[HCARC] Fw: Local 10 Meter Propagation Test - Tonight - 6:30 to 6:45 -28.365 Mhz

[galeheise at windstream.net]

To All-

  I've had great responses from people interested in a local HF session.  I 
received a phone call last night from a member who expressed his interest in 
a loosely structured rag chewing session.  Today, Kerry sent me the 
excellent email below.  Unfortunately, it appears we may need to consider 
the General class license operating frequencies to obtain the geographical 
area coverage required for communications with our members.  Possibly we 
should have a survey of members at our next club meeting to determine:

1.  Do members prefer meeting during the day or in the evening?
2.  While we may need to run more tests, it appears to include 
Fredericksburg and Centerpoint we may need to use 14 Mhz or lower 
frequencies.  Is there a band that meets this requirement and most members 
have antennas for the band?

  I appreciate the interest of all those pursuing this issue.

Gale
KM4DR

-----Original Message----- 
From: Kerry Sandstrom
Sent: Thursday, July 26, 2012 12:15 PM
To: galeheise at windstream.net
Subject: Re: [HCARC] Local 10 Meter Propagation Test - Tonight - 6:30 to 
6:45 -28.365 Mhz

Gale,

I checked the ARRL Antenna Book, 18th Edition.  On page 23-4 Figure 3 is
"Typical HF ground-wave range as a function of frequency".  It shows the
following distances :

    Frequency         Distance (miles)

        30                            10

        28                            12

        21                            20

        14                            30

        10                            37

          7                            45

          4                            58

          2                            90

Unfortunately, no indication of the stations capabilities that should expect
these typical distances.  In the text it says that "the surface wave is of
little value in amateur communication, except possibly at 1.8 MHz.
Vertically polarized antennas must be used, which tends to limit amateur
surface-wave communication to where large vertical systems can be erected."
I'm not sure I believe very much of this!  We heard each other very well
during the test at what is supposedely the limit of the 'typical' range
inspite of a vertical antenna on one end and a dipole on your end.  In spite
of the above statements in the Antenna Handbook, the ARRL has encouraged
using ten meters for local nets since at least the 50's.

>From the chart, it looks like 80 and 40 are the best choices if our guys can
get antennas going for those bands.  Unfortunately, after dark, both bands
get fairly crowded.  Ten certainly is the right choice for after dark but we
need to figure out what the station requirements are.  There are a couple
mysteries from the test.  Harvey certainly had a good signal with his low
dipole here, but I don't understand why he couldn't hear me better.  John
was workable here on his high antenna, but I think he should have been
stronger.  The radio line of sight for a 100' antenna is over 30 miles.
Even with the terrain between us, we should have been close to line of
sight.  If Bob was using his vertical, he should have been at least as
strong as Harvey, if not stronger since he is closer to me and our
polarizations match.  Oh well, that is why we need some experiments!

At work I do a lot of propagation modeling.  I have several models that I
can run.  Not one of them does HF surface/ground wave.  The ones that do do
surface wave and near earth propagation are 30 MHz and up.  The ones that
use the ionosphere are all HF only.  There are some MF models that do ground
wave but are all AM broadcast band oriented.  We really are in an area that
most people aren't interested.

Experiments that would be nice:

    80/40 meters in the daytime

    Vertical vs. horizontal on 80 and 40 meters

    Vertical vs. horizontal on 10 meters

    15 meters vs. 10 meters

How did my audio sound during the test?  It was the first time I've had it
on SSB.  I was using an old Shure mobile mike, probably crystal/ceramic.

I only have a cell phone these days, my number is (830) 998-5203.

Kerry