Tuesday, December 1, 2009

Diversity Receiving

No, this has nothing to do with a government program!  By "diversity", I mean capturing your targeted signal in a different phase for better reception and intelligence...i.e., making that station identification when the signal would otherwise fade at the critical moment!

How many times have we sat at the edge of our seat, pencil or pen poised, recorder on and the signal faded right when you tried to make out their call letters?  It can be frustrating...and, in this day and age of slogans rather than call letters, it makes it even harder.  BUT, with the internet at hand, sometimes searching for that slogan and the frequency it was on can help.  Here's something you can do that will also help....

If you have only one receiver at home, you can switch between two antennas, one vertical and one horizontal.  Sometimes, if one is employed and the signal starts to fade, switching to the other can help the signal gain a bit- or, a whole lot!  On my old Hammarlund HQ-100A, I simply have a magnetic CB antenna connected to it and mounted on my desk, vertically.

With its huge accompanying speaker, it has great audio!  Don't discount older tube gear, as they have a nice "warmth" about them, audio-wise and temperature, too!

I have the ability to attach either a horizontal dipole or a 535-foot horizontal loop antenna to this radio, as well.  In fact, if I had them, I could switch as many as six different antennas to any of my radios.  In my "shack", I also have a Kenwood TS-140S (a Ham tranceiver that covers mediumwave AM as well as the shortwave Ham bands) and an older AM/FM/FM stereo receiver, of what manufacture escapes me at the moment, but it is a hot one on both AM and FM.  I also have various portable receivers I can employ that can be attached to an external antenna...but, I'm off on a rabbit trail, so....

The idea is, if you have multiple antennas and one radio, switch between the antennas, or with two or more radios and separate antennas, is to have two or three playing at the same time on the target frequency.  Yes, I know this is hard-core and maybe more trouble than some may want to go to, but if one has a troublesome target they've been trying to identify, sometimes a little more extreme practice can net that station identification!

Let's just say that I have my Hammarlund on the vertical antenna and my Kenwood on the horizontal antenna.  When one experiences fade, chances are the other radio, with the other antenna, will "keep the signal up", enabling me to make a positive identification, or at the very least, enjoy less-faded programming for better enjoyment!

This isn't restricted to big table-model radios; these methods can also be used with portables.

In the receiving world, when you can get away with it, the more antenna, the better, if you are not targeting a specific frequency all the time.  If there are covenants against outside antennas in your neighborhood, a simple 22-gauge stranded wire with a neutral color (brown, blue, black, etc.) can almost be hidden against a background of trees or the home itself, OR, one could loop the wire antenna around the inside of the room or "shack".  There are many, many ideas for antennas and would entail an entirely separate post.  Suffice it to say, just go to your local Radio Shack (also known as "Cell Phone Shack", heh heh!), get a 100-foot roll of stranded 22-gauge wire and throw it up in a safe location, away from power lines(!) and enjoy the signal.  One could get two rolls (or cut one in half) and hang one vertical as high as possible via various methods and the other horizontal across the yard, around the perimeter of the home, etc. and switch between the two.

There are accessories that one could obtain, such as preselectors and tuners, but that is beyond the scope of this post.  Needless to say, on older radios, such as the Hammarlund and others, there is already an antenna tuning control, allowing the listener to tune the radio's circuitry for a better match to the antenna being used.

This may have been overkill or beyond the scope of a casual listener; nonetheless, if you still chase mediumwave DX as I do, looking for "new" ones, sometimes these methods can net satisfying results!

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