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Old October 2nd 08, 09:30 PM posted to rec.radio.amateur.moderated
Michael Coslo Michael Coslo is offline
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First recorded activity by RadioBanter: Jun 2006
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Default Radio path prediction

Bill Horne wrote:
This is a sort of follow-up to my post on 80 meter verticals, but in
reading AC7EL's reply, I realized I may be (excuse the expression)
barking up the wrong tree.

I am content with ragchewing to locals on 80, but I also want to have a
reliable path to my brother's QTH, so the question is really "How do I
choose the best band for QSO's from Boston to Washington, D.C."?

Now, obviously, this is a complex topic, but I'm looking for other hams
who've set up similar paths: about 450 miles, IIRC. It's just outside
the range I'd expect from a "NVIS" dipole on 80, but might be short for
40. If you've dealt with similar path lengths, please chime in.



Hi Bill,

Keep in mind that an antenna height that is NVIS on 80 meters, won't
necessarily be so on 40 meters. A backyard dipole should do nicely from
Boston to Washington. I regularly have QSO's from The middle of PA to
all over New England on 40 meters, and get some impressive results on
both ends, So the path is there.

Now on to your band question.

One of the side benefits of doing a State QSO Party is I can see what
bands tend to go where.

And this info is not cast in stone - it is just general.

80 meters is pretty local during the day. Around 200 miles is max. At
night, it extends a lot further. 160 is similar, only worse for
locality. And of course it's quite a job getting a good antenna up for
it. 160 meters would not be a good choice for comms between you and your
brother, and 80 would probably be a little marginal during the daytime

40 meters daytime is usually pretty dependable from local to 500 some
miles. It does some times "go long". When that happens, fairly local
signals, around a hundred miles or so away, will fade away, while
several hundred out will come in great. In the evening, 40 goes
worldwide. When the Broadcast stations finally get out of the Ham
section of 40 meters, it will be a golden age for us. At present, you'll
still be able to reach your desired distance, you'll just have to find a
clear space.

40 is a pretty good choice.


20 meters tends to have an interesting skip path. From Central PA, I get
out Gangbusters to Florida, and the mid and far west. Not so good a
hundred miles away. Some times it stays open late in the evening,
sometimes it closes early

Higher in frequency is more of the same, only exaggerated. 15 Meters
tends to close earlier, etc.


If it were me, I would set up a dipole so that it would fire in the
desired direction, and have the other party do the same. 40 meters would
be the band.

I've purposely not gone too much into propagation models, as I think
they can get a bit unwieldy.

- 73 de Mike N3LI -