 at 20:09, Dennis Monticelli wrote:

> Yes, MOG is here in California.  After I restored my BC-453-B several
> years ago I started logging beacons with it using the 160M wire. Being
> in an urban location on a city lot I usually had to wait until the
> neighbors were in bed to DX the NDB's.  I have logged almost 100
> different ones from as far away as Puerto Rico and Hawaii as well as a
> Siberian AM broadcast station on this completely stock receiver.  Once
> I took it into the mountains to escape the city noise.  With 12V
> batteries for the filaments and a short stack of 9V (60V worth) it is
> more portable than one thinks.

Thanks, Dennis. I had thought of doing this too, and may do that yet.

And thanks to everyone here who have posted ideas and information on 
input impedance and matching.

Robert Downs has essentially confirmed the same input impedance I had 
thought might be the case from my very peremptory view of the input 
circuitry: 2 megohms.

Brians's ideas will be put into effect as soon as possible. I am going to mount 
one of my very high-quality Stoddart 3 foot-diameter loops on its tripod and 
on the roof and run twin-ax to my shack. All I have to do now is to built the 
UN-BAL to match. I may also build a solid-state preamp for the loop. In fact, I 
think that will be necessary very soon. I'll also have to figure out a way to 
rotate the loop remotely.

As far as the noise here is concerned, it is very frequency-specific, not 
generalized, across-the-band noise. Some of it is very weird sounding and 
VERY loud. Although there is, of course, some across-the-band noise, it is 
not particularly loud, nor does it really interfere with signals.

The addition of a simple diode or dual-diode noise limiter will help that.

We have three computers running in our home constantly, and a wireless 
network, so I, of course, suspect those of being the source of some of the 
noise.

The noise is not coming from the switching supplies, as I have cured an 
especially bad case of that with one of my 7.62 X 54R Mosin-Nagants at 50 
yards some time ago. (Boy! Was THAT fun!)

In the past, I know that the computer monitors (screens), especially, whether 
LCD or tube-based, output noise in the 500 KHz range.

I have also discovered that our computer-controlled clothes-washing 
machine, a Fisher and Paykell, outputs noise when it is running, on almost 
exactly 500 KHz, so noise sources are very variable and unusual.

I also suspect the curly-light bulbs of outputting very frequency-specific 
noise, but have not yet confirmed that.

In any case, my NDB DX so far is YE in Fort Nelson BC, way up north, and 
at least 1100 to 1200 miles from here.

There is also some sort of National Weather Service reporting station in 
Lewiston, Idaho, about 35 miles south of here, that is copyable 24/7 here. Its 
output is AM, BUT, with the BFO on, it sounds like SSB or DSB, and tunes 
exactly like a side-band signal would. It is much more clear with the BFO on 
than with it off.

Also, there are two AM radio stations down quite low, both are in Canada I 
suspect, one at around 535 KHz, the other a bit higher, about 555 KHz. The 
station at 555 Khz was broadcasting a news program from the BBC last 
night.

The reason I am not very definite about frequencies is that I have not yet 
attempted to calibrate the dial, but even after 70+ years, it is still pretty close.

Those of you in the eastern half of the U.S. might listen for the various 
members of the 600 Meter Research Group and affiliates who are actively 
transmitting in the 600 meter band. If you would like me to list specific 
frequencies and modes, let me know and I will attempt to do so. There are 
about 40 stations on the air from that group at this writing, some on CW, 
others on various experimental digital modes.

I will repeat once more for emphasis: in my opinion, the "ARC-5" receivers 
are the very finest single-band receivers ever built.

Ken W7EKB